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Aerospace Dimensions

INTRODUCTION TO FLIGHT

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Aerospace Dimensions

INTRODUCTION TO FLIGHT

MODULE

Civil Air PatrolMaxwell Air Force Base, Alabama

1Aerospace Dimensions

INTRODUCTION TO FLIGHT

1Aerospace Dimensions

INTRODUCTION TO FLIGHT

MODULE

WRITTEN BY

DR. BEN MILLSPAUGH

DESIGN

BARB PRIBULICK

CovER PHoTo

WALT BRoWN, ALBUqUERqUE NM

ILLUSTRATIoNS

PEGGY GREENLEE

EDITING

BoB BRooKS

SUSAN MALLETT

DR. JEff MoNTGoMERY

E. J. SMITH

NATIoNAL ACADEMIC STANDARD ALIGNMENT

JUDY SToNE

PUBLISHED BY

NATIoNAL HEADqUARTERS

CIvIL AIR PATRoL

AERoSPACE EDUCATIoN DEPUTY DIRECToRATE

MAXWELL AfB, ALABAMA 36112

THIRD EDITIoN

JUNE 2013

INTRODUCTION

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The Aerospace Dimensions module, Introduction to Flight, is the first of six modules, whichcombined, make up Phases I and II of Civil Air Patrol's Aerospace Education Program for cadets.Each module is meant to stand entirely on its own, so that each can be taught in any order. This en-ables new cadets coming into the program to study the same module, at the same time, with the othercadets. This builds a cohesiveness and cooperation among the cadets and encourages active groupparticipation. This module is also appropriate for middle school students and can be used by teachersto supplement sTEm-related subjects.

Inquiry-based activities were included to enhance the text and provide concept applicability. Theactivities were designed as group activities, but can be done individually, if desired. The activities

for this module are located at the end of each chapter.

CONTENTS

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Introduction .............................................................................................ii

Contents...................................................................................................iii

National Academic Standard Alignment ..............................................iv

Chapter 1. Flight ......................................................................................1

Chapter 2. To Fly By the Lifting Power of Rising Air ........................31

Chapter 3. Balloons - They Create Their Own Thermals ..................38

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National Academic Standard Alignment

Learning Outcomes

- Describe the relationship between Bernoulli’s Principle and Newton’s Laws of motion and how

they were used to develop a machine that could fly.

- Describe the coefficient of lift and the parameters involved.

- Identify the parts of an airplane and an airfoil.

- Describe the four forces affecting an airplane in flight.

- Define the three axes, movement around those axes, and the control surfaces that create the motion.

Important Terms

aero – pertaining to air

aerodynamics – relating to the forces of air in motion

aeronautics – the science of flight within the atmosphere

aerospace – a combination of aeronautics and space

air – a mixture of gases that contains approximately 78% nitrogen, 21% oxygen, and 1% other gases

aircraft – any machine that is capable of flying through the air; included are ultralights, airplanes,

gliders, balloons, helicopters, hangliders, and parasails

airplane – an aircraft that is kept aloft by the aerodynamic forces upon its wings and is thrust for-

ward by a means of propulsion

airfoil – a component, such as a wing, that is specifically designed to produce lift, thrust, or direc-

tional stability

airport – a place on either land or water where aircraft can land and take off for flight

altitude – height above sea level or ground level expressed in units

aviation – the art, science, and technology of flight within the atmosphere

aviator – a person who operates an aircraft in flight

camber – the curved part of an airfoil from its leading to trailing edge

chord – a line drawn through an airfoil from its leading to trailing edge

downwash – the downward movement of air behind a wing in flight

drag – a force which slows the forward movement of an aircraft in flight

dynamic – forces in motion

gravity – the natural force pulling everything to Earth

leading edge – the front part of a wing or airfoil

lift – the upward force that opposes gravity and supports the weight of an aircraft

relative wind – the flow of air which moves opposite the flight path of an airplane

thrust – the force which moves an aircraft forward in flight

upwash – the upward movement of air ahead of the wing in flight

vortex – a spinning column of air that is created behind the wingtip as a result of air moving from an

area of high pressure on the bottom to an area of low pressure on top

wind – air in motion

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GODS, ANGELS, PRISONERS, AND BALLOONSPure mechanical flight involves using some kind of force to lift a machine upward away from

the Earth, thus opposing gravity. A bird is a “living machine” that gets lift by flapping its wings.

Once airborne, a glider is lifted by rising column of air, known as thermals. A balloon is lifted by

a large bubble of warm air. In flight, an airplane is lifted by the dynamic energy forces of the air

upon its wings. But, how did it all begin?

From the beginning of recorded time, there have been myths and legends about flying gods, an-

gels, and other supernatural beings. One of the earliest recorded accounts of manned flight is an

ancient Greek myth that tells of a father and son who were imprisoned on the island of Crete.

They decided that the only way to escape the prison was to fly. secretly, they collected feathers

from sea birds and wax from bees to make wings

for their arms. When the time came, the father,

Daedalus, and his son, Icarus, quietly melted the

wax onto their arms and mounted the bird feathers

to make wings. When the wax was cool, they

started flapping their wings and took off over the

Aegean sea in hopes of reaching freedom.

Daedalus warned his son not to fly too high or

the sun would melt the wax on his arms. Icarus

was having too much fun and disregarded his fa-

ther’s warning, flying closer and closer to the sun.

The heat from the sun eventually melted the wax

The labeled parts of the airplane will be useful in this chapter.

Balloons were the first known powered

aircraft with humans on board.

Airplanes evolved around power

and propellers. (EAA)

Jet engines provide high speed and great reliability. Although

now retired, the Concorde, when in service, could carry passen-

gers across the Atlantic Ocean at twice the speed of sound. (EAA)

Gliders were the first aircraft that

actually had directional control.

Experimental Aircraft Association (EAA)

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on the wings of Icarus, and he plunged to his death in the sea.

Around 1299 A.D., it was written that the great explorer,marco Polo, saw Chinese sailors attached to kites being usedas military observers. This could be considered the first“manned aircraft.”

Historians agree, however, that the first true powered flightwith humans on board was in a hot air balloon and the eventoccurred in France during the Eighteenth Century. Brothers,Joseph and Etienne montgolfier, created a manned hot air bal-loon. On November 21, 1783, pilots Pilatre d’Rozier and Fran-cois d’Arlandes made a historic 25-minute flight over Paris . . .But, let’s start from the very beginning . . .

Then and Now

Early man studied birds, watched them fly,

and even gave names to their parts … but

never quite figured out how they flew.

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NATURE’S FLYING MACHINEIn the book The Fantasy and Mechanics of Flight, the author, Paul Fortin, explains how birds

fly: “There are two phases of bird flight: a ground phase and a lift phase. The ground phase allows

the bird to get started moving forward in order for the wings to provide the necessary lift. To be lifted

by its wings, a bird … must be moving forward fast enough to make air pass over its wings. A bird

can move forward by flapping its wings. Most of the flapping is done by the outer wing The flight

feathers work like the propeller of a plane; i.e., they push downward and backward, thereby driving

the air backward and moving the bird forward. Once the bird’s speed is adequate, lift over the wing

is generated by the same principle as the flow of air over the wing of an airplane.”

A bird’s wing is shaped somewhat like an airplane’s wing. The upper surface is curved more thanthe under surface. Basically, the same principles of lift that apply to an airplane apply to a bird; how-ever, the wings of a bird also act as its propeller. Once again, referring to the Fantasy and Mechanics

of Flight, the author says, “…Slow motion pictures of birds in flight show that the wings move down-

ward rapidly. The wing tips trace a figure eight as

they move though the air. The downward beat of

the wings moves the bird forward as the outer tips

push against the air. Wing feathers are arranged

much like shingles on a roof. They change posi-

tion when the bird is flapping. On the downbeat

of the wing, the feathers are pressed together so

little air can pass through them. On the up stroke

the feathers open.” The down stroke of the feath-ers provide a strong lifting force and the opening,upward action provides a smooth energy-savingreturn motion. You will soon learn that airplaneflight is based upon two laws and bird flight uti-lizes these laws as well.

Like an airplane’s wing, there is a pressure dif-ference between the upper and lower areas of abird’s wing. This creates a form of “Bernoullian

Bernoulli found that the pressure of a fluid, like air, drops

when it is accelerated. An example of this can be shown

when air passes through a tube that has a restriction.

This tube, known as a venturi tube, causes the air to ac-

celerate when it passes through the middle. The pressure

at the restriction drops. Notice the two gauges — the ve-

locity gauge shows an increase and the pressure gauge

shows a decrease. This is the secret of lift for flight that

eluded mankind for centuries.

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lift.” Also, when the bird changes its bodyangle slightly upward to its flight path,Newton’s Third Law of motion takes effectand this is an example of dynamic lift or“Newtonian lift.” Like airplanes, birdsneed to approach and land slowly. A birduses it tail feathers and its wing feathers tosteer, brake, and produce drag, as well aslower speed lift. This greater lift, at a lowerspeed, allows the bird to land without get-ting hurt. The bird is a fascinating, natural flying machine and further study into its mechanism offlight is encouraged.

TWO GREAT SCIENTISTS NEVER FLEW, BUT . . .Although they never attempted to fly, Dutch-born Daniel Bernoulli and Englishman, sir Isaac

Newton, are very important in the history of aerospace. The laws and principles they discovered laidthe groundwork for the science of manned flight both in air (aviation) and in space. These lawshelped develope many aeronautic accomplishments using the science of aerodynamics.

Daniel BernoulliNot as well known as Isaac Newton, but certainly one who holds an honored place in the history

of aerospace science, is Daniel Bernoulli. His discovery of the relationship between pressure and flu-ids in motion became the cornerstone of the theory of airfoil lift. He found that a fluid, like air inmotion, has a constant pressure. However, when that fluid is accelerated, the pressure drops. Usingthis principle, wings are designed to make air flow go faster over the top. This, in turn, causes thepressure to drop and the wing moves upward, against gravity.

Daniel Bernoulli (1700-1782) Courtesy of

the Royal Society, London, England

SIR ISAAC NEWTONIsaac Newton received the highest honor when he was “knighted” for his work in science. That is

why we call him “sir” Isaac Newton today. He not only gavethe world a mathematical explanation of gravity, he figured outhow forces and motion are related to matter. He gave the worldthree laws that are still very much in use to this day:

1. An object at rest will remain at rest unless acted upon byan unbalanced, outside force.

2. A force acting upon a body causes it to accelerate in thedirection of the force. Acceleration is directly proportional to the force and inversely proportional to themass of the body being accelerated.

3. For every action, there is an equal and opposite reaction.

Newton’s Third Law is used to explain how an aircraft islifted against the force of gravity. An example of this can beshown by sticking your hand out the window of a car travelingat highway speeds. Pointing your fingers forward (toward the di-rection the car is going) with your hand tilted slightly upward,your hand should rise. The oncoming wind becomes the actionand the upward movement of your hand is the reaction. An air-plane’s wing acts like your hand. When it is angled slightly up-ward, it, too, receives some of its lift from the oncoming air. Theairflow is the action and the reaction provides lift.

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Sir Isaac Newton (1643-1727)

Courtesy of the Royal Society,

London, England

CAP Cessna 172 Skyhawk ready for lift-off – Photo courtesy of CAP member Alex McMahon

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For years, there has been awidely accepted explanation onhow a wing creates lift and makesthe airplane take flight. many text-books, including ground schoolmanuals for pilot training, ex-plained the theory of lift like this:The upper surface of an airplane’swing (airfoil) is designed with agreater curvature or camber on thetopside. This curved line causesthe oncoming air to flow muchfaster over the upper surface.Using Bernoulli’s Law for proof, itwas stated: as the airflow speedsup, the pressure drops, and it cre-ates a lower pressure as it passesover the top of the wing. With alower pressure above, there has to be a higher pressure on the underside. subsequently, the wing hasnowhere to go but upward toward the lower pressure.

It was also taught that when the molecules of oncoming air split at the front of wing, they traveledover and under this airfoil and met at the back (trailing edge) of the wing at exactly the same time.This is known as the theory of equal transit time. Keep this in mind as it will be discussed later.

Newton’s Third Law was also used in the explanation of how an airplane is lifted against theforce of gravity. A classic example is this: When the airplane’s wing is angled slightly upward, it re-ceives some of its lift from the oncoming air. This example was explained in the text next to New-ton’s picture on page 6.

Both Newton’s and Bernoulli’s scientific laws have been used to explain how a wing lifts. Theseexplanations were basically simple and something any elementary science book could handle. Therewas only one thing wrong. An explanation where Bernoulli’s Law creates the lift, based on the shapeof the airfoil, is not quite right. And— any explanation where Newton’s Laws create most of the lift isalso not quite right. The actual process of creating lift is very complicated. In the world of aerody-namic science, there is an ongoing argument about how lift really occurs!

most every textbook cor-rectly shows all of the partsof a wing. These include theleading edge, upper camber,lower camber, trailing edge,and chord. The actual shapeof a wing (airfoil) has a beau-tiful, graceful form known asa tear-drop. most airfoil de-signs are relatively flatter onthe bottom.

There is an on-going argument concerning the role of Newton’s

Laws of Motion and the pressure differential theory of Daniel

Bernoulli. This illustration, by cartoonist, Robrucha, is presented

here with permission from the artist and KITPLANES Magazine.

A NEW LOOK AT LIFT

THE COMPONENTS OF A STANDARD AIRFOILEven when the air is calm around the airport,

as an airplane moves forward on takeoff, it cre-ates a “wind” that goes in the opposite direction.This air-in-motion is called the relative wind. Atthe beginning of this whole lifting process a lotof power is needed. This is provided by the pro-peller or a jet engine.

As air flows toward the wing, it splits at theleading edge and flows backward to join the un-derside air. most traditional textbooks will saythat the upper and lower air molecules will meet

at the trailing edge atprecisely the same mo-ment. This is wrong.This explanation isbased on the theory ofequal transit time. In re-ality, the air travelingover the upper surfaceof the wing goes muchfaster and much fartherthan the underside air-flow. subsequently, theair flowing over the topgoes beyond and down-ward. This is calleddownwash and createsa huge amount of dy-namic force.

THE WING CREATES A HUGE AMOUNT OF DOWN FORCE ON THE SURROUNDING AIR

When you look at a wing in cross-section, you will see the same tear-drop shape that was men-tioned before. If you study it for a moment and imagine the air flowing around the wing duringflight, you can readily see that the oncoming molecules of air at one point have to split. The upperflow has to bend upward and the lower flow bends to pass under the wing as shown in the diagramabove.

something else happens — the air flow tends to hug the wing. Air is a fluid like water and theflow tends to stick to the wing. As shown, on the following page, take a spoon and hold it under aflow of water from a faucet. Turn the bottom side of the spoon to the water flow and notice how thewater hugs the spoon and then when it “exits” the tip of the spoon, it bends toward the center. This iscalled the Coanda effect.

In the drawing, above, that shows the streamlines of airflow around the wing, look at the mole-cules that are about to split. Now, follow the upper and lower molecules comparing both with your

This illustration shows how the upper airstream goes beyond and

downward compared to the airflow below the wing. Pick the two points

just ahead of the leading edge and follow them backward.

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eyes, and it will soon occur to you that the topflow is really “outrunning” the lower flow. Be-cause of the higher speed of the top flow, and sub-sequent “back and down” action, the air passes thetrailing edge wing and starts downward. This iswhere the Coanda effect comes into play. This“downwash” creates a huge amount of force andthe subsequent reaction is what lifts the aircraftupward. The dynamic downwash force pressesdown so hard on the air, it causes the wing to lift.This enormous energy can be seen in the picture,below, of a Cessna Citation flying over a fogbank. The aircraft has actually pushed hardagainst the surrounding air and the reaction of theair is to lift the airplane. A vortex is visible behindeach wingtip.

The dynamics of total lift are complicated, andit is almost impossible to make it “elementarysimple” for this module. If you want to really getinto the math and theoretical science of how lift occurs check out the following Internet sites, whichare recommended for further aerodynamic study: www.grc.nasa.gov.www/k-12/airplane/downwash.html and http://adamone.rechomepage.com/index4.htm.

An article entitled “A Physical Description of Flight; Revisited”© by David Anderson & scottEberhardt can be “googled” on the internet and will give an excellent, in-depth coverage of flight

science.

This demonstrates the Coanda effect. The blue line

is the direction the water would flow normally.

When the spoon is inserted into the flow, the water

“sticks” to the spoon and bends toward the tip.

This picture dramatically shows airplane down-

wash. The Cessna Citation has just flown above

a fog bank shown in the background. The down-

wash from the wing has pushed a trough into

the cloud formation. The swirling flow from

wingtip vortices is also evident. The picture was

taken by Paul Bowens and the image was pro-

vided courtesy of Cessna Airplane Company.

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This is the Civil Air Patrol Gippsland GA-8. When you

look at this photograph, imagine what the plane is

doing to the surrounding air. As the air passing over

the wing speeds up, it passes behind the wing and cre-

ates a downwash. This puts a force against ALL of the

air surrounding the wing … and the airplane flies.

THE IMPORTANCE OF ANGLE OF ATTACKWhen a pilot, or aviator, pulls

back on the control stick, or yoke,the nose goes upward. In aeronauti-cal terminology, it goes like this:when the pilot pulls back on thestick, the elevator goes upward andthis causes the airplane to rotatearound the lateral axis (the one thatgoes through the airplane wingtip towingtip). The nose pitches upwardand this subsequently causes thewing to also rotate around the lateralaxis.

It is easy to see that this upwardmovement of the leading edge causesthe airflow coming toward the wingto make a much more dramatic “flowchange.” This also increases the dy-namic forces against the underside ofthe wing. As a result of the higher“angle,” or “angle of attack,” agreater downwash is created as theflow exits the back of the wing.Thus, it can be stated that an increasein the angle of attack causes a sub-stantial increase in the amount of liftcreated.

This increase in angle of attackexplains how an airplane can fly up-side down. Although the curvature ofthe wing is greatest (now) on the bot-tom of the wing, an increase in theangle of attack still creates the down-wash and lift is maintained.

In everyday flying, angle of attackis changed many times during the course of a flight. It all beginsat takeoff when a pilot has reached enough speed and then pullsback on the stick (or yoke). This causes the nose to pitch upward.This is shown in the images of the Canadair CRJ – 700 pictured.

The Lockheed martin F-35 Lightning II Joint strike Fighter(JsF) is a transformational weapon system that provides advancedsurvivability and lethality to a fighter-weapons platform.

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This is the pilot’s helmet for a Lockheed Martin F-35 Lightning II. An

Australian Air Force pilot “models” this version. This helmet

is needed because the JSF does not have a traditional heads-up

display. Instead, the computerized symbology is displayed

directly onto the pilot’s visors, providing the pilot with cues

for flying, navigating, and fighting with the aircraft.

The pilot of this Canadair CRJ-700 has increased the angle of

attack prior to takeoff. Angle of attack is also increased just

before landing to slow the aircraft and provide an additional

amount of control at low speed. Image courtesy of Adam Wright,

First Officer, Atlantic Southeast Airlines.

The Lockheed Martin F-35 Lightning II has the ability to take off

and land vertically (STOV/L), or use an increase in the angle of at-

tack in a conventional takeoff (CTOL). Image by Lockheed Martin.

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THE FOUR FORCES ACTING UPON AN AIRPLANE IN FLIGHTThere are four forces acting upon an airplane in flight. They are lift, gravity, thrust, and drag.

Each of these forces has an opposing force. The word “oppose” means to work against. Therefore,

lift opposes gravity and drag opposes thrust. We will expand on these terms for better understanding.

The Two Natural Forces

• Drag - The best way to understand drag is to imagine walking waist deep in a swimming pool.

Now imagine what it’s like to walk faster. It is difficult because of the drag of the water on your

body. A similar resistance occurs when riding a bicycle against a strong head wind. Like water,

air creates drag. Drag is a natural force that is common throughout all of nature, and is espe-

cially evident in flight.

• Gravity - There is a natural force which pulls everything toward the center of the Earth. This is

the force of gravity, and, on Earth, we speak of that force as being one “G.”

The Two Artificial Forces

• Thrust - This is a force that pulls or pushes an airplane forward through the air, and it opposes

drag. In some airplanes, thrust is provided by a propeller; in others, it is provided by a jet en-

gine. This force is artificial because it takes a mechanical device, like an engine and propeller, to

generate it.

• Lift - This, also, is an artificial force because it requires a mechanical device to create the pres-

sure changes discussed in Bernoulli’s Law. Pressure differential creates lift. To put this into

practical terms, when an airplane is ready for takeoff, the pilot adds power and the machine

moves forward. The relative wind starts to flow under and over the wings. The wings ( a me-

chanical device) are being forced to move through air (a fluid).

Look at the diagram of the four forces, then imagine you can see them working on the Vixen airplane. (EAA)

GraviTy (WeiGhT)

Lift = Gravity (Weight)

Thrust = Drag

THE THREE AXESImagine that you are an aeronautical engi-

neer and one of your jobs is to suspend an air-plane from a cable so that it will hangperfectly level in all directions. For the sake ofillustration, let’s say that you are going to dothis experiment in a large building area, like ahangar or a gymnasium. somewhere up high,you would hook the cable to one of the ceilingsupports. The other end would be hooked tothe airplane at precisely the right point whereit would hang level. This cable line would beknown as its vertical axis (the red line).

Now, visualize a line that goes fromwingtip to wingtip and passes through thecenter where the cable suspends the airplane. This side to side line is called the lateral axis (the pur-ple line). Imagine yet another line that passes through the nose and ends at the tail. This line alsopasses through the cable that is suspending the airplane. This nose to tail line is known as the longi-

tudinal axis (the green line).If you hooked your cable at the point where all three of these “axes” come together, that point is

called the center of gravity (denoted by gold arrow). Refer to these axes, as we will continue to dis-cuss them. (see associated Activity One at the end of the chapter.)

Airplanes Can Only Move In Three Directions

In flight, an airplane can only move in threedirections; i.e., nose right/nose left, rollright/roll, and left nose up/nose down. An ex-ample: if you walked out to the end of thewing of this suspended airplane and pushed upor pulled down on its wingtip, it would rotatearound the longitudinal axis. Rotation aroundthis axis is called roll. (see associated diagramon page 14.) If you went back to the tail andmoved it up and down, the airplane would ro-tate around its lateral axis, as shown in the il-lustration to the right. This motion is calledpitch. If you moved the tail from side to side,this would be a rotation around the verticalaxis and is called yaw. (see associated diagramon next page.) Thus, flight is said to be threedimensional. so, how does a pilot get the air-plane to move in these three dimensions? It’sdone by manipulating the moving parts on the plane with the inside control stick (yoke) and the rud-der pedals. By using the dynamic forces of the air as they rush over the control surfaces of the air-plane, the airplane flies. (Refer to labeled airplane parts on page 2, and the descriptions of these parts,as follow on the next page.)

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The Three Axes of an Airplane

Rotation around the lateral axis is called pitch and

the elevator causes this motion. When the

elevator moves up, the nose pitches up. When

the elevator moves down, the nose pitches down.

The Elevator Is Hinged To The Horizontal Stabilizer

The horizontal stabilizer is fixed and doesn’t move. It gives the airplane stability.The elevator is attached to the horizontal sta-bilizer and moves up and down. movement ofthe elevator pitches the nose up or down in arotation around the lateral axis.

The Stabilator

On some aircraft, the horizontal stabilizerand the elevator are one. Engineers call this a“stabilator,” and it works by changing theangle of attack. The stabilator is a very effec-tive method of controlling pitch. When thepilot pulls back on the control yoke (or stick),the stabilator’s leading edge goes down. Thiscreates a “negative” angle of attack and thelow pressure increases on the bottom. Whenthe stabilator is moved, it causes a rotationaround the lateral axis and the nose is pitchedup or down.

Nose Right, Nose Left

When the pilot wants the nose to go left or

right, he/she has to move the rudder pedals

located on the floor of the cockpit. When the

right rudder pedal is pushed forward, this

moves the rudder to the right. The dynamic

force of the air causes the tail of the airplane

to move left and the nose to go to the right.

This movement is around the vertical axis.

The nose right, nose left motion is called yaw.

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Elevator assembly

Stabilator assembly

Vertical Axis

Vertical stabilizer and rudder assembly

Rudder pedals used to created vertical stabilizer

movement in the rudders create yaw rotation.

Wingtip Up, Wingtip Down

If a pilot wants the wings to

move up or down, he/she rotates

the control yoke to the right or left.

Out on the ends of the wings are

located control “surfaces” called

ailerons. When one aileron moves

downward, the other one, on the

opposite wing, moves upward and

vice versa. The airplane then ro-

tates around the longitudinal axis.

This movement around the longitu-

dinal axis is known as roll.

Flaps And What Are They Used For

When a control surface is moved, especially

on a wing, some people will say that the pilot is

“moving the flaps.” In fact, many uninformed

people think that any moveable control surface

on an airplane is called a “flap.” so what are the

real flaps and what do they do?

In the photograph of the Fowler Flaps, to the

right, notice that the trailing edge of the wing is

down. It looks somewhat like the whole back-

side of the wing has dropped. This is somewhat

true — the inboard portion of this airplane's wing

did go down. From an aerodynamic point of view,

study the photograph and visualize the upper camber

of the wing, starting at the leading edge and going all

the way back to the trailing edge. With the flaps down,

the curvature of the upper camber is dramatically in-

creased and so is the wing area. The flaps shown on

this Cessna are known as Fowler Flaps.

When the flaps are down, it causes an increase in

both the upper camber and wing area. This will sub-

stantially increase lift. so there you have the answer.

The flaps actually increase lift so that an airplane can fly slower and still maintain flight. Flaps are

especially useful in landing, where it is desirable to touch the ground at a minimum speed. Flaps are

also used during takeoff and this allows the pilot to decrease takeoff distance. And, finally, flaps in-

crease drag. They act like big "doors" that open into the airstream. During one of your orientation

flights, ask the pilot to demonstrate the use of flaps. Note the airspeed when the flaps come down.

You will also feel a change in the airplane and hear the air rumble around the flaps. The airplane will

rise (increase lift) and the wind will buffet (drag) the flaps. They are very effective in what they do.

(see associated Activity Two at the end of the chapter.)

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The Flaps on a Cessna Skyhawk

Right aileron and flap of a Cessna

(to roll)

(to roll)

THE AERODYNAMICS OF A PROPELLER

When you examine a propeller closely, you soon discover that it is

shaped like a wing on each side of the center, or hub. The reason for this air-

foil shape is obvious, it is a wing. It is a wing designed to "lift" forward cre-

ating a force called thrust.

As the propeller rotates, its leading edge moves through the air and this

motion creates a relative wind. As this rotational relative wind moves

around the curved surface of the propeller blade, a low pressure is created.

This low pressure is a "forward lift," and given enough power, the entire air-

plane will move forward into this area of lower pressure.

The numbers on the propeller

photograph to the right are signifi-

cant points in the aerodynamics of a

propeller. (1) This is the hub. Bolts

go through this hub and fasten the

propeller to the engine. (2) Notice

that this part of the blade is thick

and narrow. Note also that the angle,

called the angle of incidence, is

quite high. If you can imagine this

propeller going round and round at a

certain speed, other than the hub,

this point will be the slowest. Low

pressure, or lift, is created by a high

angle of incidence and greatly

curved camber. (3) The blade has a

longer chord and greater area. The

angle of incidence has slightly de-

creased and, at this point, the speed

is much greater. (4) The angle of in-

cidence is considerably less than

near the hub. The chord is longer

and the speed is higher. (5) Out at

the tip, the speed is tremendous so

there is a smaller chord, smaller

angle of incidence, and a smaller

area. If you think in terms of the

four methods of increasing lift, the

shape of the propeller begins to

make sense.

In the history of one of America’s

most important World War II air-

craft, the P-47 Thunderbolt, it tells how engineers at Republic Aircraft had a difficult time getting the

right propeller for the huge Pratt & Whitney R2800 engine. Eventually they found the right combi-

nation and the “m” version of this aircraft reached almost 500 miles per hour.

15

The propeller blade

Once the engineers figured out the right propeller to harness the

power of its engine, this WWII P-47M Thunderbolt became one of

the fastest fighters in the war.

Starting at the hub, you can see how

the blade changes in angle, chord, and

area on this restored Piper Cub. Just

like a wing, the rotating propeller

harnesses the energy of the air and

converts it to thrust.

UAV – UNMANNED AERIAL VEHICLES They look a bit strange,

and it becomes immedi-

ately apparent that no one

is at the controls when a

UAV passes by on takeoff.

These “UAVs,” stand for

Unmanned Aerial Vehicles.

In a combat zone, if the

enemy spots one, it is

probably already too late

to react. Pilots sitting in a

control center 7,000 miles

away know exactly who

the enemy is and where

they are. The pilot control-

ling the UAV only has to

acquire the target and de-

stroy it. These incredible

machines have just come

into a position of high re-

gard by the U.s. military

and they are feared by our

enemies.

One of the centers for

UAV operation and control

is at Creech Air Force Base

in Indian springs, Nevada.

For several years, the

UAVs were used mostly

for reconnaissance (a pre-

liminary, or exploratory survey of an area to collect information), but as conflicts escalated, they

have taken on a combat role. Of these predators, one version is known as the Reaper mQ-9, and is

one of the most effective combat aircraft ever to go to war. CAP uses the “surrogate predator” for in-

creasingly important missions for non-combat reconnaissance missions. (CAP does not do surveil-

lance. Local authorites do surveillance, as described on the next page.)

In 2006, the UsAF announced that it had a UAV capable of hunting and destroying enemy activ-

ity. It was a modification of an earler UAV series and was designed to carry as many as 14 Hellfire

anti-tank missiles. The mQ-9 UAV can carry bombs and precision-guided missiles to the battle zone.

The aircraft has a ceiling of 50,000 feet and a cruise speed of 260 knots. One of the most notable fea-

tures is its ability to “loiter” in the target area for as much as 14 hours.

In order to give the reader a better understanding of the UAV and its role in the U.s. Air Force

inventory, the following will focus on the role of the mQ-9 as it currently exists.

16

Two Predators are being launched from

Creech Air Force Base near Indian Springs, Nevada

MQ-9, Reaper UAV

17

The mQ-9 is a vari-

ant of the original UAV

used by the Air Force

mQ-9 Predator. It is

manufactured by the

General Atomics Aero-

nautical systems and is

used as a high-altitude,

long range, long en-

durance combat air-

craft. The primary

mission is that of sur-

veillance (a close

watch, or supervision,

of an area after reconnaissance, or “recognition” of something in the area).

The mQ-9 has a 950 horsepower (hp) turbopropeller engine. There are several terms used in this

new aerospace technology and they include: UAV - Unmanned Aerial Vehicle; UAs - Unmanned

Aerial system; and RPV - Remotely Piloted Vehicle. All of these terms are used in basically the

same context.

Although the mQ-9 can fly on pre-programmed flight plans by itself, it is constantly controlled by

flight crews located at Air Force installations known as GCs, or Ground Control stations. By the end

of 2009, the U.s. Air Force had a total of 195 Predators and 28 Reapers in its inventory.

NAsA has also been using a UAV in its continuing research efforts. One example, the Ikhana, has

been extensively used in combating wild fires in California. This demonstrated that UAV’s are ex-

tremely valuable in the private sector, as well as in military service. (see associated Activity Three at

the end of the chapter.)

THE BIG BIRD –GLOBAL HAWK

Another UAV that has beenused in the combat arena isthe Global Hawk. The imageshown is a Grumman RQ-4 inroute to record intelligence,surveillance, and reconnais-sance data. Because of itslarge coverage area, the re-motely-piloted aircraft has be-come a useful tool forrecording data and sending itto warfighters on the ground.

The Global Hawk is builtby Northrop Grumman and isprimarily used by the UsAF

With smoke from Lake Arrowhead, CA, fires in the background,

the NASA Ikhana UAV heads out on a wildfire imaging mission.

A ground control station crew performs post takeoff checks after

launching an earlier Predator MQ-1 from Ballad Air Base in Iraq.

USAF image by Master Sergeant Steve Horton

18

as a surveillance aircraft. It is equipped with synthetic Aperture Radar that penetrates heavy weather,including sand storms. It has the ability to survey over 40,000 square miles in a day. specificationsinclude:

• Empty weight is 9,200 lbs

• Payload is 1,900 lbs for the RQ-4 and 3,000 lbs for the RQ-4B

• maximum gross take-off weight is 25,600 lbs (the RQ-4B version weighs 32,250 lbs)

• Engine is a Rolls Royce North American AE3007H turbofan

• Loiter on station is 24 hours

• Loiter velocity is 343 knots TAs

• maximum altitude is 65,000 ft

• Wingspan is 116.2 ft (RQ-4B - 130.9 ft)

• Length is 44.4 ft (RQ-4B - 47.6 ft)

• Height is 15.2 ft

• Length is 44.4 ft

• Wing area is 540 ft²

• Wing aspect ratio is 25:1

(see associated Activities Four, Five, and six at the end of the chapter.)

The deadly-looking Global Hawk is on an Air Force

mission somewhere in the world. USAF photo.

19

11Activity One - The Soda Straw Three Axis DemonstratorPurpose: This activity will demonstrate how the three axes of flight in an airplane works.

Materials: 3 soda straws and a hand-held, single-hole, paper punch

Procedures:

1. Punch 2 holes in the center of one of the straws. These holes should be near the center and per-pendicular to each other.

2. Pull 1 soda straw through 1 of the holes. You now have two axes. 3. Insert the third soda straw into the remaining hole. What you now have is a three axis demon-

strator. Refer to top illustration on page 2, which displays labeled airplane parts. Now, imaginethat your three axis demonstrator is an “airplane.” If you hold one straw on each end, that’syour “wings.” If you rotate the straw, you are pitching the demonstrator around the lateral axis.If you grab the vertical straw and rotate it, you are “yawing” the demonstrator to the left andright. And finally, if you grab the “nose” and “tail” ends of the straw, and rotate it, you are“rolling” the demonstrator, such as tilting from side to side.

(Note: You can also attach your axis demonstrator to a balsa, paper, or other model airplane forthe procedures above.)

Summary: The three axes of flight in an airplane pass through the airplane’s center of gravity, whichis that point located at the center of the airplane’s total weight. The longitudinal axis (green straw indiagram) extends lengthwise through the fuselage from the nose to the tail. movement of the air-plane around the longitudinal axis is known as roll and is controlled by movement of the ailerons.The lateral axis (blue straw in diagram) extends crosswise from wingtip to wing tip. movement ofthe airplane around the lateral axis is known as pitch and is controlled by movement of the elevators.The vertical axis (red straw in diagram) passes vertically through the center of gravity. movement ofthe airplane around the vertical axis is yaw and is controlled by movement of the rudder.

The three-axis soda straw demonstrator was developed by Dee Ann Mooney,

Civil Air Patrol member and math teacher at Big Sky High School, Missoula, Montana.

vertical axis

longitudinal

axis

lateral

axis

Purpose: This activity teaches,by modeling, about a delta wingconfiguration airplane and thecontrol surfaces of this paperairplane by using experimenta-tion and the inquiry method.

Materials: a sheet of standardprinter paper and scissors

Procedures: Follow the in-structions as outlined in the diagrams

Summary: The control surfaces of this paper airplane are the elevons (a combination of a conven-tional elevator and ailerons) and the rudder (which causes the airplane to yaw left or right). When themaneuvers are correctly performed, the conclusion can be reached that the paper airplane is similarto a real airplane.

20

Activity Two - Folding, Flying, and Controlling the Flight of a Paper Airplane

Small cuts on solid lines for elevons

(combination of elevators and ailerons)

Small cut for rudderFold on dashed lines to

make control surfaces

1. First, a sheet of standard

printer paper is folded in half,

"hot dog style." Then it is folded

back, as shown. The two upper

edges fold to the center.

2. A portion of the outer edge is

folded to the center. Make sure

the both sides are equally folded.

3. The wings are folded outward

and the two halves are held to-

gether either by a staple or tape.

4. Make small cuts, as shown, to manipulate the

“control surfaces” which will control direction of flight.

5. Fly your airplane to create the three directions of flight: nose up/nose down, nose right/nose

left, roll right/roll left. How do you accomplish this? Refer to the directions in chapter 1, found

on pages 12-14, to adjust movable control surfaces. Also, refer to further directions on pages

21-22. The questions at the end are suggestions on how to expand this activity.

21

Components of a Paper AirplaneThe paper airplane has components just like a real one. The wings of our activity model have a

“delta” shape; i.e., they come to a point at the nose like an arrowhead. At the back of the delta wing

you were asked to make two cuts and to become control surfaces known as “elevons.” This is a

combination of conventional elevators and ailerons. since the elevator makes the airplane's nose go

up and down, both of the paper airplane's elevons in the up position will make the nose pitch up

when you throw it. If one elevon is down and the other is up, the actions of the ailerons are enacted

and the aircraft will spiral through the air when thrown. This motion is called roll.

The Three Axes of a Paper AirplaneNow, let's mark the paper airplane to match a real one. A line drawn from nose to tail going

through the center is called the longitudinal axis. A line drawn from side to side passing through the

center is called the lateral axis. A line drawn down through the center from top to bottom is called

the vertical axis. All of these lines (axes) will pass through the exact center of the paper airplane;

this point is called the center of gravity. To find the center of gravity, get a piece of thread, some

household tape, and see if you can make it hang perfectly level in all directions.

The paper airplane has a delta wing configuration.

The famous Concorde had the same design.

Don't throw a sharp-nosed

paper airplane at anyone

(might want to fold and tap

the point inward for safety).

22

Making It Roll

The first paper airplane flight maneuver is an easy one.simply put one elevon up and the other elevon down.Throw the paper airplane and it should spiral through theair rolling several times.

Making It Pitch

You can make the nose of the paper airplane pitch upor down by adjusting the elevons. If you put both elevonsup to a 40 degree angle, it should fly forward, pitchingupward, and then stall. Once it stalls, the nose will pitchdownward and it will head for the floor. You can experi-ment with various elevon settings so that the aircraft willstall several times before hitting the floor. These multiplestalls are called secondary stalls.

One of the more difficult maneuvers is to make thepaper airplane land gently. Try this experiment with various elevon settings. Put the elevons upmaybe 10 degrees and give it a toss. It may glide forward or roll slightly. If this happens, adjust eachelevon until it flies straight. Then fold the elevons a few more degrees and, eventually, your paperairplane should glide in for a very smooth landing.

make a “runway” on the floor using masking tape or a piece of cardboard. This runway shouldbe about 4 feet long and 1 foot wide. stand about 20 feet from one end of the runway and try to“land” your paper airplane on the surface. If you find this too easy, back away another 20 feet andgive it a try.

Be A Paper Airplane Test Engineer With These Suggested Activities1 What is the length of your paper airplane in inches and centimeters?

2. What is its exact wingspan?

3. Can you determine the chord of a delta wing?

4. How much does your plane weigh in milligrams, grams, kilograms, and ounces?

5. Where is the exact center of gravity?

6. measure the greatest distance it will fly in meters and feet.

7. At what carefully measured point in its flight does it stall?

8. Can you make it fly in a long, wide turn?

9. In competition with another person, “Calling Your shot” is a fun activity.

a. Call for a spot landing.

b. Call a pitch and make the aircraft descend into a trash can.

c. Call a roll and make it fly through a hoop.

d. Call a stall to a spin.

10. Develop a computer program for the flight test of a paper airplane.

23

Activity Three - MQ-1 Predator

Purpose: Build a Predator and observe how it flies.

Materials: foam board or meat trays, hot glue gun, spray glue, snap knife, pennies, and copy ofPredator cut outs (template) on the next page

Procedures:

1. Attach the page of cut outs with spray glue to the foam board or meat tray.

2. Cut out the designs.

3. Use the red-dashed lines that indicate where to put glue or hot glue used to bond together the

pieces of the aircraft.

4. Fly your airplane.

5. Experiment with different nose weights until the plane flies, as desired.

Notes: Foam works very well for making flying models. It is strong, very light weight, and inexpen-sive. styrofoam meat trays from the grocer work well, and are free! The following recommendationswork well for a group activity:

• It is recommended that you use a low-tack spray glue, such as 3m spray mount™ to bond thetemplate to the foam board or styrofoam meat tray.

• Use a hobby knife or a “snap knife” to cut out your foam pieces. (Adult supervision needed.)

• Hot glue guns have an adhesive that works very well on foam board for attachment of wings andstabiliser elevators.

• There is also foam “glue” that is available in craft stores like Hobby Lobby™ and some hobbyshops. This works well, but takes longer to dry. You might ask for “Helmar” foam glue if youneed a brand name. (It also works well on cardstock, for other activites.)

• It is recommended that you build one complete side of the model first. Get it perfect and then at-tach the opposite pieces for alignment.

• Foam flyers also need nose weight to better stabilize or balance the plane for better control.Using hot glue, you can experiment with pennies, dimes, or gem clips until the desired stabiliza-tion point is achieved.

Summary: The General Atomics Aeronautical systems mQ-1 Predator is an unmanned aerial ve-hicle (UAV) which the United states Air Force (UsAF) describes as a mALE (medium-altitude,long-endurance) UAV system. more information was discussed on page 17 to describe its purposein use. Learning to fly this model, while experimenting with nose weights and amount and directionof thrust use to fly it, can aid in better understanding of the complexities of maintaining proper bal-ance to achieve and maintain flight.

24

MQ-1 Predator Template

(Manufactored by General Atomics Aeronautical Systems)

MQ-1 Predator

25

Activity Four - Northrop Grumman RQ-4 Global Hawk

Purpose: Build a Global Hawk and observe how it flies.

Materials: foam board or meat trays, hot glue gun, spray glue, snap knife, pennies, and copy of theGlobal Hawk cut outs on the next page

Procedures:

1. Use spray glue to attach the cut outs (templates) on your foam board or meat tray.

2. Cut out the designs.

3. Use the red-dashed lines that indicate where to put glue or hot glue used to bond together the

pieces of the aircraft.

4. Fly your airplane.

5. Experiment with different nose weights until the plane flies, as desired.

Notes: Foam works very well for making flying models. It is strong, very light weight, and inexpen-sive. styrofoam meat trays from the grocer work well, and are free! The following recommendationswork well for a group activity:

• It is recommended that you use a low-tack spray glue, such as 3m spray mount™ to bond thetemplate to the foam board or styrofoam meat tray.

• Use a hobby knife or a “snap knife” to cut out your foam pieces. (Adult supervision needed.)

• Hot glue guns have an adhesive that works very well on foam board for attachment of wings andstabiliser elevators.

• There is also foam “glue” that is available in craft stores like Hobby Lobby™ and some hobbyshops. This works well, but takes longer to dry. You might ask for “Helmar” foam glue if youneed a brand name. (It also works well on cardstock, for other activites.)

• It is recommended that you build one complete side of the model first. Get it perfect and then at-tach the opposite pieces for alignment.

• Foam flyers also need nose weight to better stabilize or balance the plane for better control.Using hot glue, you can experiment with pennies, dimes, or gem clips until the desired stabiliza-tion point is achieved.

Summary: The Northrop Grumman RQ-4 Global Hawk, asdiscussed on page 17, is a remotely-piloted aircraft used bythe United states Air Force and Navy as a surveillance air-craft. Learning to fly this model, while experimenting withnose weights and amount and direction of thrust use to fly it,can aid in better understanding of the complexities of main-taining proper balance to achieve and maintain flight.

26

NorthropGrumman RQ-4GlobalHawk Template

RQ-4 Global H

awk

27

Activity Five - The Race to the Top! Purpose: This activity is a contest between the flying models built in activities 3 and 4, the Global Hawkand the Predator, to learn about different aircraft ad how their designs and performance are different.

Materials: pre-prepared airplane models for contest

Procedure:

1. This is a contest using the pre-built Global Hawk and Predator foam models.2. Divide the participants into two groups; one group using the Global Hawk model, and the other

group using the Predator model.3. Test Flight Phase- Each participant gets 5 minutes to “test and tweak” their foam models. This

can be done in any open area, such as a gym or outdoors. Weights can be added and/or adjusted,as needed, to prepare for the contest.

4. Contest Phase- Each participant flies his/her foam model to determine and record the followingon the Contest Form on the bottom of this page:a. Longest distanceb. spot landing accuracyc. How much of a circle made when flying with angular degreesd. How to fix the elevators so it causes the nose to go up and stall the aircraft

5. To determine team winner of contest, compare 2 categories: distance (part a above) and sum totalof parts b, c, and d above. If one team is highest in both categories, there is a clear team winner.If each team wins in one category, winners could be declared for each category. Or, there couldbe a “fly off” between the top distance scorer on each team with the longest distance winner“breaking the tie.”

Summary: In this activity the contest provided ways to test the construction of the models from Ac-tivities 3 and 4. This activity will also promote the inquiry method to solve problems based on desiredresults and the variables that can cause such results.

Contest Form for: ___________________________________ Company President:__________________________

Company Members:________________________________________________________________________________

Participant’s Type of Distance Accuracy Degrees of a How was Stall Total Points

Name Aircraft Circle Flown Accomplished

Record Averages

in this Row

Find the average for each category of competition except Stall column and record on the last row.

28

Activity Six - Build the SR-71 Blackbird Purpose: This activity teaches how to build a model of the sR-71 Blackbird, fly it as a foam glider,and demonstrate an understanding of the words fuselage (the body of the plane) and nacelle (the en-closed portion covering the engine outside the fuselage).

Materials: piece of 1¾” outside diameter foam pipe tubing cut to a length of 14 inches (found atlocal hardware or super center stores), two pieces of foam tubing cut to 4 inches, a foam meat tray, a#64 rubber band, a nylon cable tie, a metal washer, tape, spray-on glue, hot glue gun, Exacto knife orother cutting device (adult supervision needed), and copy of sR-71 Blackbird template found onpage 29

Procedure:

1. Cut out paper cones on template sheet and hold for later use.2. Attach the remaining template to the meat tray with spray-on glue.3. Cut out the wings and fins templates.4. Hot glue the wings and fins to the long foam tubing (fuselage) and the 2 shorter foam tube

pieces (nacelles), as shown in the illustration on page 30. (* It works best to use hot glue on thewings and fins, as opposed to on the foam tubing, as the hot glue melts the foam tubing.)

5. Roll the paper cones pieces into a cone shape that will fit inside the nacelles and tape shut. Hotglue these to the nacelle, as shown in the illustration on page 30.

6. Tie the rubber band in and through the hole of the washer to “lock” in place.7. Insert the washer/rubber band into the top of the fuselage, letting about an inch of the rubber

band hang out the top (which will become the nose section of the aircraft).8. Pull a cable tie around the nose and cinch it down as tight as possible. Clip the remaining tail

of the cable tie. Put a drop of hot glue on the sharp cut edge of the cable tie to avoid being cutby the sharp edge.

9. To launch, put one thumb in the tail pipe and stretch the rubber band with the other hand andlet it fly!

Summary: This chapter discussed reconnaissance aircraft, albeit unmanned aerial vehicles (UAVs)used for surveillance and reconnaissance. Thus, it was logical to add another fun aircraft to makeand fly, the sR-71 Blackbird, which was unofficially named the “Blackbird.” The Blackbird was de-veloped as a long-range strategic reconnaissance aircraft capable of flying at speeds over mach 3.2and 85,000 feet. The first sR-71 to enter service was delivered in 1966 and was retired in 1990.However, the UsAF still kept a few sR-71s in operation up until 1998, after a few were broughtback to service in 1995. NAsA Drysden’s Center at Edwards AFB, CA flew the sR-71 from 1991until the program was cancelled in 2001. On 15 December 2003, sR-71 #972 went on display at thesteven F. Udvar-Hazy Center in Chantilly, Virginia.

since 1976, the Blackbird has held the world record for the fastest air-breathing manned aircraft.Thus, it is a unique and noteworthy aircraft to continue to share with young people who it is hopedwill take part in the design of future aircraft that can surpass the flying feats of the sR-71. Blackbird.

This is a papercone that is tobe mounted inthe nacelle.

Sr-71 a Blackbird TemplateThe red dashed lines show where to put the hot glue used to bond the tray foam to the black insu-

lation tubing used to make the fuselage.

Note:

Cut both of these

out before the tem-

plate page is glued

to the meat tray.

29

30

Sr-71 Blackbird assembly Diagram

The wing is glued to the fuselage at 90 O to the seam.The outer wing

piece is glued to the foam nacelle.

Cones are glued to the front ofthe nacelle.

DrinkingCup Cone (or cone made from paper)

Rubber Band

Cable Tie

The foam nacelleis glued to the outer edge of the wing.

Outer Wing Piece

C B. Millspaugh

Cinch as tight as possible

31

Learning Outcomes

- Describe how gliders use the environment

to obtain altitude.

- Describe why gliders look different than

powered airplanes.

- Discuss how gliders can achieve great

distances without power.

Important Terms

altitude – the height or distance above a reference plane (The most common planes of referenceused in aviation are heights above sea level and ground level. If it’s above average sea level, it’sreferred to “msL,” or mean sea Level, and if it’s above ground level, it’s referred to as “AGL.”)

convection – fluid motion between regions of unequal heatingdensity – mass in a given volume (example: 12 eggs in a basket)glide ratio – a mathematical relationship between the distance an aircraft will glide forward to the

altitude loss (If an aircraft has a glide ratio of twenty to one, and it is one mile above the Earth, itshould glide 20 miles before landing.)

lapse rate – the average rate at which temperature decreases with an increase in altitude (The aver-age lapse rate is 3 1/2°F per 1000 feet increase in altitude.)

soaring – the art of staying aloft by exploiting the energy of the atmospherestability – the atmosphere's resistance to vertical motionthermal – a column of air that moves upwardstow plane – usually a single-engined airplane that will pull a glider from the ground to an altitude

where it can be releasedwave – a waving action with strong up and down motions started as air moves across mountain

ranges (sailplane pilots can use the motion of this wave to gain altitude.)

22EAA Photograph

RISING AIR CAN MAKE THINGS FLYRising air can have enough energy to provide lift for an aircraft. That's what soaring flight is all

about. Normally, we think of air moving parallel to the Earth and, of course, we call this "wind."

But, there are other factors involved, and one of the most important is the influence that the sun has

upon our environment. From 93,000,000 miles away, the sun provides energy that causes our atmos-

phere to move both horizontally and vertically. The vertical motion provides lifting power for

sailplanes.

When the surface of the Earth gets warmed by the sun, the surrounding atmosphere is heated and

this causes the air to rise. This vertical motion happens because of a change in the density of the air.

As the air becomes less dense, it tends to get lighter and this lighter air wants to rise upward until it

cools. This cooling with an increase in altitude is called the lapse rate. Normally, the temperature

will drop at a rate of 3 1/2° F for every 1000 feet of altitude gained. The Celsius equivalent of this is

2° C per 1000 feet of altitude.

When warm air rises into the colder air at higher altitudes, it cools and then stops rising. After a

period of "hanging around," the air begins to sink back toward the Earth. This up and down move-

ment results in a circulation known as convection. sometimes the atmosphere strongly resists this

convective circulation and is said to be stable.

Two other things happen to air when it is heated; it expands and the pressure drops. Here is an ex-

ample: In early morning, the air is cool due to low overnight temperatures. The molecules are close

together and the atmosphere is more dense when it is cold. When the sun comes up, it warms the

Earth, and this warms the surrounding atmosphere. The molecules start bouncing around at a higher

rate due to heat energy. Because they are bouncing around faster and faster, they spread out. This

means any given parcel of warm air will be lighter than an equal parcel of cold air. As a result of a

decrease in density and a lighter weight, the warm air rises. This upward flow has energy in it and

given enough power, it can lift a flying machine!

32

During daylight hours, the Sun

heats the Earth's surface. Some

areas absorb this energy while

others tend to reflect it back into

the atmosphere. This reflected

energy heats the surrounding

atmosphere and causes rising

columns, or even bubbles of air,

called thermals. It's these thermals

that provide lift for sailplanes.

GLIDERS AND SAILPLANES - Aircraft Designed to Ride the Rising AirWhen the air moves upward, this thermal can provide enough lift and glide ratio to keep a com-

petition sailplane up for hours. By technical definition, a glider is an aircraft that is towed to a certain

altitude and then it glides back to Earth due to the pull of gravity. A sailplane, on the other hand, ac-

tually soars on the energy of the environment. The pilot of a sailplane uses every method possible to

find lift and then to ride the wave to a greater height. (more information about the air environment

glider and sailplane pilots use to their advantage for flight is found in module 3.)

During World War II, the Allies used gliders to haul soldiers into battle. They were towed aloft by

transport airplanes and then released over designated drop zones. Once released from the tow plane,

the skilled glider pilots would try to get the gliders safely back on the ground so the troops could be

in a better combat position. In later wars, the glider was replaced by troop-carrying helicopters and

this proved far more effective in the combat environment.

The United States Air Force Academy Sailplane

It is the dream of many

CAP cadets to someday enter

the United states Air Force

Academy in Colorado

springs, Colorado. One of the

outstanding programs at the

Academy is their sailplane

training and many cadets get

the opportunity to take flight

training in a schweizer TG-4A

sailplane.

The sailplane has dual flight

controls. The flight control sur-

faces are actuated by control

sticks and rudder pedals

through a push rod and cable

system. Aileron and elevator

control is accomplished

through push rods connected to

both control sticks. Rudder

control is accomplished

through cables attached to both

sets of rudder pedals.

The UsAF Academy TG-

4A sailplanes are equipped

with instruments which include

an airspeed indicator, an al-

timeter, a vertical velocity indi-

cator, a sensitive variometer,

and compass.

After being towed to altitude by a powered aircraft, modern sailplanes

are released. The sailplane pilot searches for rising thermals in the at-

mosphere and these provide lift. (Illustration by Dekker Zimmerman.)

Parts of a sailplane

33

34

THE CIVIL AIR PATROL CADET GLIDER PROGRAMThe Civil Air Patrol offers yearly

flight encampments on a nationwidebasis. These are called “Flight Acade-mies” and provide each participatingcadet at least 10 hours of flight instruc-tion with an FAA certificated Flight In-structor. This is called “dual” forone-on-one instruction. Because acadet is eligible by federal aviation reg-ulation to solo a glider at age 14, this isan outstanding entry-level opportunityfor future pilots to acquire important,basic flying skills. Once a cadet hassoloed a glider, he/she can then moveon to powered flight training at anotherencampment. The eventual goal is toachieve the coveted Private Pilot’s Cer-tificate, which allows a pilot to carrypassengers and to fly under visualflight regulations (VFR) virtually any-where within the Continental Unitedstates air space system.

Civil Air Patrol offers all cadets anopportunity to participate in an orienta-tion flight program. This program isdesigned to give each cadet nine flightsduring the course of his/her cadet expe-rience. These flights are flown by CAPsenior (adult) members who meet spe-cific experience and training require-ments as well as through personalbackground clearance standards. Thisis by far the best opportunity for acadet to find out if he/she “really likesflying.” It involves “altitude, attitude,and aptitude.” (see associated Activityseven at the end of the chapter.)

Cadets receive a pre-flight briefing on a CAP Blanik L23 glider.

If you find out you “love it,” you’ll be

hooked for life with the “flying bug!”

Thousands of military, commercial, and

general aviation pilots had their career

start with Civil Air Patrol’s glider

program. Now it’s your turn. If

not already a CAP cadet, contact

www.capmembers.com to find out

how you and your friends can join!

35

22

36

Activity Seven - Zia Glider

Purpose: Build a Zia glider and observe how a glider flies.

Materials: cardstock, hobby knife, ruler, glue, paper clips, a little clay, and glider pattern (cutouts)

on the following page (use this one or a color copy of it)

Procedures:

1. Glue the entire pattern page to the piece of cardstock (a file folder is excellent for this project).

2. Cut out the designs from the attachments.

3. Use ruler to help fold movable parts.

4. Glue the pieces together to build the glider.

5. Fly your glider, experimenting with different positions of the control (movable) parts.

6. Add a small piece of clay to the nose area (experimenting to get the accurate amount) for “stabi-

lization” (better control stability of flight).

Notes: The following recommendations make building a cardstock glider much more successful.

• It is recommended that a hobby knife be used to cut out cardstock models. scissors are accept-

able, but a knife, like the X-Acto® #11, can make more precise cuts. (adult supervision sug-

gested.)

• Use a ruler to score long bends, like the point where the fuselage of the ZIA is folded.

• A high quality white or carpenter’s glue, or spray glue, works well on these models. Be patient,

paper glue takes longer to dry.

• super glue also works, but there’s always the problem of getting your fingers glued together.

Have an adult help when working with super glues.

• All gliders, whether they are cardstock or balsa, usually require a little nose weight to make

them fly. Use the clay for this step, trying different amounts until your glider flies as desired.

Summary: In this activity, cardstock is used to copy a pattern of the Zia Glider and techniques are taught

to put together a quality model and to learn to fly it effectively as a glider. The Zia Glider is a high-wing

design with no dihedral (the upward angle of a fixed-wing aircraft’s wings) and tends to go unstable if the

trim (the cuts and folds for movable parts) is not set exactly. One possible class exercise might include

how dihedral works to make aircraft stable and then problem solve how the airplane design could be mod-

ified to improve stability.

37

Zia Glider Template

cut out straight slot

if you want to give

the wing a dihedral

or cut out curved

slot for a design

with no dihedral

Optional horizontal

stabilizer placements

Depending on your design, you

may want to cut out the “V” notch or

leave the horizontal stabilizer flat

across the trailing edge.

OptiONal

Nose Stiffener

Fold first and glue

into nose.

fold under, glue optional and

cut from leading edge to marks

38

33Learning Outcomes

- Define the principle of buoyancy and how this relates to the flight of a balloon.

- Describe the components of a balloon and how each works in the flight profile.

- Describe the history of the balloon and why it’s recognized as the first powered, manned flight.

Important Terms

altimeter – instrument to provide the height of the balloon above sea level

balloon – an aircraft that uses lighter-than-air gas for its lift, with no built-in means of horizontal

control

burner – the heat source for filling the envelope with hot air

buoyancy – to rise or float on the surface of water or within the atmosphere

crown – the top of the hot air balloon's envelope

envelope – the main body of the balloon, usually made of nylon, that is filled with lighter-than-air gas

gondola – a wicker basket, hanging below the envelope, used to transport passengers and propane

tanks

gore – one of several vertical panels

that make up the envelope

Montgolfier – the name of the two

French brothers who created the

first successful, manned, hot air

balloon in 1783

parachute panel – located in the top

of the balloon's envelope that al-

lows it to be deflated (When a

larger area of deflation is needed,

some balloons are equipped with a

rip panel.)

propane – a lightweight, low carbon

fuel used in hot air balloon burners

thermistor – an instrument which

measures the temperature within the

envelope

variometer – an instrument to deter-

mine the rate of climb or descent;

sometimes referred to as vertical

velocity indicator

BALLOONS WERE FIRSTTwo brothers, Joseph and Etienne Montgolfier, were well-educated Frenchmen who enjoyed re-

searching science and flight. In 1782, after having read scientific papers about the properties of air,they noticed sparks and flames rising in their fireplace. so, they took a small bag of silk, lit a fire un-derneath it, and watched it rise. They soon began experimenting outdoors with larger bags made ofpaper and linen.

In 1783, their earlier experiments led to a demonstration with a balloon. Then, in september 1783,in a demonstration before King Louis XVI and marie Antoinette, they attached to a balloon a cage witha sheep, a roster, and a duck inside. All of the “passengers” were carried aloft and landed safely.

Then on November 21,1783, the first successful manned, powered flight was made in a mont-golfier balloon. Two Frenchmen, Pilatre d'Rozier and the marquis Francois d'Arlandes, flew theirway into history aboard a balloon launched in Paris. The flight lasted about 25 minutes and it landedapproximately five miles from the launch point. The race toward the skies had begun! (Note: TheWright Brothers are credited with the first manned, controlled, powered flight. since hot air balloonscan not be completely controlled, due to the unpredictability of the wind, the Wright Brothers’ statuswas achieved when the brothers made their historic flight December 17, 1903.)

How They Fly

A balloon operates on the princi-ple of buoyancy. It all happens be-cause hot air is lighter, or morebuoyant, than cold air. Imagine thatyou have two parcels of air the samesize. If the air in one parcel is hotand the other is cold, the warm-airparcel will be lighter. If you couldinsert the hot parcel of air inside avery lightweight balloon, it wouldrise into the surrounding colder air.With enough hot air, a balloon willlift not only itself, but passengers,instruments, fuel, and all of theequipment needed for a flight. Thelarge container that holds this hot airis called the envelope. There arestrips of very strong material alongthe vertical length of a balloon thatattach the envelope to the basket.These are known as load tapes.These are also horizontal load tapes,as shown on page 40.

Power for the balloon is providedby a propane burner that quicklyheats the air inside the envelope.The propane, in liquid form, isstored in tanks carried in the basket, called the gondola. When the pilot pulls a cord, the liquid

39

A replica of the Montgolfier balloon is on display

in the US National Air and Space Museum.

40

propane rushes through a series of vaporizing coils and is ignited by a pilot flame at a jet in theburner. During ascent, it is quite common to have temperatures inside the envelope reach 212°Fahrenheit. To get this kind of heat, burners need to produce several million BTU's/ hour. For clarifi-cation, A BTU is a "British Thermal Unit" and by definition it is a measure of heat. It is defined asthe amount of heat required to raise the temperature of one pound of water, one degree Fahrenheit.The metric equivalent of the BTU is a Calorie. A Calorie is the amount of heat required to raise thetemperature of one Kilogram of water, one degree Celsius.

A balloon floats on the wind and directional control is minimal. At various altitudes, wind direc-tion can change and pilots take advantage of this by climbing or descending to get the balloon tochange direction.

The Mathematics Of A Balloon's Lifting Power

In the excellent book, Ballooning, A Complete Guide To Riding The Winds, by Dick Wirth andJerry Young, an explanation is given for the lifting power of a balloon. “Typically, a (hydrogen) gas

balloon will derive about 60 lbs. of lift per 1,000 cu. ft., whereas a hot-air model will develop only

17-20 lb. per 1,000 cu.

ft. (at 100-120 degrees

Celsius). Thus, a

77,000 cu. ft. balloon

will lift: 77 x 17 =

1,309 lbs. gross lift.”

The authors statethat the envelope willweigh about 160 lbs.,the burner and basketwill weigh collectively150 lbs., and four gastanks will weigh 290lbs. This gives a totalaircraft weight of 600pounds. If the balloonhas a gross liftingpower of 1,309pounds, that means itwill carry 709 poundsunder standard condi-tions. Divide 709 bythe weight of an aver-age human at 170pounds and the balloonwill carry 4.17 per-sons, or three passen-gers, one pilot, andsome miscellaneousequipment.

Envelope

Vent Opening

HorizontalLoad Tape

VerticalLoad Tape

Skirt Burner

Basket

Parachute

To ascend, or go up, the pilot lights the burner to create hot air

inside the envelope. To descend, or go down, the pilot can pull down

on the parachute control and this allows hot air to escape out the

vent opening at the top of the envelope, called the crown.

Construction Of A Balloon's Envelope

A large volume of lightweight air is best contained in a sphere. If you study a hot air balloonclosely, as shown on page 40, you will notice that the general shape of the envelope is spherical. Tomake the shape of a balloon, a series of panels are sewn together. These panels are called gores. Thefabric most widely used is nylon and dacron, a form of polyester. There are advantages to both ofthese fabrics. Dacron will withstand higher temperatures, but nylon is lighter and stronger. The fab-rics are coated with polyurethane and other additives to give it longer wear and greater resistance toultraviolet sunlight damage. most fabrics weigh between 1.2 and 2.4 ounces per square yard.

The Basket – A Balloon Pilot's Cockpit

The basket of a balloon is its cockpit. The fuel for the burners is liquid propane and is carriedalong in cylindrical tanks. When the liquid propane passes through the coils on top of the burner, itvaporizes. A small pilot flame ignites the propane and a much larger flame shoots up through theskirt into the envelope.

A balloon pilot's control system is the ascent and descent power of the burner. There is a panel in-side of a hot air balloon thatallows some of the hot air toescape. It's called the para-

chute panel and looks some-what like a conventionalparachute only it fills a holein the top of the balloon,called the crown. This holeis known as a vent. The ventvaries from 6-18 feet across.The parachute is held inplace by cords inside the en-velope. The hot air pressureinside the balloon keeps theparachute in place; however,when the pilot wants to re-lease some of the hot air, acord is pulled which drawsthe parachute downwardthus opening the vent hole.When the cord is released,the parachute is pushed backinto the vent, closing it sothe rest of the hot air is notallowed to escape.

41

42

Cockpit InstrumentationGenerally, the pilot has only three instruments on the instrument panel. One of the most important

is the vertical velocity indicator, or variometer. This gives the pilot an indication of the rate of climband descent. Next, the pilot has an instrument that gives a measurement of the temperature at the topof the balloon and it is known as a thermistor. This is an electronic warning instrument that showsthe pilot when the temperature is dropping and a descent is about to occur. The optimum temperatureinside the crown is around 100 degrees Celsius. Finally, an altimeter is installed that provides theheight of the balloon above sea level.

Flying in a Hot Air BalloonIf you ever have the opportunity to fly in a hot air balloon, do it! This flight is one of the most

peaceful and beautiful flights you’ll ever experience. Being so close to the balloon pilot and the con-trol equipment will enable you to get a very good idea of how the balloon actually flies. Observingthe pilot’s continued attention to both ground and aerial structures, to the need for greater or lesser

altitude, and to the safety inusing the propane tanks willplace you directly in the on-going action of balloon flight. Itis a wondrous thing to behold.(see associated Activity Eight atthe end of the chapter.)

Balloons have priority over all other aircraft in flight when flight plans

have been submitted. If you look under the balloon, you’ll see the

crew in a tiny basket. They’re doing what pilots do best—having fun!

43

33Activity Eight - Hot Air Balloon Purpose: Construct a model hot air balloon and help reinforce the understanding of how a hot airballoon works.

Materials:

- dry cleaner plastic film bags or very thin garbage bag liners (select the type of bag with thethinnest possible plastic and have several on hand. You may have to experiment with bags ofdifferent thicknesses.)

- several small paper clips- cellophane tape- blow dryer (with hot temperature setting)

Safety: If the bag starts to crumple and melt from the heat, setthe blow dryer on a lower setting or hold the bag farther fromthe heat source.

Procedures:

1. seal any openings and tears in the upper end of the bagwith a minimum of cellophane tape.

2. Turn on the blow dryer (or other hot air source). spreadthe bag opening wide to capture the rising hot air whilesupporting the upper end with your hand. It is best tohave assistance in keeping the bag open so that it does notmelt.

3. When the bag is inflated with hot air, test its buoyancy byletting it go for a moment. If it rises quickly, stand backand let it lift. Otherwise, continue heating it for a littlewhile longer.

4. Attach several paper clips to the plastic around the loweropening. Have students experiment with the number ofpaper clips that are needed to keep the balloon from rising too high, but that are needed for theballoon to stay afloat.

5. Release the balloon for its flight. If the bag tips over and spills its hot air before it reaches theceiling, add a few more paper clips to slightly weigh down the bottom. If the bag will not riseat all, remove a few clips.

44

Summary:

Hot air is less dense than cold air. Heat accelerates the motion of the air molecules causing fewermolecules to occupy the same space as a much greater number of molecules do at a lower (cooler)temperature. With fewer molecules, the hot air has less mass, weighs less, and, therefore, is buoyant.

Placing the dry cleaner bag over the heat source captures the hot air and forces out the cooler airin the bag. The bag becomes a mass of low-density air which floats upward in the cooler denser airsurrounding it. The paper clips are placed at the bottom of the bag to keep the open end downward inflight to prevent it from prematurely spilling the hot air and terminating the flight.

As this chapter closes with this last activity, your group may want to build or purchase a largertissue paper balloon to have an outdoor launch. For information about purchasing a hot air balloon,go to Edmund scientific at http://scientificsonline.com or Pitsco at http://catalog.pitsco.com. For information about building and launching a hot air balloon, go to the CAP AE website atwww.capmembers.com/ae. Click on the lessons and other resources box to find the hot air balloon

section which includes full directions for building a tissue paper hot air balloon.

2

Aerospace Dimensions

AIRCRAFT SYSTEMSAND AIRPORTS

2

Aerospace Dimensions

AIRCRAFT SYSTEMSAND AIRPORTS

MODULE

Civil Air PatrolMaxwell Air Force Base, Alabama

2

Aerospace Dimensions

AIRCRAFT SYSTEMS AND AIRPORTS

2

Aerospace Dimensions

AIRCRAFT SYSTEMS AND AIRPORTS

WRITTEN BY

DR. BEN MILLSPAUGH

DESIGN

BARB PRIBULICK

CovER PHoTo

WALT BRoWN, ALBUqUERqUE NM

ILLUSTRATIoNS

PEGGY GREENLEE

EDITING

BoB BRooKS

SUSAN MALLETT

DR. JEff MoNTGoMERY

JUDY SToNE

NATIoNAL ACADEMIC STANDARD ALIGNMENT

JUDY SToNE

PUBLISHED BY

NATIoNAL HEADqUARTERS

CIvIL AIR PATRoL

AERoSPACE EDUCATIoN DEPUTY DIRECToRATE

MAXWELL AfB, ALABAMA 36112

THIRD EDITIoN

JUNE 2013

INTRODUCTION

ii

The Aerospace Dimensions module, Aircraft Systems, is the second of six modules, which com-bined, make up Phases I and II of Civil Air Patrol's Aerospace Education Program for cadets. Eachmodule is meant to stand entirely on its own, so that each can be taught in any order. This enablesnew cadets coming into the program to study the same module, at the same time, with the othercadets. This builds a cohesiveness and cooperation among the cadets and encourages active groupparticipation. This module is also appropriate for middle school students and can be used by teachersto supplement sTEm-related subjects.

Inquiry-based activities were included to enhance the text and provide concept applicability. Theactivities were designed as group activities, but can be done individually, if desired. The activities

for this module are located at the end of each chapter.

CONTENTS

iii

Introduction .............................................................................................ii

Contents...................................................................................................iii

National Academic Standard Alignment ..............................................iv

Chapter 1. Airplane Systems...................................................................1

Chapter 2. Airports................................................................................24

Chapter 3. Airport to Airport - Aeronautical Charts .........................38

A horizontally opposed avco lycoming aircraft engine

iv

National Academic Standard Alignment

Learning Outcomes

- Explain how a reciprocating engine operates.

- Identify parts of the airplane engine when viewed externally.

- Describe how a jet engine operates.

- Identify basic cockpit-mounted powerplant controls.

- Identify basic flight instruments.

Important Terms

combustion - the chemical process of burningcombustion chamber - an enclosed container in which fuel and air are burned for the production of

energycompression - the act of making a given volume of gas smaller cycle - a recurring series of events; the airplane engine has four cycles, intake, compression, power,

and exhaustfuel - a chemical substance which is used as a source of energy; aircraft fuels include gasoline,

kerosene, and propanelean mixture - a mixture of gasoline and air in which there is less fuel and more air magneto - an electrical generator that produces power when rotatedmeter/metering - in terms of fuel for an engine, this is the process of allowing a precise amount of

fuel to pass (An example would be a passageway that allows only so many molecules of gasolineto pass in a given unit of time.)

powerplant - a term which applies to the airplane engine and accessoriesreciprocating - a type of engine that processes air and fuel by a back and forth movement of its in-

ternal partsrich mixture - a mixture of gasoline and air in which there is more gasoline and less air than needed

for normal combustion stoichiometric - a ratio of fuel to air in which, upon combustion, all of the fuel is burned (In energy

terms, it is 15 parts air to 1 part gasoline.) stroke - in the example of an airplane engine, it is the movement of the piston to its limits within the

combustion chamber

1

11

An airplane engine isthe propulsion systemfor the aircraft. It sup-plies the power for theairplane and is called apowerplant when a por-tion of its energy is usedto run other accessories,such as the electricalsystem and cockpit heat-ing and air conditioning.

On the right is a pic-ture of the external com-ponents of an airplaneengine, but what’s onthe inside? The internalcomponents of a recip-rocating engine arementioned in the pictureat the bottom of thepage. A reciprocating

engine is also known asan internal combustion

engine because a fuel mix-ture is burned within theengine. To understand how a reciprocatingengine works, we must take a look at the en-gine’s major parts and their functions.

Every internal combustion engine musthave certain basic parts in order to changeheat into mechanical energy. The cylinderforms a part of the chamber in which the fuelis compressed and burned. An intake valve isneeded to let the fuel/air into the cylinder.An exhaust valve is needed to let the exhaustgases out. The piston, moving within thecylinder, forms one of the walls of the com-bustion chamber. The piston has rings whichseal the gases in the cylinder, preventing anyloss of power around the sides of the piston.The connecting rod forms a link between thepiston and the crankshaft.

2

The external components of a Teledyne Continental 0200 Aircraft Engine

Courtesy of Teledyne Continental

THE AIRPLANE ENGINE

The internal components of a reciprocating airplane engine

3

Cylinder ArrangementsCylinders can be

arranged so that en-

gines may be

mounted in different

airframes. In-line en-

gines are tall and the

nose of the airplane

can be slim for aero-

dynamic efficiency.

The “V” and horizon-

tally opposed in-line

arrangements are

compact and ideal for

small aircraft. The ra-

dial design presents

each cylinder to the

oncoming air for

maximum cooling ef-

ficiency.

Modern Aircraft Powerplant Operation

A modern airplane engine is a device that converts chemical energy into mechanical energy. Air

mixed with gasoline is drawn into a cylinder, then compressed by a piston moving up and down in-

side a combustion chamber. A small bolt of lightning from a spark plug ignites the mixture of fuel

and air and this causes an explosion that drives the piston downward, creating power. The next step

is to get the burned-up gases out of the cylinder. This is done by opening a mechanical “door” called

a valve. This “door” momentarily opens and the piston pushes the gases out past the valve into an

exhaust pipe. The process starts all over again, hundreds of times a minute. This is known as a four-

stroke operating cycle.

The standard configuration for a general aviation aircraft engine is to have four or six cylinders

opposite each other. There are two “banks” of cylinders and this design is called horizontally op-

posed. The opposed engine has a very narrow silhouette and this allows aircraft engineers to design

cowlings, or engine covers, with a low aerodynamic frontal area drag. This shape also allows engi-

neers to install engines on wings with a minimum of drag. The wing-mounted engine is usually cov-

ered with a streamlined enclosure called a nacelle.

Converting Chemical Energy to Mechanical Energy In a reciprocating engine, the piston moves up and down converting air and fuel to energy and ex-

haust. The first stroke occurs when the piston moves downward and simultaneously an intake valve

opens. This is called the “intake” stroke and a mixture of air and fuel is sucked into the engine. A

squeeze, or “compression,” occurs after the intake valve closes and the piston moves upward com-

Most reciprocating engines have one of these four cylinder arrangements.

pressing the mixture of fuel and air. Then when the piston has reached its full upward travel, known

as “top dead center,” a spark ignites the mixture of fuel and air. This is the ignition or “power” phase.

The explosion pushes the piston downward and this energy is then transmitted to the crankshaft,

which in turn powers the propeller. The propeller rotates providing forward thrust. The piston keeps

on going and in a final stroke, pushes the “exhaust” gases out of the cylinder. An exhaust valve

opens simultaneously and the gases are expelled.

Comparing the Reciprocating, Jet, and Rocket EnginesIn both the reciprocating and jet engines, air enters during an intake phase. It is then compressed

by a piston or by a set of compressor fan blades in a jet. The reciprocating engine has a spark plug

for ignition. Once started, a jet engine maintains its combustion by the extremely hot gases. When

the explosion occurs, gases are expelled from both through an exhaust pipe. A rocket, on the other

hand, carries its oxygen with it. As shown in the illustration on the following page, fuel and oxygen

are mixed together and ignited. This provides an enormous amount of power.

4

The four-stroke (5 event) operating cycle of a reciprocating engine: (1) Fuel and air are drawn into the

cylinder during the intake stroke. (2) The fuel/air mixture is compressed by the upward stroke.

(3/4) A spark ignites the mixture forcing the piston downward producing power that turns the propeller.

(5) The burned gases are expelled by the upward stroke.

The Chemistry of PowerBefore getting into the control system that enables a pilot to regulate power to an engine, let’s

look at the “chemistry” of power. An airplane engine is a “heat” engine. It converts heat energy into

mechanical energy, and it is this mechanical energy that turns the propeller. millions of years ago,

the sun provided energy to billions of plants and prehistoric animals, and over long periods of time

their remains have been converted into what we now call “fossil fuels.” When these fossil fuels are

refined into gasoline, it becomes a source of energy for airplane engines.

A mixture occurs when two chemical compounds come together, yet are not chemically com-

bined. Gasoline and air are mixed in the carburetor, but don’t chemically combine until they get in-

side the closed cylinder. In scientific terms, the air molecules do not become part of the gasoline

molecules until they are burned. When they are ignited, a chemical reaction, known as oxidation, oc-

curs and energy is released. That’s what drives the propellers and jet turbines. After this combustion

occurs in the combustion chamber, the gasoline molecules are converted into other compounds like

carbon monoxide, carbon dioxide, and water, and are expelled as exhaust.

One of the most efficient mixtures of gasoline and air is called the stoichiometric ratio. This is 15

parts air to one part gasoline and, theoretically, when ignited, all of the fuel is burned. sometimes,

however, this ratio is not desirable. An example would be during initial engine startup when the out-

side temperature is cold. A rich mixture works better because there is more gasoline and less air. A

lean mixture contains less fuel and more air. A leaner ratio works better after the engine is warmed

up. One problem exists with a stoichiometric mixture. It can get very hot, and over prolonged peri-

ods too much heat can damage an engine. modern engines are designed to operate most efficiently

with a mixture near 12 parts air to 1 part fuel. Pilots can control this in the cockpit with the mixture

control.

5

A comparison of the three most commonly used aircraft engines

Gravity-Feed Fuel System

6

Continental Continental Continental

Venturi

Outside Air

Fuel Tanks

Filler Cap

Primer

Fuel Selector Valve

Fuel Strainer

Main Fuel Line

Primer LineDirect toCylinders

Throttle

Mixture Control

Vent

Main Fuel Line

Filler Cap

Carburetor

Vent

13

24

This is a greatly simplified diagram of a gravity-feed fuel system in a high wing aircraft. stylizedrenderings of only the major parts are shown. Drain valves and plugs, fuel line strainers, interconnectvents, etc. have been deleted for clarification of the system and its function.

The carburetor on an aircraft en-

gine is located on the bottom. Air

is drawn in through the carbure-

tor and passes into the engine

through a series of tubes called

the intake manifold. (Illustration

courtesy of Teledyne Continental)

Fuel-Metering Carburetors To develop the maximum amount of

power, an engine must have the rightmixture of gasoline and air supplied toit during the intake or suction phase.The volume of fuel and air is controlledby the throttle which operates the car-buretor.

A carburetor functions because ofthe lower pressure created when a pis-ton moves down on the intake stroke.When the air is sucked into engine, itcomes in through a tube system and thecarburetor is located between the out-side air and the inside of the engine.

The carburetor has a restriction in itcalled a venturi. This causes air fromthe outside to accelerate as it passesthrough the restriction. A drop in pres-sure occurs inside the venturi and thissucks gasoline out of the carburetor

Intake

manifold

Carburetor

7

into the airflow.There is a small“gate” in the carbu-retor that controlsthe amount of airgoing into it. Thisgate is called thethrottle valve and iscontrolled by thepilot in the cockpit.It is a hand-oper-ated control and it’scalled the throttle.

When the throttleis closed, the throt-tle valve seals thecarburetor. As thepilot pushes thethrottle forward, itopens the throttlevalve in the carbure-tor. The engine isstarted and the pis-tons start moving,creating a suction.The air is sucked in from the outside, and as it passes through the venturi in the carburetor, it speedsup. When this acceleration occurs, the pressure drops and fuel is sucked into the air flow. The air andfuel mixture then travels down into the engine past one of the intake valves. When the intake valveshuts, the trapped fuel and air gets compressed.

Every time a little fuel is sucked out of the carburetor into the stream of air, it has to be replacedor the cylinders will starve. Inside the carburetor, there is a chamber that holds gasoline until it isneeded. This is called the float chamber. There is a float (somewhat like those found in a toilet tank)that monitors the amount of gasoline in the chamber. When the gasoline is drawn into the venturi ofthe carburetor, the float drops. A gate in the float chamber opens and allows gasoline from the fueltanks to fill up the float chamber. Either a fuel pump or gravity is used to get the gasoline from thefuel tank to the carburetor. This force puts pressure on the line and keeps the float chamber suppliedwith fuel.

There is a very important component in the carburetor “system” and it’s known as the carburetorheat. Under certain flying conditions, air passing into a carburetor will form ice in the venturi. Thiscan be dangerous since it can make the carburetor inoperative. If icing chokes the carburetor, the en-gine will quit. To solve this problem, pilots are taught how to use the carburetor heat control so thatit melts the ice. Carburetor heat is made available by using the hot air that surrounds the exhaust sys-tem. When the pilot pulls the carburetor heat control, heated air is channeled into the carburetor. Thiscloses off normal filtered air and directs exhaust-heated, unfiltered air into the carburetor. When thehot air goes through the carburetor, existing ice is melted and the water passes through the engine.momentarily, this creates a problem because hot air is much less dense than cold air. The engine willrun rough due to a fuel/air mixture that is too rich. After the ice is removed, it is proper pilot proce-dure to close the carburetor heat and return to colder air.

A simplified illustration of a carburetor

Powerplant ControlsIn most training airplanes used by the

Civil Air Patrol, there are only two enginecontrols, the throttle and mixture. In air-planes, the throttle is hand-operated and itcontrols engine speed by regulating theamount of air and fuel that flows into itduring the “intake,” or suction phase.

Normally, at sea level, there is a con-siderable amount of oxygen and nitrogenin the air; however, as we climb higherand higher into the atmosphere, the num-ber of air molecules decreases. (Researchhas found that 50% of all of the atmos-phere’s air is located below 18,000 feet above sea level.)

Although the percentage composition of nitrogen and oxygen remains basically the same, theamount of nitrogen and oxygen is less at higher altitudes. As a result of less air (fewer air mole-cules), less fuel is needed. For that reason, a pilot must control the amount of fuel during the suction

phase of engine operation. This is done with the mixture control in the cockpit. It is used to “meter”the amount of fuel available to the carburetor.

ElectricalPower to theSpark Plugs

Electrical energy isrequired to operate ra-dios, lights, and otheraircraft equipment.However, the electricalpower to the sparkplugs is supplied bymagnetos, which areseparate from the air-craft’s main electricalsystem. If a pilot wereto shut off all electricalpower during flight,the engine would con-tinue to operate.

In the early days ofaviation, airplaneswere not equipped with an electrical system, yet the engines had spark plugs that required continu-ous energy. This power was supplied by magnetos. A magneto is an electrical generator that pro-duces power when it is rotated. The airplane’s engine rotates the magneto mechanically and thisproduces the spark for the spark plugs.

The throttle and mixture controls

Twin magnetos are located at the back of the engine

Photo courtesy of Teledyne Continental

8

When watching a movie or video about an early aviation pioneer, you may see a pilot sitting inthe cockpit and someone in front manually spinning the propeller. This procedure has been aroundfor years and is a mechanical method of getting spark to the airplane’s engine. Here’s how it works:The person in front of the airplane spins the propeller; the crankshaft turns and this mechanically ro-tates the magneto. When the magneto turns, electrical energy goes to the spark plugs, and the enginestarts. Once started, the rotation of the crankshaft keeps the magneto going and this supplies thespark plugs with power.

The Electrical Systemmost airplanes are equipped with a 14-28 volt electrical system and the electrical power is sup-

plied by an engine-driven alternator. This component also keeps the battery charged. The battery isespecially important for starting the airplane.

Alternators produce alternating current, which is then converted to direct current. Electrical power issupplied to the bus bar (see schematic on page 10) which distributes this energy to the accessories.

In the cockpit, there is an instrument that monitors the electrical current, or flow, called the ammeter.Another important electrical component in the system, which is located in the cockpit, is the masterswitch. The master switch has to be “on” to engage the starter, and, in the event of an alternator malfunc-tion in flight, the master switch can be turned “off” to isolate the alternator from the rest of the system.

As the schematic shows, there are many circuit breakers and fuses that protect the system fromelectrical overloads. When a circuit breaker “pops,” the electrical power to that accessory is stopped.Resetting the breaker will usually reactivate the circuit; however, if there is still an overload, or anelectrical short, the breaker will continue to pop until the problem is fixed. A fuse, on the other hand,is an electrical device that has a thin metal piece between two metal connections. The thin metalpiece is designed to break when an electrical overload, or short, occurs. Unlike the circuit breaker, afuse must be replaced once the metal connection is broken.

The alternator on an airplane engine looks much like the one on an automobile.

Photo Courtesy of Teledyne Continental

9

That Awesome Jet EngineThe jet engine is a wonderful powerplant and one of its greatest features is reliability. With recip-

rocating engines, you have all kinds of parts moving up and down, in and out, and sideways. But in ajet, there is only one moving part. In the illustration shown on page 11, find the shaft down the cen-ter. Notice that it connects the turbine in the back and both the compressor and fan in front. When thestarter is engaged, this shaft spins. Air is pulled in through the fan section and gets compressed in thecompressor section. Fuel is sprayed into the burner section and ignited. Combustion occurs and thisspins the turbine. The turbine acts like a windmill, capturing the energy of the high velocity hot air.This “windmill” spins the shaft which rotates the fan and compressor in front. The remaining hotgases are expelled through the tail pipe, creating thrust. If you study the artwork provided by Pratt &Whitney on page 11, you can trace the path of air, left to right, through the PW6000 engine.

The Electrical System Schematic

10

ENGINE INSTRUMENTSOne of the most important operations inside an en-

gine is lubrication. This is accomplished by oil, whichallows metal parts to work together. Oil is as importantto an internal combustion engine as blood is to thehuman body. Oil has two primary functions in an en-gine: (1) to lubricate moving parts; and (2) to carryaway heat.

In most training aircraft, a pilot has two instrumentsthat give information about the operation inside theengine. One of the most important is the oil pressuregauge. The oil is circulated through the engine by apump and it is the oil pressure gauge that monitors thisoperation. Close to the oil pressure gauge is the oiltemperature gauge. This allows the pilot to monitor thetemperature and take corrective measures to avoidpossible engine damage due to overheating.

Engine speed is monitored by the tachometer. The“tach,” as it is commonly called, also displays thespeed of the propeller. since the propeller is connecteddirectly to the crankshaft of the engine, changes in thespeed of the engine mean like changes in the speed ofthe propeller.

On the left side, (front), you will see the large fan section. Air enters there, is compressed (blue) in the

compressor section and ignited in the burner section (yellow). This spins the turbine (red) and part

of this energy is used to turn the center shaft. The rest is expelled out the tail pipe (in rear) as thrust.

(Artwork of PW6000 engine courtesy of United Technologies, Pratt & Whitney Division)

The temperature and oil pressure

gauges in the cockpit

The tachometer, displaying engine

speed in revolutions per minute

11

FLIGHT INSTRUMENTS There are special instruments that allow

the pilot to monitor an airplane’s operationin flight. Three of these work on the princi-ple of differences in pressure, also knownas pressure differential. The other threework on the principle of gyroscopes, main-taining their position while spinning.

To more clearly understand these instru-ments, let’s first examine pressure differen-tial. Think of a parcel of air, one squareinch (about the size of a postage stamp),and 50 miles tall. If you could somehowweigh that space of air anywhere in theworld, it would average 14.7 pounds. Ifyou could take weight samples at variouslevels, up to the top of the parcel, the airwould weigh progressively less, and, at thetop, it would be virtually weightless.

What does this have to do with altitudemeasurement in an airplane? If the pres-sure becomes progressively less as we gohigher above the Earth, we can use it togive us precise height information. Thinkof it this way; if you had an ultra-sensitivepressure gauge, you could get an accuratereading of the altitude gained by going up-stairs in a house, or a school, or even up ona chair.

Engineers who build airplane instru-ments have a set of standard referencesbased on information that scientists havegathered. There are standard references forpressure, temperature, etc. For pressure, atsea level, the standard is 29.92 inches ofmercury, or 1013.2 millibars. This meansthat our 50 mile-tall column of one squareinch of air would cause a mercury barome-ter to stand 29.92 inches tall. As stated ear-lier, when we go higher in altitude, the airweighs less and the pressure drops. scien-tists found that the average pressure drop,for every 1000 feet of altitude gained, is oneinch. see the diagram to the right. (It mustbe noted that the element mercury is dan-gerous, and only a trained and highly-quali-fied scientist should experiment with it.)

This line representsthe top of the earth's atmosphere (50 milesabove the surface).

A parcel of air1 square inch at the bottomand reachingto the top of the atmosphereweighs 14.7 pounds.

Approximately 1/2 ofthe earth's atmosphereis located below18,000 feet.

1 square inch of air at sea level

The weight of the air upon every square inch of the Earth’s

surface is approximately 14.7 pounds at sea level and

decreases to nearly zero at 50 miles above the surface.

12

A Torricelli

barometer is a

glass tube filled

with the ele-

ment Mercury.

The open end

of the glass

tube is placed in a bowl of Mercury. The pressure of the at-

mosphere pushing down on the surface of the Mercury, and

the vacuum inside the glass tube, will give a measurement of

changes in atmospheric pressure. On a standard day at sea

level, this column of Mercury rises to 29.92 inches tall. The

metric equivalent of that is 1013.2 millibars.

Hg

1013.2 Millibars 29.92 Inches

The Altimetersince pressure is related to altitude, we are able to tell how

high we are by monitoring the pressure in an airplane com-pared to a pressure reference on the ground or at sea level.That is how altimeters work. Just before take-off, a pilot setsthe altimeter to the local pressure. Then as the airplaneclimbs, the pressure begins to drop. The altimeter senses thischange and displays it as altitude.

The Vertical Velocity IndicatorWhen the airplane levels off at a given altitude, and the

pressure stabilizes, another instrument reads this as zero. Ifthe airplane goes up or down from this point, the instrumentsenses the change and gives the pilot a rate of climb, or as-cent. This instrument is known as the VVI or Vertical Veloc-ity Indicator. You may also hear it referred to as the “rate ofclimb.”

The Airspeed IndicatorAnother very important instrument records the difference

between still air (static) and air that is being rammed into thesystem. Compared to a car, it is the airplane’s “speedometer.”In the language of instruments, it is called the airspeed indi-cator. Outside, usually located on a wing, is a small, hollowtube called the pitot. As the airplane moves forward, the rela-tive wind flows into the pitot tube and this creates a rammingeffect that is registered as pressure. When this ram air is com-pared to still air, it can be displayed as speed. The differencebetween the ram air and the still air gives what is known as apressure differential. A static port provides the system withinformation from an area of undisturbed air.

Indicated airspeed is the information you get when you

read the airspeed indicator, directly. Another, known as the

calibrated airspeed, is the indicated airspeed corrected for er-

rors that may occur in the instrument itself. The next kind of

The Pitot Static System Schematic

13

The all-important airspeed indicator

The vertical velocity indicator displays

a rate of change in altitude

The altimeter measures pressure and

displays this as height above sea level

airspeed is known as true. True airspeed is the actual speed of the airplane through the air. This kind

of airspeed is corrected for pressure and non-standard temperature. In “language” terms, pilots will

say, “...my airplane trued out at 180 knots.” It means that after adjusting the airspeed indicator, at a

given altitude, the airplane is traveling at 180 knots. Finally, there is the speed over the ground. This is

referred to as ground speed and can be calculated by the time it takes for the airplane to fly between

two or more points on the ground. For your information, a regular mile is known as a statute mile and

is 5,280 feet long. A nautical mile, often referred to as a “naut,” or “knot,” is 6,076 feet.

Flight Instruments-Gyro Power

These instruments are based on the principle of a spinning gyroscope. The gyroscope has a small

rotating wheel, called a rotor, that is mounted on an axle. The rotor will maintain its position in space

while spinning at a very high speed. This principle is called rigidity in space and means that once the

rotor starts to spin at high speed, it strongly resists changes and forces applied to it. As long as it re-

mains in one place, and the rotor spins, it will give the pilot valuable information about direction,

banking, and attitude. Note that the gyro is mounted in two rings, called gimbal rings. These rings

allow the gyro to rotate freely, or universally. By various methods of mounting, gyros are an energy

source in three very important flight instruments: alitude indicator, heading indicator, and turn

coordinator.

Let’s take a look at the gyroscope as an “experiment.” A toy gyroscope (gyro for short) can be made,

but it is much more convenient to buy one at a hobby, craft, or toy store. Here’s how they work: A

string is first inserted into a hole in the gyro’s axle. The string is wound tightly around the axle. A hard

pull on the string will spin the axle at high speed and that’s when Newton’s First Law of motion takes

over. This law states, “a body at rest will remain at rest unless acted upon by some outside, unbalanced

force, or a body in motion will remain in motion unless acted upon by some outside, unbalanced

force.” Now, when it’s spinning you can actually balance the gyro on the tip of a pencil! Amazing, but

true! If it is standing up, that’s the principle behind the airplane’s attitude indicator; if it is on its side,

14

A toy gyroscope shows how it can maintain its position while spinning. When the

rotor is spinning perpendicular to the surface, it is parallel to the horizon.

The attitude indicator is based on this principle. It gives the pilot an “artificial horizon.”

and the rotor is spinning perpendicular to the surface, that’s the principle behind the airplane’s heading

indicator and turn coordinator.

If a rotor is aligned vertically, it can give direction information. Imagine that the airplane is sitting

on the ground with its nose pointed north. When the airplane is started, the rotor starts to spin. No

matter what direction the airplane goes, the rotor will continue to spin still aligned to north. This is

the basis of a heading indicator, an instrument also known as the “directional gyro.”

The heading indicator can be set without the airplane facing north. An example of this may be

that the airplane is headed west when the engine is started. The pilot rotates a small knob on the face

of the instrument so that it shows west, or 270 degrees. The instrument is now automatically cor-

rected for all other headings. The pilot uses a precision magnetic compass, located usually above the

instrument panel, for these corrections. (see associated Activity One at the end of the chapter.)

Also displayed with the turn coordinator is a

simple instrument called an inclinometer. This is

nothing more than a curved, liquid-filled glass tube

with a ball inside. If a turn is not being executed

properly by the pilot, the ball will give a clear indi-

cation of poor technique. If the banking maneuver is

done properly, the ball will stay in the center

throughout the procedure. The inclinometer shows

whether the airplane is slipping or skidding in a

turn. slipping means that the airplane is moving to-

ward the inside of the turn and skidding means it's

moving away from the radius of the turn.

15

Once a vertically-mounted rotor starts to spin, it tends to stay in that alignment.

The heading indicator becomes an artificial compass and gives the pilot directional information.

The turn coordinator uses the gyro

principle for banking information.

THE GLASS COCKPIT – A New Generation of Aircraft Instrumentation

This image gives you a closer look at the Captain’s panel of a Cessna 172 airplane. The display infront of the pilot is referred to as the PFD, or Primary Flight Display. The upper ADI, or Attitude Di-rector Indicator, is bracketed on the left by the “speed Tape” Indicator and on the right by the “Alti-tude Tape” Indicator. The bottom half is the Horizontal situation Indicator and shows a full compassrose presentation with a terrain mode overlay.

What is a “Glass Cockpit?”A glass cockpit is an airplane cockpit that features electronic instrument displays. The glass cock-

pit has become standard equipment on most aircraft today, including airliners, military aircraft, andgeneral aviation aircraft. The glass cockpit was even fitted on several of the recent space shuttles.

Aircraft used to rely on mechanical gauges, but over the years as more instruments and controlswere added, the cockpit became very crowded. The growing number of instruments competed forspace and the pilot’s attention. The introduction of electronic displays and digital informationchanged that. The glass cockpit represented a huge technology update and an improvement.

The glass cockpit displays the information in an easily understood picture of the aircraft situationand position. It does this, not only in horizontal and vertical dimensions, but also in regard to timeand speed. The glass cockpit reduces the pilot’s workload and at the same time gives the pilot situa-tional awareness. The multi-colored, multi-functional flat screens are much easier to read and under-stand. The glass cockpit has improved pilot efficiency and airplane safety.

NAsA, the aerospace industry, and the Department of Defense are all using glass cockpit technol-

16

17

ogy to increase performance of their aircraft and the pilots who fly them. Additionally, both airlinesand passengers are benefitting from this new technology. The cost of travel is less than it would bewith the old technology and more flights arrive on time.

Future DevelopmentsThe newest developments in cockpit displays look and behave a lot like other computers, with

windows and data that can be manipulated with point-and-click devices. They also add terrain, ap-proach charts, weather, vertical displays, and 3D navigation images.

The improved concepts enable aircraft makers to customize cockpits to a greater degree than waspreviously done. All of the manufacturers involved have chosen to do so in one way or another—such as using a trackball, thumb pad, or joystick as a pilot-input device in a computer-style environ-ment. many of the modifications offered by the aircraft manufacturers improve situational awarenessand customize the human-machine interface to enhance safety.

As aircraft displays havemodernized, the sensors thatfeed them have modernizedas well. Traditional gyro-scopic flight instrumentshave been replaced by Atti-tude and Heading Referencesystems (AHRss) and AirData Computers (ADCs),improving reliability and re-ducing cost and mainte-nance. (GPs) receivers arefrequently integrated intoglass cockpits.

modern glass cockpits

The glass cockpit of a Cessna CJ2 Citation – Image by Alex McMahon

Glass cockpit of a Piper Saratoga

18

might include the synthetic Vision system (sVs) or the Enhanced Vision system (EVs). syntheticVision systems display a realistic 3D depiction of the outside world (similar to a flight simulator),based on a database of terrain and geophysical features in conjunction with the attitude and positioninformation gathered from the aircraft navigational systems. Enhanced Vision systems add realtimeinformation from external sensors, such as an infrared camera.

All new airliners, such as the Airbus A380, and Boeing 787, as well as private jets, such as Bom-bardier Global Express and Learjet, use glass cockpits. Certain general aviation aircraft, such as the4-seat Diamond Aircraft DA40, DA42, and DA50, and the 4-seat Cirrus Design sR20 and sR22, areavailable with glass cockpits. systems, such as the Garmin G1000, are now available on many newGeneral Aviation (GA) aircraft, including the classic Cessna 172, one of CAP’s two major airplanesused for aviation missions. The other major CAP airplane, the Cessna 182, has a glass cockpit.

Glass cockpits are also popular as a retrofit for older private jets and turboprops, such as DassaultFalcons, Raytheon Hawkers, Bombardier Challengers, Cessna Citations, Gulfstreams, King Airs,Learjets, Astras, and many others. Aviation service companies work closely with equipment manu-facturers to address the needs of the owners of these aircraft.

GPS – A NEW TECHNOLOGY FOR AEROSPACE NAVIGATION

GPS – Where Did It Start?The Global Positioning system (GPs) is a navigation and

precise-positioning tool. Developed by the Department of De-fense in 1973, the GPs was originally designed to assist sol-diers and military vehicles, planes, and ships in accuratelydetermining their locations world-wide. Today, the uses of theGPs have extended to include both the commercial and sci-entific worlds. Commercially, the GPs is used as a navigationand positioning tool in airplanes, boats, cars, and for almostall outdoor recreational activities such as hiking, fishing, andkayaking.

In the scientific community, the GPs plays an importantrole in the earth sciences. meteorologists use it for weatherforecasting and global climate studies. Geologists can use it asa highly accurate method of surveying and in earthquake stud-ies to measure tectonic motions during, and in between, earth-quakes.

How Does It Work?Three distinct parts make up the Global Positioning system. The first segment of the system con-

sists of 24 satellites, orbiting 20,000 km above the Earth in 12-hour circular orbits. This means that ittakes each satellite 12 hours to make a complete circle around the Earth. In order to make sure thatthey can be detected from anywhere on the Earth's surface, the satellites are divided into six groupsof four. Each group is assigned a different path to follow. This creates six orbital planes which com-pletely surround the Earth.

These satellites send radio signals to Earth that contain information about the satellite. Using GPsground-based receivers, these signals can be detected and used to determine the receivers' positions

The GPS is a “constellation” of

satellites that orbit the earth.

19

(latitude, longitude, and height).The radio signals are sent at twodifferent L-band frequencies. L-band refers to a range of frequen-cies between 390 and 1550 mHz.Within each signal, a coded se-quence is sent. By comparing thereceived sequence with the origi-nal sequence, scientists can deter-mine how long it takes for thesignal to reach the Earth from thesatellite. The signal delay is use-ful in learning about the Iono-sphere and the Troposphere, twoatmospheric layers that surroundEarth's surface. A third signal isalso sent to the receivers from the

satellite. This signal contains data about the health and position of the satellite. The second part of the GPs system is the ground station, comprised of a receiver and antenna, as

well as communication tools to transmit data to the data center. The omni-directional antenna at eachsite, acting much like a car radio antenna, picks up the satellite signals and transmits them to the sitereceiver as electric currents. The receiver then separates the signals into different channels desig-nated for a particular satellite and frequency at a particular time. Once the signals have been isolated,the receiver can decode them and split them into individual frequencies. With this information the re-ceiver produces a general position (latitude, longitude, and height) for the antenna. Later, the datacollected by the receiver can be processed again by scientists to determine different things, includinganother set of position coordinates for the same antenna; this time with millimeter accuracy.

The third part of the system is the data center. The role of the data center is two-fold. It both mon-itors and controls the global GPs stations, and it uses automated computer systems to retrieve andanalyze data from the receivers at those stations. Once processed, the data , along with the originalraw data, is made available to scientists around the world for use in a variety of applications. sinceglobal GPs sites are constructed and monitored by different institutions all over the world, there aremany different data center locations.

The Global Positioning system (GPs) was designed as a dual-use system with the primary pur-pose of enhancing the effectiveness of U.s. and allied military forces. GPs is rapidly becoming anintegral component of the emerging Global Information Infrastructure, with applications rangingfrom mapping and surveying to international air traffic management and global change research. Thegrowing demand from military, civil, commercial, and scientific users has generated a U.s. commer-cial GPs equipment and service industry that leads the world. Augmentations to enhance basic GPsservices could further expand these civil and commercial markets.

The GPs is managed by the National space-Based Positioning, Navigation, and Timing (PNT)Executive Committee, supported by the PNT Executive secretariat (http://www.pnt.gov). The PNTmanages GPs and Us Government augmentations to the GPs, consistent with national policy, tosupport and enhance Us economic competitiveness and productivity while protecting national secu-rity and foreign policy interests.

The basic GPs is defined as the constellation of satellites, the navigation payloads which producethe GPs signals, ground stations, data links, and associated command and control facilities which are

The Earth and its layers

thermosphere

troposphere

mesosphere

stratosphere

atmosphere

ionosphere

lithosphere

asthenosphere

mantle

mantle

core

crust

crust

20

operated and maintained by the Department of Defense; the standard Positioning service (sPs) asthe civil and commercial service provided by the basic GPs; and augmentations as those systemsbased on the GPs that provide real-time accuracy greater than the sPs. The GPs permits land, sea,and airborne users to determine their three dimensional position, velocity, and time, 24 hours a day,in all weather, anywhere in the world.

The GPs is one technology that allows pilots to accurately determine their position anywhere onthe Earth within seconds. The GPs is becoming the primary means of navigation worldwide. TheGPs units in the aircraft finds the nearest two satellite signals. This process is called “acquisition.”The time it takes for the signals to travel creates a precise triangle between the two satellites and theaircraft, telling the pilot his latitude and longitude to within one meter.

Despite these advances, pilots can still crash becausethey get lost or lose track of hazards at night or in badweather. On December 29, 1970, the Occupationalsafety and Health Act came into effect. It requires mostcivilian aircraft to carry an emergency locater transmit-ter (ELT). In the event of an accident, an ELT is de-signed to transmit a distress signal and then leadrescuers to the site. The ELT becomes active when apilot tunes to an emergency radio frequency or acti-vates automatically when the aircraft exceeds a certainforce in landing, called the g-force, during a crash. (seeassociated Activity Two at the end of the chapter.)

One of 24 Global Positioning Satellites – Image courtesy of NASA

Emergency locater transmitter

21

Activity One - Gyroscope: Earthly Spinning Purpose: After discussing the use of the gyroscope in airplane instrumentation, this activity willdemonstrate how the gyroscope works within the force boundaries of Earth, and what principle oc-curs when the gyroscope is spinning.

Materials: Acquire a toy gyroscope from a hobby, craft, or toy store. The cost is around $5.00. (sci-ence museums are also usually a good place to locate one, as well as the internet.)

Procedure:

1. Run the gyroscope’s string through the hole in the gyroscope rotor's axle.

2. Wind the string onto the axle.

3. Holding the gyroscope, pull the cord with a steady but strong motion.

4. Once the rotor starts spinning, let the gyro rest on its stand.

5. Touch the upper part of the gimbal rings and notice how it wants to stay in position.

6. Let it spin down or stop it with your fingers.

7. Repeat the steps 1-3 and see how many places a gyro will maintain its position, even continuing towork sideways. With careful placement, the gyro will sit on a pencil point!

Summary: Newton’s First Law of motion applies here. This law states: “a body at rest will remainat rest unless acted upon by an outside, unbalanced force, or a body in motion will remain in motionunless acted upon by an outside, unbalanced force.” On Earth, gravity acts on the gyro. But, inspace, without the forces found on Earth, the gyroscope will spin endlessly. Thus, a spinning gyro-scope could help demonstrate the principle of rigidity in space, which means that once the gyro isspinning at a high speed, it resists change.

11

The principles of a gyroscope are amazing

22

Activity Two - Geocaching

Purpose: To introduce students to a fun reading, geography, math, and technology activity using theGlobal Positioning satellite (GPs) technology available for use in the aviation and space programs.

Materials: computer with internet to access informa-tion from the Geocaching website http://www.geo-caching.com/, which includes information on wherecaches are located; a GPs; note pad; pen or pencil;drinks; and first-aid kit for trip; bug spray; walkingstick (optional depending on terrain); small items touse as trade items in the located caches (such as mar-bles, keychains, special coins, or other significantitems);

Procedure:

What is geocaching? Geo stands for Earth and cachestands for container. Geocaching is a high-tech treas-ure hunting game played throughout the world by ad-venture seekers equipped with handheld GPsdevices. The basic idea is to locate outdoor hiddencontainers, called geocaches, and then log your findand experiences online. Geocaching is enjoyed bypeople from all age groups, with a strong sense ofcommunity and support for the environment.There are hundreds of thousands of registered geo-caches hidden around the world. One of the big sur-prises is how many geocaches there are in virtuallyall vicinities (some even in the places people regu-larly walk their dogs). This would be a great way toenliven a long boring car journey, adding extra inter-est to a unit or school field trip.

Follow the guidance below.1. Give yourself or your team a name to use online at geocaching.com and to log your find at the

cache location.2. While online select and print at least one cache you want to find by searching the zip code of the

desired area. You may want to select a cache with a larger container size in hopes of being able totrade items for your group.

3. Read your selected cache description, checking cache size and terrain. You can pull up the gogglemap to get a general idea of the area where it is located. Caches can be in parking lots or deep inthe woods. Print out your selected cache page information and take it with you.

4. Use the coordinates given by the hider to find the cache. Put these coordinates in your GPs an hitgo on the GPs.

5. Once you arrive, use stealth in finding the cache. Not all people are in the game. You don’t want

This find was a larger size container in the

woods. The kids enjoy the trade items

and the log gets signed.

23

others seeing you find the cache or they may not respect the game and may move it or take it. Useyour GPs to get as close to the exact location as you can. Hopefully this will bring you within 10feet or closer.

6. start your hunt. The cache can be a large Tupperware container full of fun trade items hiddenunder branches or it can be a small magnetic cache stuck on something metal so small it onlyholds a small piece of paper to sign. many are very creative and are something you would neverthink was even a container.

7. Inside the cache is a log. Enter your cache name on the log so you can show that you have foundit. The first cacher to find a newly published cache gets “first to find” (FTF)honors. And will sign the log FTF. Others might put TFTC which means“thanks for the cache”.

8. Use your paper to make any notes to describe your find and to record back atyour computer. You will log it as a “find” and get a smiley or a “did not find”(DNF) and maybe a fun story about your adventure without giving informa-tion about what the container was or the exact location. It takes the even themost experienced geocacher a few times to find some of the harder ones, sodon’t get discouraged.

9. Larger cache containers often have small trade items. If you take somethingit is nice to leave something for the next person to enjoy or use for trade. Youmay find a geocoin or travel bug (which are trackable items described on thewebsite). If you take one, you must find another cache to leave it in and logwhere you moved it to on the website. The owner has written a mission orgoal and watches its movement online.

Summary: This activity familiarizes you with a GPs. some GPss have geo-caching programs so you can read the information while you are geocaching.

This Geomate Junior

Geocaching GPS is

great for kids.

But any GPS

can be used.

Learning Outcomes

- Explain the basic layout of a general aviation airport.

- Identify taxiway and runway signs and markings.

- Explain the role of the Federal Aviation Administration in controlling air traffic.

- Identify the different phases of the flight profile.

- List the phonetic alphabet.

Important Terms

ATC - air traffic control

beacon - a tower-mounted, large, rotating light located at an airport that gives pilots a guide to thetype of airport and the airport’s location

controlled airport - an airport with an operating control tower

control tower - a structure that houses air traffic controllers

24

During the last week in July and the first week in August, Wittman Field,

in Oshkosh, Wisconsin, becomes the busiest airport in the world.

This occurs during the annual Experimental Aircraft Association (EAA) fly-in called AirVenture.

22

25

course - the intended path of flight, which is measured in angular degrees from true or magneticnorth on a compass

FAA - Federal Aviation Administration, which is the regulatory authority for all aviation

flight profile - a standardized series of steps the pilot takes from take-off to landing

FSS - Flight Service Station - a FAA facility that provides pilots with weather briefings and flightplanning (opening and closure)

heading - the direction that an airplane points with respect to true, or magnetic, north including anywind displacement; based on its longitudinal axis

noise abatement - a policy set forth by a governing body that controls the noise impact upon a com-munity surrounding an airport

ramp - the airport’s “parking lot”

runway - a dedicated pathway for taking off and landing airplanes

runway heading - a number labeling a runway, which is based on corresponding degrees from true,or magnetic, north

segmented circle - a set of indicators, usually surrounding an airport’s wind sock, that provide traf-fic pattern information to a pilot in the air

taxi - ground movement of an airplane

taxiway - a passageway between the parking area and the runways of an airport

tetrahedron - a device that gives an indication of the landing direction at an airport

traffic pattern - a rectangular virtual path above an airport that facilitates the coordination of theflow of aircraft in the air

uncontrolled airport - an airport without an operating control tower

wind direction indicators - several types of devices that give a pilot an indication of wind direction

wind sock - a fabric tube that shows which direction the wind is from

Naples, Florida Airport – Images by Alex McMahon

THE FLIGHT PROFILEThere are basically two kinds of

airports, uncontrolled and con-

trolled. An airport can be a smallgrassy field, located in a pasture, orit can be a large center for commer-cial or military aviation.

When an airplane departs an air-port, large or small, it normally fol-lows a standard flight profile.Whether it’s a Piper Cherokee witha student pilot at the controls or aLockheed SR-71 on a routine mis-sion, it follows basically the sameprocedure every time. Refer to theillustration below to follow thelisted profile:

(A) While the airplane is parked, the pilot walks around and examines it externally. This is calledthe preflight inspection. Fuel & oil levels, control surface freedom-of-movement, flaps check andlanding gear condition are just a few of the many important items a pilot examines before startingthe airplane.

(B) Using the example of a controlled airport, the pilot gets movement clearance from the groundcontroller in the airport control tower. This is the taxi phase of the profile. The pilot taxis the air-plane along a taxiway and then stops before entering a runway.

(C) The pilot sets the parking brake, does an engine run-up, checks magnetos, sets mixture,checks carburetor heat, checks engine instruments, checks flight instruments, and makes sure that allflight controls are moving properly. Passengers are briefed, seat belts and shoulder harnesses arechecked, and the pilot calls the control tower for clearance to take off.

(D) Once cleared by the tower controller, the pilot enters the runway and the takeoff portion ofthe flight profile begins.

(E) After takeoff, the pilot puts the airplane into the climb portion of the profile. During this pe-riod, the air traffic controller may ask the pilot to follow a specific traffic pattern. Once clear of theairport traffic, the pilot may continue climbing until a desired altitude is reached.

(F) The pilot then levels off and the aircraft enters the cruise part of the profile. Depending uponpreflight planning, the pilot may elect several options for the rules that govern flying. An example ofthis is VFR, or Visual Flight Rules. If the pilot elects to go from point to point using these rules, all

26

Not all airports are acres of concrete and asphalt.

In many parts of the world, grassy fields are home

for airplanes like this Australian Tiger Moth.

The flight profile-from takeoff to touchdown

h indicates complete stops

27

movement is done on a “see and be seen” basis. A very important part of learning to fly an airplaneis knowing where you can and can not go when flying by the rules. Visual Flight Rules are directlyconnected to weather and visual conditions within the airspace system. A pilot may elect to go byIFR, or Instrument Flight Rules, wherein the pilot uses the instruments to guide flight. IFR are usedin poor visibility conditions, such as bad weather or darkness. In either case, the pilot must first betrained in and rated by the Federal Aviation Administration (FAA). Unlike VFR, IFR is a systemof carefully-controlled directions and altitudes that enables the pilot to fly into weather conditionswhere visibility is limited. Under these rules, strict control is maintained by Air Traffic Controllerswho monitor the system by radar, and IFR requires that a pilot fly an airplane with great precision.

(G) The next phase from cruise is descent. In this phase, the pilot decreases altitude and preparesfor landing at another destination, or returns to the airport where the flight originated. If the pilot isapproaching a controlled airport, radio contact must be made with the air traffic control tower, or anATC radar facility called “approach control.” The controller will then direct the pilot to position theairplane on a specific course so that it enters the airport without disrupting the existing flow of traf-fic.

(H) Once the pilot enters the proximity of an airport, a traffic pattern is followed in preparationfor landing. This is all part of the approach-to-landing phase.

(I) The next step is landing. Once the pilot has positioned the airplane into alignment with therunway, a glide slope angle is maintained until touchdown. The object is to get the airplane to landstraight ahead at a relatively slow speed. most flight training schools teach pilots to land just abovestall speed. This puts the least amount of stress on the airplane and does the least damage to tires.The pilot slows the airplane down and exits the runway onto a taxiway.

(J) The airplane is then stopped and the pilot contacts the ground controller for permission to con-tinue on a taxiway to a parking spot on the ramp. Once cleared, the pilot taxis the aircraft to the park-ing area.

The airport traffic pattern

(K) The pilot positions the airplane at or near the tie-down chains and the airplane is shut down. Apost-flight procedure is followed including shutting everything off properly and recording the flight inthe necessary log books.

RUNWAY MARKINGSThe Federal Aviation Administration controls the airway system over the United states and it has

certain standards that govern airports. These standards are quite different from the familiar automo-bile street, avenue, boulevard, and freeway markings.

several factors are taken into consideration when airport designers are in the planning stages. Ifthere is to be only one runway, careful consideration is given to the prevailing winds surrounding theairport. since wind is a major factor in the takeoff and landing performance of an airplane, airportdesigners try to position a runway so that pilots will be taking off and landing into the wind most ofthe time.

The numbers at the ends of the runways are actually shortenedheadings as noted on a Compass Rose. (see photo to the right.)

Runways are given numbers between 01 and 36. This indicates therunway heading. A runway with the number 36 point to the north, at“magnetic north,” or “true north,” which is 360°.

A runway with the number 18 is south, or 180°, which is actually180° clockwise from magnetic north on a compass.

Thus, the runway number is one tenth of the runway’s magneticheading. In other words, a runway with a 270° will be recorded as 27(the zero is dropped to denote one tenth of the actual heading). Look-ing at the Compass Rose photo to the right, in what direction would a270° (or runway 27) be headed? Yes, it would be west. Look at 290°(or runway 29). In what direction would that runway be headed? Youwill see WNW on the compass, and that means West North West.

Looking at the runway image above, imagine that you are in the cockpit of an airplane coming infor a landing. When you look out, you see runway 29 directly ahead. If you were to glance at the air-plane’s compass, you would note that it also reads 29 (the shortened, or one-tenth version of 290°).Now, if you were to come into the same airport from the opposite direction, you would see the num-ber 11 on this runway. Again, a glance at the compass would show the number 11, the magneticheading of 110° . In what direction is runway 11’s course ? The compass says EsE, which meansEast south East, which is the opposite direction of runway 29- WNW.

Often there will be two parallel runways (runways running side-by-side with the same magneticheading). Their numbers will be the same at both ends. In this case, they are designated “R” for theright one and “L” for the left one. Using the “20” above, you would see 29R on one runway and 29Lon the other. If three runways are in parallel, the center would be 29C (for center).

28

29

11

A typical VFR runway where the numbers "29" and "11" are based on magnetic headings of 290° and 110°

Compass Rose

29

Nonprecision Instrument Runways

some airports have the capability to conduct nonprecision instrument approach operations duringinclement weather. Nonprecision runways only provide pilots with lateral (left or right) or alignmentmarkings to help the pilot land. There are no markings to determine vertical (altitude) or glide angleand the pilot has to rely on instruments for this information. At airports where they have this instru-ment landing capability, you may see nonprecision instrument markings, as in the illustration below.These threshold markings are the two sets of four stripes ahead of the number 36.

All the Bells and Whistles-Precision Instrument Runways

If an airport is an important hub in the airway system,it will usually have a runway that is designed to acceptaircraft under bad weather conditions. This type of run-way is in full compliance with IFR, or Instrument FlightRules. When a pilot is in the approach phase of the flightprofile, he/she will use an electronic “Instrument Landingsystem” (ILs) glide slope instrument in the cockpit forguidance to a precision runway.

A precision runway has both lateral (left to right) andvertical (altitude) informational markings to assist thepilot in precise alignment (lateral) and glide angle (verti-cal) control.

since the pilot often cannot see the runway, the visualmarkings, shown to the right, assist in getting the airplaneonto the runway safely.

36

18

500'

3000'

1000'Aiming Point

TouchdownZone Marker

Side Strips

ThresholdMarkings

UnusablePortion

1836

Nonprecision instrument runway

Precision instrument runway

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Airport signs

AIRPORT SIGNSAt some point, it is hoped that you will get the opportunity to go on an orientation flight. When

the pilot is taxiing out for departure, you will notice signs along the route and near the runway. Part

of the “language” of an airport is understanding the meaning of these signs. The six categories of

signs are depicted below and are described on next page.

31

1. Mandatory Signs - These have a red background with white numbers/letters. These signs denotean entrance to a runway, critical area, or a prohibited area.

2. Location Signs - These are black with yellow inscription and usually a yellow border. They don’thave arrows. They are used to identify a taxiway or runway location, boundary of the runway, oran instrument landing system (ILs) critical area.

3. Information Signs - These are yellow signs with black lettering and symbols that give informa-tion on such things as areas that cannot be identified by the tower, noise abatement procedures,and applicable radio frequencies.

4. Direction Signs - These are yellow signs that give a pilot directions. The black inscription andarrow identifies the designation of the intersecting taxiways leading out of an intersection.

5. Destination Signs - These are yellow signs with black letters and a distinctive black arrow, likethe direction signs. They give direction to special locations like military, international, and fixed-based operator (FBO) sites.

6. Runway Distance Remaining Signs - These are large black signs with a white number that tellpilots the distance remaining during takeoff or landing.

AIRPORT LIGHTINGDuring flight training, you will discover that one of the most challenging, yet fascinating, experi-ences is flying at night. moonlit landscapes and city lights are sometimes breathtaking. From a dis-tance, airports tend to blend into big city lights; however, if you know what to look for, they are easyto spot. Airport lighting is a kaleidoscope of color and each light has both purpose and meaning.since the Federal Aviation Administration controls the airway system, airport lighting is standard-ized.

Who Controls Airport Lighting?Airport lighting is controlled by air traffic controllers at controlled (tower) airports. At uncontrolled(no tower) airports, the lights may be on a timer, or if there is a Flight Service Station (Fss) locatedat an airport, the Fss personnel may control the lighting. A pilot may request various light systemsbe turned on or off and also request a specified intensity. At selected uncontrolled airports, pilots inflight can control the intensity of these runway edge lights from the cockpit. It’s done by using aspecified radio frequency and clicking the microphone. This procedure is called “pilot controlledlighting.”

AIRPORT LIGHTSmost airports have some type of lighting for night operations. The type of lighting systems de-

pends on the volume and complexity of operations at an airport. Airport lighting is standardized sothat airports use the same colors for lights on the runways and taxiways. Below are examples ofsome of the lights at airports:

1. Runway edge lights - Lights used to outline the edges of runways at night or during low visibility

conditions. They are classified according to the intensity they are capable of producing: (1) Low

Intensity Runway Lights (LIRL); (2) medium (MIRL); and (3) High (HIRL). These lights are

white except on instrument runways where amber lights are used on the last half the length of the

runway (or the last 2,000 feet, whichever is less).

32

2. Threshold Lights - Green lights that show the beginning of the runway.

3. End of runway lighting - Red lights that mark the end of the runway you are facing.

4. REIL - Runway End Identifier Lights - High intensity white strobe lights placed on each side of

the runway, especially helpful with reduced visibility, contrasting terrain, and much other lighting.

5. In-Runway Lighting - Touchdown zone lights (TDZL), runway centerline lights (RCLs), and

taxiway turnoff lights are installed on some precision runways to facilitate landing under adverse

visibility conditions. TDZLs are two rows of transverse light bars disposed symmetrically about

the runway centerline in the runway touchdown zone. RCLs consists of flush centerline lights

spaced every 50 feet beginning 75 feet from the landing threshold. Taxiway turnoff lights are flush

lights which emit a steady green color.

6. ALS - Approach Lighting System - If an airport has a precision landing system, there is a good

possibility that it will also have an ALs, or approach lighting system. The ALs is primarily in-

tended to provide a means to transition from instrument flight to visual flight for landing. It de-

pends on whether the runway is designated as “precision” or “nonprecision.” sometimes

beginning as far away as 3,000 feet, some of the more complex systems include sequenced flash-

ing lights which appear to the pilot as a ball of light traveling toward the runway at high speed.

Approach lights can also aid VFR pilots operating under normal conditions.

7. VASI - Visual Approach Slope Indicator - The VAsI lighting system is the most common visual

glide path system and gives pilots a visual indication of the proper approach angle during the land-

ing. The VAsI provides obstruction clearance within 10° of the extended runway centerline, and to 4

nautical miles from the runway threshold. A VAsI consists of light units arranged in bars. There are

2-bar and 3-bar VAsIs. The 2-bar VAsI has near and far light bars and the 3-bar VAsI has near, mid-

dle, and far light bars. Two-bar VAsI installations provide one visual glide path which is normally

set at 3° and the upper glide path one-fourth degree above the lower glide path. The basic principle

of the VAsI is that of color differentiation between red and white. Each light unit projects a beam of

light having a white segment in the upper part of the beam and a red segment in the lower part of the

beam. The lights are arranged so the pilot will see the combination of lights.

White Runway Edge Lights

Basic Runway Lights

A standard two-color VASI

33

8. Tri-Color VASI - This is a system with a single light giving three separate indications. When a pilot

is above the recommended glide path, there will be an amber color displayed. If the pilot is below

the glide path, a red color will be observed. When the pilot makes the necessary corrections and the

airplane is on the recommended glide path, a green colored light will be indicated.

9. Pulse Light Approach Slope Indicator (PLASI) and Precision Approach Path Indicator (PAPI)

- A newer version of a two color visual approach involves a pulsating red light when the pilot is

below and a pulsating white light when the pilot is too high above the recommended path. This is re-

ferred to as the PLASI system. The PAPI lights are usually located on the left side of the runway and

consist of a row of four lights. If the pilot is too high, all four lights will be white. When the recom-

mended glide path is obtained, the left two will be white and the right two will be red. All four lights

will be red if the pilot is too low on the glide path.

10. Taxiway Lights - Blue lights are the norm for taxiway edge lights. However, some airports have

green taxiway centerline lights that may include portions of the ramp. Lights that shine in all di-

rections are called omnidirectional and can be observed at the edge of taxiways.

11. Beacons - These beacon lights guide pilots to airports at night. From a distance, pilots can see

what appears to be flashing colors. If it is a civilian airport, the beacon will flash alternating col-

ors of white and green. If it’s a water airport, the colors will alternately be white and yellow. Hel-

icopter airports, called heliports, have a three color display of green, yellow, and white. military

airports have a distinctive “white-white-green” display.

The newer tri-color VASI

The PLASI system of approach lighting

When an aircraft descends from green to red, the pilot may see a dark amber color during the transition in colors.

34

WIND DIRECTION INDICATORSWind is a key factor in flying, especially in takeoff and

landing. At controlled airports, the tower operators providethis information to pilots in voice and recorded communi-cations. However, when this service is not available, stan-dardized, visual wind indicators become one of the pilot’sbest sources of wind information. These indicators includea wind sock, a wind tee, and a tetrahedron.

Wind socks have been around for decades and they arestill a reliable source of wind direction and speed. Becausethe wind sock is large on one end and small on the other,and can swivel around its pole, it gives the direction and agood indication where the wind is from and how hard it’sblowing. The wind enters the larger end of the sock, in-flates it, and rotates it so that the sock aligns itself to thewind. From the air, a pilot can see this inflated sock and es-timate the speed of the air flow.

Wind tees and tetrahedrons can swing freely, and willalign themselves with the wind direction. The wind tee andtetrahedron can also be set manually by some authority atthe airport. Both the tetrahedron and wind tee point into thewind.

Wind Indicators

At most airports, there isa segmented circle sur-rounding the wind indicator.These can be as simple ashalf-buried car tires that arepainted so they can be seenfrom the air.

Other markings aroundthe segmented circle includetraffic pattern direction indi-cators or landing runway indicators. These markers tell the pilot which way the normal traffic patternflows around an airport. (see associated Activity Three at the end of the chapter.)

Airport Communication

As we have learned, the airport has special lighting, markings, indicators, and signals to ensuresafe take off and landing. The FAA has coordinated these safety features, but has also designatedspecial communication codes between the Air Traffic Controllers and the pilots. A unique alphabetvocabulary is used so that all oral communication at the airport is clear. This phonetic alphabet ispresented in Activity Four at the end of the chapter. Try this associated activity to help you under-stand how aviators clearly communicate to avoid misunderstandings that could cause disasters intake off and landing.

The airport beacon

Wind indicators

windsocktetrahedron

wind tee

35

Activity Three - Look Down; What Are You Seeing? Purpose: Identify parts of an airfield and where each is located from an aerial view.

This is an actual photograph taken of Jefferson County Airport, Broomfield, Colorado. Imaginethat you are flying over this field, or a similar airport, and you are being quizzed by a flight instruc-tor on what you're seeing. Identify as many parts of the airfield as you can. The answers are on thenext page. 1. Taxiway 2. Ramp 3. Runway 29 Right4. Threshold markings 5. Aiming Point 6. side strip

Notice that there is a runway crossing Runway 29R. It is exactly perpendicular, or 90°, to Runway 29R. There is also a runway to the left of runway 29R. It is also at 290°. What would thisrunway be called? The answer is on the next page.

22

Jefferson County Airport, Broomfield, Colorado Courtesy of Raytheon Airport Services

36

Jefferson County Airport, Broomfield, Colorado Courtesy of Raytheon Airport Services

2

3

4

5

6

1

Summary: This activity gives you the opportunity to identify the various parts of an airport. Theanswers for questions 1-6 are labeled on the map below. match the numbers to the names on theprevious page. The runway that is to the left of runway 29R is 29L.

37

Activity Four - Hey You, Bravo-Oscar-Bravo! Purpose: Increase your knowledge of the phonetic alphabet used by pilots and Air Traffic Controllers.

Materials: standard phonic alphabet belowA Alfa “Al-fa”B Bravo “Bra-vo”C Charlie “Char-lee”D Delta “Del-tah”E Echo “Eck-o”F Foxtrot “Fox-trot” G Golf “Golf”H Hotel “Hoh-tell”I India “In-dee-a”J Juliet “Jew-lee-et”K Kilo “Key-lo”L Lima “Lee-ma”m mike “mike”N November “No-vem-ber”O Oscar “Ahs-ker”P Papa “Pah-pa”Q Quebec “Keh-beck”R Romeo “Row-me-o”s sierra “see-air-a”T Tango “Tang-go”U Uniform “Yew-nee-form”V Victor “Vic-tah”W Whiskey “Wiss-key”X X-Ray “Ecks-ray”Y Yankee “Yang-key”Z Zulu “Zoo-loo”

Procedure: You've probably heard someone try to spell out a word using other words like “...that's N,

as in Nancy,” or “B...like boy.” In the world of aviation, there is an organization called the ICAO, or

International Civil Aviation Organization, and they have established English as the world-wide lan-

guage of aviation. Along with this, they have selected 26 words which help in transmitting clear com-

munications. This is known as the phonetic alphabet.

Have each participant stand and give his/her name in phonetic alphabet. It's quick, it's fun, and it's a

learning experience. But, first try these just for grins!

1. Who am I? Juliet, Oscar, sierra, Hotel, Uniform, Alfa

2. Who am I? Tango, Uniform, Romeo, Kilo, Echo, Yankee

3. Who am I? sierra, Papa, Alfa, Charlie, Echo, Charlie, Alfa, sierra, Echo?

Summary: This activity helps to familiarize you with the phonic alphabet which many people outsidethe aviation field use to clearly communicate orally. Hopefully this will be helpful to you in the future.

38

Learning Outcomes

- Describe the basic layout of a

sectional chart.

- Explain the sectional chart

legend.

- Identify latitude and longitude lines.

- Identify features such as railroads, pipelines, obstructions, and highways.

- Identify all of the information given about an airport.

Important Terms

cartography - the art and science of creating charts and mapschart - a projection, usually on paper, showing a body of land and other features, such as water, that

gives information, usually in the form of symbols, graphs, or illustrationslatitude - a system of lines that run parallel to the equator, also known as parallelslegend - an illustration showing the symbols that are used on chartslongitude - a system of lines, known as meridians, between the north and south polesmap - a representation of the surface of the Earth (or of the sky/space above)nautical mile - a unit of length that is approximately 6076 feetprojection - a method of transferring a portion of the Earth’s surface onto a flat chart; the most

widely used in aeronautical charts being the Lambert Conformal Conic Projectionrelief - a term used to describe elevations, which is depicted by color tints, contour lines, and

shading on mapssectional - a chart specifically designed for aviation use and Visual Flight Rules, with the scale being

1:500,000 or approximately 8 statute miles to one inchscale - the size of an item, or area, on a chart, compared to it in actualitystatute mile - a unit of length that is 5,280 feettick - a small, or abbreviated mark on a lineWAC - The World Aeronautical Chart, which covers a much larger area than the sectional chart; the

scale of the WAC being 1:1,000,000 or approximately 16 statute miles per one inch

33An excerpt from an aeronautical sectional chart

A SYSTEM OF GLOBAL ORGANIZATION

The most commonly used aeronautical“map” is known as the Sectional Chart. It hasa scale of 1 inch to 500,000 inches, or approxi-mately 8 statute miles. The nautical mile

equivalent is approximately 6.85 miles. Thesecharts are based on the principle of a Lambert

Conformal Conic Projection and locations arepositioned according to lines of latitude andlongitude. The World Aeronautical Chart iseven larger than the sectional chart, but in thischapter we will focus on the sectional chart.

The lines of latitude are shown with a straight arrow. ———

The lines of longitude are shown with curved arrows. ———

The small arrows show the "ticks" that represent minutes. ——

Lines of longitude (meridians) and latitude (parallels)

39

40

SECTIONAL AERONAUTICAL CHARTSThe sectional Aeronautical

Charts are shown in this illus-tration. The cartography

used to create these charts isrevised every 6 months, butthere are a few located outsideof the 48 contiguous statesthat are revised annually. Thescale of this chart is1:500,000 and it is based onthe Lambert Conformal ConicProjection.

In the illustration, you willsee the chart title and thatrefers to a primary city withinthe coverage of the sectional.Note the one we are using isWichita, a large city located inthe state of Kansas. Others,like Las Vegas, Chicago,miami, Dallas-Ft.Worth,Phoenix, and Houston, allhave small blotches withintheir area. This means thatthere is additional informationavailable for their large air-ports in the form of TerminalArea Charts.

The black arrows in theupper right and left cornersindicate which side of thesectional is north and whichis south. There is a band ofcolor (vertical) just below theillustration of the Unitedstates. This graphic showsthe gradient tints assigned toeach one thousand feet of el-evation, called relief. Colorsrange from a green at sealevel to a golden tint, at highareas. The “8720” is the max-imum height that is repre-sented on the Wichitasectional. This is an actual, full-size face panel of a Sectional Aeronautical Chart

for Wichita, Kansas and surrounding territories.

41

THE LEGEND AND ITS SYMBOLSThe sectional chart not only dis-

plays airports, it has cities, towns,railways, rivers, radio navigationaids, power lines, obstructions, andother landmarks that pilots can useas visual checkpoints along a routeof flight. All of these features aredepicted in various colors andforms. To learn how they are repre-sented, you must become familiarwith the chart’s legend. This is acolorful array of symbols andgraphics that represent features ofinterest to pilots.

Using the legend shown here, tryto locate the following symbols onthe Wichita sectional excerpt shownon page 42. This activity will giveyou a challenge that will help pro-mote a better understanding of thelegend. Work with a partner to as-sist each other in locating eachsymbol.

• Obstruction below 1000 ft. AGL• mines and quarries • small town shown in yellow• Private-non public use airport• Power transmission line• Interstate Highway 80• Nondirectional radio beacon• Railroad track • Visual check point• Parachute jumping area• Class C airspace• Group obstruction• Outdoor theater• small river• Wichita VORTAC • A longitude line• A latitude line• Golf course• sand pit• Race track

The legend for the Wichita Sectional Aeronautical Chart

42

This is an excerpt from the Wichita sectional and it covers an area in northern Oklahoma.

The Kansas border is 37° Latitude and just west of Enid is 98° Longitude.

43

AirportsYou will notice that

the legend has “blocks”of information. Usingthe two airport blocks,notice how a symbol re-lates to an actual symbolon the excerpt. Oftentimes, the legend sym-bol doesn’t exactly fitthe one in the block.That’s when you have tolook around for other re-lated graphics. Here’s anexample: Go to blockmarked Airports that hasbeen superimposedupon the exerpt. Thesecond line down is ablue symbol with an “x”in it. This is the symbolfor a tower-controlledairport with a hard-sur-faced runway between1500’ and 8069’ long.There is a black line thatconnects that symbol tothe one on the chart.This is Enid WoodringAirport. Its longest run-way is 6400 feet and itfalls between the 1500-8069 limits. The runwayis hard-surfaced. Noticethat there is a small staron top of the Enid-Woodring symbol andtabs sticking out. Goback to the block of in-formation and you’ll seea little blue star at thebottom. It says, “* Ro-tating airport beacon inoperation sunset to sun-rise.” Enid-WoodringField has a beacon and itis shown on the symbol.

Wichita sectional

44

�

Now look down at the lower portion of the box and you will see symbols, although the wrong color,that have tabs. The information says, “services: fuel available and field tended during normal work-ing hours depicted by use of ticks around basic airport symbol.” They call them ticks, but they looklike tabs.

In order to get the meaning of the symbols used,you have to do a little digging. If you carefully exam-ine the Enid-Woodring Airport symbol, you will noticea small dot in about the 5 o’clock position. To solve themystery of the dot, it’s buried in the AIRPORTs blockof information. Can you find it?

Looking back at the Airport Data block on the ex-erpt on page 43, you will see a black line going fromthe text to the magenta information around “Chero-kee.” Note that the information in the AIRPORTDATA is blue and the information around Cherokee’sairport is purple. Now, look back at the informationaround Enid-Woodring Airport. It is blue. Woodring has a control tower and Cherokee does not. It issaid to be uncontrolled. Note also that the Cherokee airport symbol has a tiny star on top of it. Thismeans that it has a rotating beacon operating from sunset to sunrise.

Let’s take a look at the airport data and see what it’s all about. Of course, CHEROKEE is thename of the airport and the name of the town. Notice right after the name CHEROKEE, there is (OK6). If you will look back up into the data block, you will see (NAm) and a small arrow pointing to itwith “Location Identifier” written. This means that Cherokee airport is identified with that symbol. Ifit were Los Angeles International Airport, it would be LAX, Dallas-Ft. Worth would be DFW, seat-tle, sEA, etc.

Remember-Uncontrolled Airports Are Magenta, Controlled Airports Are Blue

Under the first line of information about Cherokee is “1177 L 38 122.9 .” Again, looking back atthe information block, you will see that the 1177 relates to the “elevation in feet.” so Cherokee hasan elevation above sea level of 1,177 feet. The L is “Lighting in operation sunset to sunrise.” The 38is the “Length of the longest runway in hundreds of feet.” Cherokee has a runway that is 3800 feetlong. Now, look at the Cherokee airport symbol. It is magenta and there is a line in the middle of it.If you go back down to the AIRPORTs block, you will see the second symbol, again shown in ma-genta, and this says it is a hard-surfaced runway between 1500’ to 8069’ in length. Cherokee has ahard-surfaced runway that is 3800’ long. You can see that information is often buried in anotherblock and you have to hunt for it.

Once You’ve Mastered Cherokee, Try All of the Airports on the Sectional!

The next information in the Cherokee airport data is the 122.9. This is the UNICOm and it isidentified in the AIRPORT DATA block with a small arrow. Down in the lower portion of the AIR-PORT DATA block, you will see a definition for UNICOm. It is an "Aeronautical advisory station"and not a control tower. It means that the airport has an advisory on items such as wind direction,

services available, and traffic pattern directions. The c at the end of the information means this is a“Common Traffic Advisory Frequency.”

The Cherokee, Oklahoma Airport

symbols and information

Airports- Time to Visit One!Now that you have learned a good deal

about airports, it is time to go and visit one.You can arrange a visit through an adult withwhom you are working on this module. Ifyou are lucky, you will be able to take anorientation flight to see the airport from theair, hear the communications of the Air Traf-fic Controllers, and observe the final ap-proach for landing. Blue skies to you! (seeassociated Activity Five at the end of thechapter.)

45

This is what is seen when you fly in an airplane. Once the

runway is lined up, full power is added for take-off. It is

one of the most exciting moments of flight.

46

Activity Five - The Final Approach!!Purpose: simulate the final approach and landing of an airplane.

Materials: a plastic toy airplane with fixed landing gear, two eye screws, 30-40 feet of fishing line,

a stick or broom handle 18-24 inches long, masking tape, and two people. Note: The model airplanes

can be purchased in most variety stores. The nylon fishing line and eye screws can be found at any

hardware store, or large center, like Wal-mart.

Procedure:

1. Put the two eye screws in the back of the toy airplane so that it hangs straight and level on the

fishing line.

2. Tie one end of the fishing line up high in a room.

3. Thread the fishing line through the eye screws on the back of the plane.

4. Tie the other end of the fishing line to the stick, which becomes the pilot's “joystick.”

5. Lay out the runway on the floor with masking tape. Place the joystick at the far end of the runway.

6. One person takes the airplane to the top of the line and releases it while the pilot, seated just be-

yond the runway, moves the joystick forward and backwards to adjust the speed in order to land

on the runway.

If the pilot pulls back too tightly on the stick, the plane will overshoot the runway. Pushing forward

increases the speed of the plane coming down the fishing line. The object is to land the plane inside the

runway limits. Prac-

tice makes perfect

on this activity!

Summary: This is

a great activity for

simulating a land-

ing and the diffi-

culty involved in

judging both speed

and angle upon

final approach, de-

scent, and landing.

22

47

Too tight a line willcause overshoot.

Control or Joystick

Looser linewill bring it in.

Upper End of Line

(pedrson to

release plane)

(person to

control joystick)

48

3

Aerospace Dimensions

AIR ENVIRONMENT

3

Aerospace Dimensions

AIR ENVIRONMENT

MODULE

Civil Air PatrolMaxwell Air Force Base, Alabama

3

Aerospace Dimensions

AIR ENVIRONMENT

3

Aerospace Dimensions

AIR ENVIRONMENT

WRITTEN BY

DR. JEFF MONTGOMERY

DR. BEN MIllspauGh

DEsIGN

BaRB pRIBulICK

IllusTRaTIONs

pEGGY GREENlEE

EDITING

BOB BROOKs

susaN MallETT

NaTIONal aCaDEMIC sTaNDaRD alIGNMENT

JuDY sTONE

puBlIshED BY

NaTIONal hEaDQuaRTERs

CIVIl aIR paTROl

aEROspaCE EDuCaTION DEpuTY DIRECTORaTE

MaXWEll aFB, alaBaMa 36112

ThIRD EDITION

JuNE 2013

INTRODUCTION

ii

The Aerospace Dimensions module, Air Environment, is the third of six modules, which com-bined, make up Phases I and II of Civil Air Patrol's Aerospace Education Program for cadets. Eachmodule is meant to stand entirely on its own, so that each can be taught in any order. This enablesnew cadets coming into the program to study the same module, at the same time, with the othercadets. This builds a cohesiveness and cooperation among the cadets and encourages active groupparticipation. This module is also appropriate for middle school students and can be used by teachersto supplement sTEm-related subjects.

Inquiry-based activities were included to enhance the text and provide concept applicability. Theactivities were designed as group activities, but can be done individually, if desired. The activitiesfor this module are located at the end of each chapter, except chapter one.

CONTENTS

iii

Introduction .............................................................................................ii

Contents...................................................................................................iii

National Academic Standard Alignment ..............................................iv

Chapter 1. The Atmosphere ....................................................................1

Chapter 2. Air Circulation ......................................................................4

Chapter 3. Weather Elements ...............................................................11

Chapter 4. Moisture and Clouds ..........................................................19

Chapter 5. Weather Systems and Severe Weather..............................32

A F-22 Raptor climbs above the great Alaskan mountain range (USAF photo)

iv

National Academic Standard Alignment

Learning Outcomes

- Describe the composition of the atmosphere.

- Describe the standard temperature lapse rate.

- Identify the four layers of the atmosphere.

Important Terms

ionosphere - a region of the atmosphere where electrons are gained or lost

lapse rate - the rate of decrease with an increase in height for pressure and temperature

mesosphere - a layer of the atmosphere extending from about 30 to 50 miles

ozonosphere - a region of the atmosphere where ozone is created

stratosphere - a layer of the atmosphere extending from the tropopause to about 30 miles

thermosphere - a layer of the atmosphere extending from 50 to about 300 miles

tropopause - boundary between the troposphere and the stratosphere

troposphere - first layer of the atmosphere where most of the Earth’s weather occurs

The atmosphere is a blanket of air made up of a mixture of gases that surrounds the Earth andreaches almost 350 miles from the surface of the Earth. This mixture is in constant motion. If the at-mosphere were visible, it might look like an ocean with swirls and eddies, rising and falling air, andwaves that travel for great distances.

Life on Earth is supported by the atmosphere, solar energy, and the planet’s magnetic fields. Theatmosphere absorbs energy from the sun, recycles water and other chemicals, and works with theelectrical and magnetic forces to provide a moderate climate. The atmosphere also protects life onEarth from high energy radiation and the frigid vacuum of space.

COMPOSITION OF THE ATMOSPHEREIn any given volume of air, nitrogen accounts for 78 percent

of the gases that comprise the atmosphere, while oxygen makesup 21 percent. Argon, carbon dioxide, and traces of other gasesmake up the remaining one percent. A variable amount of watervapor can also be present, and this amount can be responsible formajor changes in our weather.

1

11

Apollo 17 view of Earth

ATMOSPHERIC LAYERSCertain levels of the atmosphere can be identified according to general characteristics, such as

temperature distribution and physical and chemical properties. There are four distinct regions or lay-ers of the atmosphere where the temperature distribution is different enough to justify a differentname.

The first layer, known as the troposphere, extends from sea level up to 20,000 feet over the polesand to 55,000-60,000 feet over the equatorial regions. most of the atmosphere is contained in this re-gion, and the vast majority of weather, clouds, storms, and temperature differences occur here. Tem-peratures within the troposphere decrease with an increase in altitude at a fairly constant rate. Thistemperature decrease is generally accepted to be at a rate of about 3.5˚F or 2˚C for every 1,000 feetof altitude gain. This is called the standard lapse rate for temperature.

At the top of the troposphere is a boundary known as the tropopause, which is the dividing areabetween the troposphere and the next layer. The altitude of the tropopause varies with latitude andwith the season of the year.

The next region of the atmosphere is the stratosphere, which extends from the tropopause to aheight of about 160,000 feet or about 30 miles. Little weather exists in this layer and the air remainsstable although certain types of clouds occasionally exist in it. The temperature actually gets warmerwith an increase in altitude; usually moving from a temperature of -76° F to about -40° F. The U-2aircraft pictured on the next page is an example of a airplane that routinely flies in the stratosphere.

The next atmospheric region is the mesosphere. The mesosphere extends from beyond the strato-sphere to about 280,000 feet or from about 30 to 50 miles. At first, the temperature increases in themesosphere, but then it decreases at the top of the layer to about -130° F. Finally, the last regionidentified by temperature differences is the thermosphere. It begins at about 50 miles up and ex-tends to about 300 miles. Here, the temperature increases again. How much it increases depends onsolar activity, but it is usually between 1,380° F and 2,280° F.

2

The four layers of the atmosphere

There are two atmos-pheric regions that can bedescribed by the physicaland chemical processes thatoccur within them. First,there is the ozonosphere. Itextends from about 10 to 30miles in altitude. In this re-gion, the sun’s radiation re-acts with the oxygenmolecules and causes themto pick up a third atom, cre-ating ozone. The ozonos-phere performs the veryimportant function of shield-ing us from ultraviolet andinfrared radiation.

The next region describedby these physical and chemi-cal processes is the ionosphere. This region begins at an altitude of about 25 miles and extends out-ward to about 250 miles. Because of the interactions between atmospheric particles and the sun’sradiation, there is a loss or gain in the electrons of the atoms and molecules, and thus the word “ion.”

3

ONE OF THE MOST FAMOUS SPY PLANES OF ALL TIME, THE LOCKHEED U-2

This airplane routinely flies at extremely high altitudes

into both the tropopause and stratosphere layers.

The majesty of our atmosphere with the Moon barely visible in the distance

Images courtesy of NOAA

4

22Learning Outcomes

- Describe how the sun heats the Earth.- Describe the Earth's rotation and revolution, and its effect on the Earth's seasons.- Explain the various theories of circulation.- Describe Coriolis Effect (Force).- Define the jet stream.

Important Terms

autumnal (fall) equinox - the time when the sun's direct rays strike the equator resulting in day andnight of equal length, usually on september 22nd or 23rd

Coriolis Effect (Force) - is the apparent deflection of a freely-moving object to the right in theNorthern Hemisphere

doldrums - a global area of calm winds

global winds - the world-wide system of winds that transfers heat between tropical and polar regions

jet stream - a strong wind that develops at 30,000-35,000 feet and moves as a winding road acrossthe Us, generally from the west to the east

polar easterlies - global winds that flow from the poles and move to the west

prevailing westerlies - global winds that move toward the poles and appear to curve to the east

radiation - the method by which the sun heats the Earth

revolution - the movement of the Earth revolving around the sun; full revolution about 365 days

rotation - how the Earth turns (rotates) on its axis at an angle of 23.5° while it revolves around thesun; full rotation 24 hours

summer solstice - the longest day when the sun isat its northernmost point from the equator in theNorthern Hemisphere, usually on June 21st or22nd

trade winds - a warm steady wind that blows to-ward the equator

vernal (spring) equinox - the time when the sun'sdirect rays strike the equator resulting in day andnight of equal length, usually on march 21st or22nd

winter solstice - the shortest day when the sun isthe farthest south of the equator and the NorthernHemisphere, usually on December 21st or 22nd

This world map is divided into horizontal (lati-

tude) lines in degrees of a point north or south of

the equator, often called parallels. The vertical

(longitude) lines, often called meridians, point

east or west of the Prime (Greenwich) Meridian.

5

The sun heats the Earth. This is the funda-

mental cause of our various weather condi-

tions. However, the sun heats some parts of the

Earth more than others. This uneven or unequal

heating causes temperature and pressure differ-

ences. This creates circulation or movement of

air. This movement initiates the whole weather

process.

The activities in this section are designed to

give you a better understanding of uneven heat-

ing and the circulation it creates.

RADIATIONThe sun heats the Earth through a method

known as radiation. The energy from the sun ra-

diates into the Earth's atmosphere. As already

mentioned, the sun heats the Earth unevenly. This

heat from the sun is absorbed differently depend-

ing on the surface or the substance. For example,

if you go to the beach on a hot day and take your

shoes off and walk in the sand, the sand will be

almost too hot to walk on, but the water will be

cool. Go back at 11:00 at night. The sand will be

cool while the water will be comfortably warm.

The sand absorbed and lost heat faster than the

water. About 50% of the sun's radiation is ab-

sorbed by the Earth's surface. The other 50% is

reflected and absorbed in the atmosphere and

space. (see associated Activity One at the end of the chapter.)

Warm air rises and this impacts weather in a big way. This rising warm air adds to temperature

and pressure differences, as well as air movement. This effects the surrounding air, air masses, and

fronts. It is also an ingredient for producing clouds and plays a part in the occurrence of moisture

and precipitation. (see associated Activity Two at the end of the chapter.)

Aircraft are affected by warm air, too. Air is made up of molecules and warm air has less mole-

cules than cool air. The warm air molecules are spaced farther apart, so the air is less dense or thin-

ner. so, airplane engines work more efficiently in dense, colder weather.

ROTATION AND REVOLUTIONIn relationship to the sun, the Earth has two motions that affect the amount of heat received from

the sun. These motions are rotation and revolution. The Earth revolves around the sun, and at the

same time, rotates as well. The Earth's revolution takes 365 days, 5 hours and 48 minutes, while the

Earth is rotating on it axis at an angle of 23.5 degrees. This rotational tilt causes the length of the

days to vary and the rotation plus the revolution causes the seasonal changes. As demonstrated on

The flight of aircraft is affected by heat and cold.

Solar Radiation

6

EquinoxMarch 21-22Sun vertical at equator

EquinoxSeptember 22-23Sun vertical at equator

SUN

23 1/2

SolsticeDecember 21-22Sun vertical Latitude 23 1/2 S

SolsticeJune 21-22Sun vertical Latitude 23 1/2 N

Seasonal changes caused by the Earth's rotation and revolution

next page, the Earth's axis stays tilted in the same direction as it revolves around the sun. The dia-

gram shows that the Northern Hemisphere is tilted toward the sun on June 21st or 22nd. This is

called the summer solstice. This day marks the longest day of the year in the Northern Hemisphere

when the sun is at its northernmost point from the equator. December

21st or 22nd is the date when the Northern Hemisphere is tilted away

from the sun and the sun is the farthest south of the equator. This is

called the winter solstice. During the spring (vernal) equinox, which

occurs on march 21st or 22nd, and the fall ( autumnal) equinox, which

occurs on september 22nd or 23rd, the sun's rays cross the equator. so,

days and nights are of equal length. (See the diagram at the top of page.)

Our Earth rotates on its axis in a counterclockwise direction. The

winds associated with the rotation cause an object moving freely in the

Northern Hemisphere to be appear to be deflected to the right of its in-

tended path. This deflection to the right is called Coriolis Effect (Force). As the drawing indicates,

an airplane flying south from the North Pole to the equator must take the Coriolis Effect (Force) into

account. If it doesn't, it will land west of its intended destination. (see associated Activity Three at

the end of the chapter.)

CIRCULATION AND GLOBAL WINDSUnequal heating causes air movement. Globally, this movement is called circulation or the gen-

eral circulation of the atmosphere. This general circulation may be regarded as the world-wide sys-

tem of winds that transfers heat between tropical and polar regions called global winds.

The region of the Earth receiving most of the sun's heat is the equator. Here, air is heated and

The Coriolis effect (Force)

7

rises, leaving low pressure areas

behind. moving to about 30°

north and south of the equator, the

warm air from the equator finally

begins to cool and sink. Between

30° latitude and the equator, most

of the cooling, sinking air moves

back to the equator. The rest of the

air flows toward the poles. The air

movements toward the equator are

called trade winds - warm, steady

breezes that blow almost continu-

ously. The Coriolis Effect (Force)

makes the trade winds appear to

be curving to the west, when they

are actually traveling toward the

equator from the south and the

north.

The trade winds coming from

the south and the north meet near

the equator. These converging trade winds produce general upward winds as they are heated, so there

are no steady surface winds. This area of calm is called the doldrums.

Between 30° and 60° latitude, the winds that move toward the poles appear to curve to the east.

Because winds are named for the direction from which they originate, these winds are called pre-

vailing westerlies. Prevailing westerlies in the Northern Hemisphere are responsible for many of the

weather movements across the Us and Canada.

At about 60° latitude in both hemispheres, the prevailing westerlies join with polar easterlies to

produce upward motion. The polar easterlies are formed when the atmosphere over the poles cools.

This cold air then sinks and spreads out over the surface. As the air flows away from the poles it is

turned to the west by the Coriolis Effect (Force). Again, because these winds begin in the east, they

are called the easterlies. many of the changes in wind direction are hard to visualize, but hopefully

the diagram above will help.

These global winds are a constant concern for pilots. Pilots receive a weather briefing before

takeoff. During the briefing, the direction and speed of the winds between their takeoff point and

their destination are always examined at various levels

of altitude. (see associated Activity Four at the end of

the chapter.)

JET STREAMAnother interesting concept is the jet stream.The jet stream usually crosses the Us at 30,000-

35,000 feet, generally moving in a west to east direction.The jet stream develops when there are strong tempera-ture differences in the upper troposphere. These large

Polar Front

Polar Easterlies

PrevailingWesterlies

Polar Easterlies

Prevailing Westerlies

NortheastTrade Winds

SourtheastTrade Winds

60O

30O

0O

30O

Global winds

Jet stream

temperature differences cause large pressuredifferences, which create stronger winds.

The jet stream's winds are generally be-tween 100-300 miles per hour (mph), with anaverage of 120-150 mph. However, speedshave been recorded as high as 450 mph. Thejet stream moves like a winding road acrossthe Us It is generally thousands of mileslong, hundreds of miles wide, and a fewmiles deep. It is usually stronger and dips far-ther south in the winter.

Both commercial and military pilots arewell aware of the location of the jet stream.In fact, many flight plans are filed with thejet stream in mind. Why is that? since the jetstream moves west to east, a plane flying eastcan save time and fuel by riding the jetstream to the plane's destination. Passengersare usually very happy about arriving 30-60minutes early. Of course, the opposite is alsotrue. Planes flying west may be flying intothe jet stream. This will slow them down, orthey can try to avoid the jet stream.

8

The jet stream affecting the United States moves up and

down across the continent. When it is farther north, as in

Canada, the weather to its south tends to be mild, or, at

least, less cold. When the jet stream swings south into the

United States, especially in winter, very cold, often harsh

weather prevails at the surface on the northern side.

This diagram shows

two typical jet

stream positions at

the height of sum-

mer and of winter.

9

Activity One - Absorbing Heat

Purpose: Compare and contrast the absorption of heat by soil and water to better understand how thisaffects weather.

Materials: 2 tin cans, 2 thermometers, soil, water, sunlight, pencil, and paper

Procedure:

1. Fill one can with water and the other can with soil.2. stand one thermometer in the water and insert the other into the soil.3. Read the thermometers, and record temperature and time of each.4. Place both cans into the sunlight.5. Watch the readings on the thermometers, and record temperature and time of each.6. Notice the temperature of the soil begins to rise first. 7. Discuss the implications this temperature variance has on weather.

Summary: The temperature of the soil begins to rise first. This is because the soil absorbs heat fasterthan the water. If placed in the shade, the soil will lose heat faster than the water. The unequal heating ofthe Earth causes differences in temperature and pressure.

Activity Two - Warm Air Rising

Purpose: Use observation skills to learn that warm airrises to better understand weather conditions caused bythis upward air movement.

Materials: paper, pencil with eraser, scissors, metalthimble, needle, sewing thread spool, and table lamp

Procedure:

1. mark the pattern of a spiral on the paper, with turnsabout an inch wide.

2. Cut the pattern from the paper, leaving enough spacein the center to partially insert the thimble.

3. make a hole in the center for the thimble, and pressthe bottom of the thimble half way through the hole.

4. Remove the threaded nut from the top of the lampshade and place the spool over the threaded stud.

5. Insert the needle in the top of the eraser of the pencil,and place the other end of the pencil in the spool hole.

6. Carefully set the thimble and paper spiral over thepoint of the needle. The point of the needle makes

22WATER

SOIL

10

Activity Three - Coriolis Effect (Force)

Purpose: The purpose of this activity is to demonstrate the path of Coriolis Effect (Force).

Materials: a globe and chalk

Procedure:1. Place one hand on top of the globe and slowly turn it in the same

direction that the Earth spins (to the right in a counterclockwise direction).2. As the globe turns, draw a chalk line directly down from the North Pole toward

the south Pole.3. stop the globe and examine the chalk line. It will not be a straight line but a curved line that crosses the

equator at an angle. The chalk line will look like it was drawn from the northeast toward the southwest.4. Discuss with the group how the Coriolis Effect (Force) works and its effects on airplanes flying through it.

Summary: This activity demonstrates Coriolis Effect (Force), which occurs from the wind effects associ-ated with the rotation of the Earth. Coriolis Effect (Force) deflects a freely moving object to the right inthe Northern Hemisphere and to the left in the southern Hemisphere. It is important to realize that pilotsplan for this when they are flying to avoid being deflected off their planned flight course.

RR oo tt aa tt ii oo nn

RR oo tt aa tt ii oonn

Equator

very little contact with the thimble, and, thus, makes a verygood pivot point with little friction.

7. Turn on the lamp, observe the movement of the spiral and dis-cuss why the spiral begins to turn.

Summary: The lamp heats the air and the molecules of air ex-pand, making the air less dense, and, thus, lighter. Cooler, heavier air moves in and pushes the warm airup. The warm air pushes on the spiral, and it begins to turn. This same warm rising air affects the weather.It can lead to cloud formations, which can lead to precipitation and storms. Thus, pilots have to constantlymaintain awareness of weather conditions caused by the upward movement of warm air molecules.

Safety Precautions1. Be careful with the scissors when

cutting the paper.2. Be careful when handling the needle.3. Light bulbs get hot very fast, so be

careful when lamp is on.

Activity Four - Wind CurrentsPurpose: Conduct a visual demonstration of windcurrents as air moves up and over mountains.

Materials: electric fan, stack of different sizedbooks, and a strip of tissue paper

Procedure:

1. stack the books to form a small mountain.2. Place the fan a few feet from the books so a strong breeze blows over the stack.3. Hold one end of the tissue paper over the books so that it blows.4. Observe the motion of the tissue paper as the wind from the fan blows it. 5. Discuss what is happening and why.

Summary: The tissue on the side of the books nearest the fan rises up, while the tissue on the sideaway from the fan descends. mountain ranges can alter the temperature, pressure, and direction ofthe prevailing winds. Near the coast, mountains may even block ocean breezes from inland areas.These wind currents can affect flight. Thus, pilots remain constantly aware of such changes in the at-mosphere to ensure optimum performance of the airplane.

11

Learning Outcomes- Define wind.- Describe the Beaufort scale.- Define heat.- Explain what temperature is and how it can be expressed on scales.- Describe what wind chill is and what it does.- Describe how a microburst can affect a plane’s flight.

Important Terms advection - lateral transfer of heatatmospheric pressure - the weight of all of the atmosphere's gases and molecules on the Earth's

surfaceBeaufort Scale - a scale for estimating wind speed on land or seaconduction - heating by direct contactconvection - heat transfer by vertical motionheat - the total energy of all molecules within a substancemicroburst - a downdraft or down burst phenomenon that creates unstable air and thunderstorm turbulenceradiation - heat transferred by the suntemperature - a measure of molecular motion expressed on a man-made scalewind - a body of air in motion wind chill - temperature and wind speed used to explain how cold it feels

WINDThis chapter discusses three of the very basic weather elements: wind, temperature, and pressure.

These elements will be defined and you can conduct activities which will give you a better under-standing of how these elements contribute to the overall weather.

Let's begin with a brief discussion of wind. Wind is a body of air in motion. It is described as hav-ing direction and speed. Wind direction is defined as the direction from which the wind is blowing.For instance, if the wind is blowing from the west, it is called a west wind. A wind blowing from thenorthwest is called a northwest wind. Here in the Us, wind speed is expressed in either miles per houror knots. A knot is a common nauticaland aviation term. One knot equals 1.15miles per hour and one knot is equiva-lent to one nautical mile per hour, whichis 6,076’.

The illustration to the right demon-strates an easy way to estimate wind-speed. It isn’t precise, but it can give agood estimate. (see associated ActivityFive at the end of the chapter.)

33

calm 10 mph 20 mph 30 mph

12

There is another tool for estimating wind speed. This one works on land or sea. It is called theBeaufort Scale and has been around since 1805. It is still widely used today. On a windy day, takethe Beaufort scale (below) outside and estimate the wind speed. Do this a few times during the dayand then compare your estimations with the local weather report that night.

Wind is an interesting phenomenon all by itself. However, if you apply temperature into the situa-

tion it gets even more interesting, especially cold temperatures. We have all heard of the wind chill,

but what exactly is it and how does it work? To determine wind chill, temperature and wind speed

are used to explain how cold it feels. It may be 30° F outside, but feels like 9° F because of the com-

bination of cold temperature and strong winds. Actually, heat is escaping from your body and warms

the air next to you. If the wind is calm or almost calm, the warm air will stay next to your body.

However, if the wind is blowing, it blows the warm air away from your body, and the faster it is

blowing, the faster the heat is being carried away causing you to feel colder. Thus, the pysiological

effect of wind chill on the body is important to maintain safe body temperature. The wind chill index,

noted on next page, can help to calculate wind chill. The actual formula used to determine wind chill

Beaufort Number

0 under 1 calm sea like a mirror calm; smoke rises vertically

1 1-3 lightair

ripples with appearance offish scales; no foam crests smoke drift indicates wind

direction; vanes do not move

2 4-7 light breeze

small wavelets; crests of glassy appearance; not breaking

wind felt on face; leavesrustle; vanes begin to move

3 8-12 gentle breeze large wavelets; crests begin to

break; scattered whitecaps leaves, small twigs in constant motion; light flags extended

4 13-18 moderate breeze

small waves, becoming longer;numerous whitecaps dust, leaves, and loose paper

raised up; small branches move

5 19-24 fresh breeze

moderate waves, becoming longer; many whitecaps; some spray small trees begin to sway

6 25-31 strong breeze

larger waves forming; whitecaps everywhere; more spray large branches of trees in motion;

whistling heard in wires

7 32-38 moderate gale

sea heaps up; white foam frombreaking waves begins to blow streaks whole trees in motion; resistance felt

in walking against wind

8 39-46 fresh gale

moderately high waves of greater length; foam is blown in well-marked streaks twigs and small branches

broken off trees

9 47-54 strong gale

high waves, sea begins to roll; dense streaks of foam; spray may reduce

visibilityslight structural damage occurs; slate

blown from roofs

10 55-63 whole gale

very high waves with overhanging crests; sea takes white appearance;

visibility reducedseldom experienced on land; trees broken;

structural damage occurs

11 64-72 storm exceptionally high waves; sea covered with white foam patches very rarely experienced on land;

usually with widespread damage

12 73 or higher

hurricaneforce air filled with foam; sea completely

white with driving spray; visibility greatly reduced

violence and destruction

Wind Speed(mph)

Seaman'sTerm

Effects at Sea Effects on Land

Beaufort Scale

13

has various variables, and is different in many countries. If you want to find out more about the ac-

tual formulas used, go to the National Weather service Website at http://www.weather.gov/os/wind-

chill/index.shtml.

How does wind affect flying? Wind speed and wind direction always impact flying. The smallerplanes are affected more than the larger planes. Airplanes takeoff into the wind because the windgives the plane more lift. This allows the plane to leave the ground faster. The wind direction is im-portant because if crosswinds get too high, planes can't takeoff or land safely. Crosswinds are windsblowing toward the side of the plane. strong crosswinds can blow planes off course. Base operationsor the control tower will not allow planes to takeoff or land if the winds are unsafe. A plane's windcapability has already been determined by the manufacturer and is published in the plane's manual.

While planes are en route to their destinations, winds are very important. Pilots love having a tail-wind. This is a wind that is blowing from the same direction the plane is flying. Tailwinds will re-duce the overall flying time and allow the plane to arrive at its destination earlier. On longer flights,

tailwinds can save pilots a significantamount of time and fuel. (see associatedActivity six at the end of the chapter.)

There is another weather phenomenoninvolving winds that impacts flying in avery crucial way. That phenomenon is amicroburst. For many years, authoritieshave realized that microbursts have beenresponsible for several aircraft accidents.microbursts are particularly dangerousduring takeoffs and landings.

A microburst is defined as a down-draft or downburst. It is a column ofsinking air that as it nears the ground orhits the ground diverges in many direc-tions. These winds associated with a mi-croburst can reach 100 - 150 miles perhour and cause considerable damage.Because these diverging winds happen at

or near ground level airplanes are so much more vulnerable during takeoffs and landings. A mi-croburst can occur very suddenly leaving little time to react to these diverging winds. microburstshave a diameter of 2.5 miles or less and can be associated with or without precipitation.

When a microburst happens at normal flying altitudes there may be bumps and bruises, but theplane will recover. When it happens near the Earth’s surface, there may not be time to recover. Fly-ing near thunderstorms is dangerous, but when a microburst is involved, it is extremely dangerous.

An example of a microburst

How to find wind chill: Wind Chill Index

Temperature in FoW

ind

Spee

d0 mph 30o

9o

4o

1o

-2o

-3o

-7o

-10o

-10o

-15o

-18o

-17o

-22o

-25o

-24o

-29o

-33o

-31o

-36o

-41o

-39o

-44o

-49o

2o -5o -11o -18o -25o -31o

25o 5o 0o20o 15o 10o

15 mph

20 mph

25 mph

30 mph Example: 20 mph wind, 10o F =wind chill of -24o F

Ph

oto

cre

dit W

ikip

ed

ia

14

TEMPERATUREWe know that uneven heating creates temperature and pressure differences which causes the air

to move. If we break heat down into its basic form, it becomes energy. Heat is the total energy of allmolecules within a substance. These molecules are constantly in motion because of the heat differ-ences. Heat is a relative term, particularly when expressed as temperature.

There are four principal ways in which heat is transferred from one place to another. These fourmethods are conduction, convection, advection, and radiation. When a molecule is heated and comesin contact with another molecule, the second molecule absorbs some of this heat. This is heating bydirect contact and is called conduction. Convection is the heat transfer by vertical motion. In sum-mer, air over a hot runway or a highway will rise. Air over hot surfaces rises faster than the air oversurrounding surfaces. Parcels of air have a certain temperature, and when the wind blows, this aircomes in contact with other parcels of air. This process is the lateral transfer of heat and is called ad-

vection. The last heat transfer is the heat energy from the sun, and it is called radiation. These fourprocesses of heat transfer are very important in the process of weather.

Temperature is a measure of molecular motion expressed on a man-made scale, either in Fahren-heit (F), Celsius (C), or Kelvin (K). Fahrenheit's freezing point is 32° and its boiling point is 212°.The freezing point of Celsius is 0° and its boiling point is 100°. The Kelvin freezing point is 273°and its boiling point is 373°. Kelvin is used for scientific purposes.

Converting back and forth from Fahrenheit and Celsius is very simple if you have a formula touse. Any of these three formulas will work.

F = (C x 1.8) + 32 or C = F - 32 � 1.8 or F = (9/5) C + 32There is another conversion procedure which can be helpful; take a Celsius temperature and dou-

ble it, then subtract 10%, then add 32. This will work as well.Example: if C = 100, then F=212. Use one of the formulas to determine this. (see associated Ac-

tivity six at the end of the chapter.)Do aircraft pilots really care about what the temperature is? You better believe they do! Particu-

larly in extreme conditions. In other words, when temperatures are either really cold or really hot, pi-lots are most concerned. Why is this the case? Well, for one thing, temperature affects takeoff. Anexplanation follows.

You will recall that the sun heats the earth un-evenly. This unequal heating gives us temperaturedifferences which, in turn, causes pressure differ-ences. The different temperature and pressure char-acteristics mean that the parcels of air have differentmolecular make up and weigh different amounts, ex-erting different amounts of pressure. Pilots musttake this into account when preparing for takeoff.

Warmer temperatures result in longer accelerationtimes to attain proper takeoff speeds. On extremelyhot days the air can become very humid. A pilotneeds to calculate the distance needed to make surethere is enough runway for takeoff.

Understanding temperatures becomes crucial when they are extreme. Extreme hot and cold tem-peratures can cause pain discomfort and even death. Extreme heat can cause heat cramps (especiallyin legs), fainting (quick drop in blood pressure), heat exhaustion (dizziness after several hot days),and heatstroke (confusion, unconsciousness, or even death). Drinking plenty of water when it is ex-tremely hot can offset negative physical conditions.

High temperatures impact takeoffs of large aircraft.

15

In extreme cold, hypothermia and frostbite may occur. In hypothermia, the body temperaturedrops below 95° and a person can become unconscious and even die. Wearing wool clothing de-creases body heat escape, thus reducing the chance of hypothermia. Frostbite can range from veryminor to very serious cases. Ears, nose, hands, and feet are the most vulnerable. Gloves, hats, drysocks, and a covering for the face help prevent frostbite. (see associated Activities seven and Eightat the end of the chapter.)

PRESSUREThe last area in this chapter is pressure. We already know that unequal heating creates pressure

differences. Our air is made up of gases. Each of these gases has molecules, and these moleculeshave weight. This weight, or push on the Earth's surface, is called atmospheric pressure. Theweight, or atmospheric pressure, in a given space depends on the number of molecules occupyingthat space. There are literally billions of molecules near the Earth's surface. It has been said that amolecule travels less than one millionth of an inch before it collides with another molecule. This col-liding causes additional movement. Because it is so crowded, there is always molecular movementnear the surface of the Earth.

Another area where we notice pressure changes is our body, particularly our ears and sinuses. Ourbodies have trouble adjusting to rapid decreases or increases in pressure. Airplanes or even elevatorscan make us physically uncomfortable. When an airplane is taking off, the outside pressure de-creases so the pressure inside our ear is higher. Also, when a plane is landing, the outside pressureincreases so the pressure inside our ear is lower. Normally, air can move through the ear and equalizethe pressure. However, if you have a cold and your ears are blocked or you have blocked sinuses, theair can't equalize and you may feel some discomfort or pain. If you have a severe cold or sinus prob-lem, you should consider consulting a doctor before flying.

Air pressure can be measured with a mercury barometer, an aneroidbarometer, or an aneroid barograph. An aneroid barometer is fast andeasy to read. Aneroids are the barometers people have on their walls athome or in their office. A mercury barometer is not as quick, but is morestable and reliable. A mercury barometer is mainly used by scientists andmeteorologists. An aneroid barograph can be found in weather stationsall over the country because it gives a permanent record of pressurereadings. A permanent record is important if pressure readings need tobe reviewed due to severe weather or an aircraft accident.

Syphon Cell

Recording Pen

Pen Release Rod Pen Arm LinkageRevolving Drum

Mercury

Air Pressure

Indicator

Mercury Forced Up

Aneroid Barograph

Aneroid barometer

Mercury Barometer

16

Activity Five - Wind GaugePurpose: make and test a simple wind gauge.

Materials: clear plastic drinking straw (clean and dry), styrofoam cup, twostraight pins, piece of cardboard (about 3x12 inches), transparent tape, andExacto knife or scissors (caution – adult supervision advised)

Procedure:

1. Cut a piece of styrofoam from a styrofoam cup slightly larger than thediameter of the straw.

2. Roll the piece of styrofoam between your finger and thumb until itforms a ball that will move freely inside the straw.

3. Cut a notch in the straw about a half inch from one end to allow air toenter. (This notch will designate the front of the straw.)

4. Cut another piece of styrofoam and place it in the end of the strawbelow the notch to plug up the hole.

5. Cut a small hole in the side of the straw near the opening at the otherend of the straw to allow air to escape when you are measuring higherwinds.

6. Place the straw on the center of the cardboard with the open straw end meeting the top of the card-board and the hole facing the side. The notched end will hang a bit below the bottom of the card-board with the notch facing forward.

7. Press one of the pins through the straw and cardboard, just above the notch.8. Drop the ball into the other end of the straw.9. Press the other pin through the top of the straw and the cardboard, just below the small side hole you

cut for the high range. 10. securely fasten the straw to the cardboard with a couple of strips of transparent tape.11. Label the cardboard, as shown on the illustration, with the words Low Range and High Range. The

numbers on the illustration will be added as your gauge is calibrated by determining the correspon-ding speed with the movement of the styrofoam ball.

12. To calibrate (or establish and mark the units on a measuring instrument) your wind gauge, hold itoutside a moving car window on a calm day. Have the open notch at the bottom of the straw fac-ing into the wind. Air entering here will lift the styrofoam ball to various heights depending onthe speed of the air (determined by the speed of the vehicle). Use the vehicle’s speedometer tomark the card. Determine low range markings by having the vehicle driver go 1 mph and markthe height of the styrofoam ball. Then, do the smae for 2 mph, 3 mph, and so on until you reach12 mph. To determine high range markings, hold your finger over the top of the straw. This willkeep the ball from rising as high and forces the air to leave through the small hole you cut nearthe top. Follow the same markings procedure as for the low range, but use the illustrated mph

33

17

speeds. Another way to calibrate would be to go to your local weather station and measure yourgauge against their equipment.

Summary: The wind gauge is used to measure the approximate speed of the wind. Knowing thewind speed, or forecasting a wind speed, gives a good idea of how the wind will affect the land andsea. Knowing wind speed helps pilots appropriately adjust their takeoff, cruise, and landing speeds.If the winds are too high, flights may be cancelled, or planes may have to land at alternate landingsites.

Activity Six - Convert TemperaturesPurpose: Use mathematical skills to convert temperatures from Fahrenheit to Celsius and vice-versa.

Materials: Use formulas found on page 14 to conduct this activity.

Procedure: Convert temperatures

1. Convert the following Fahrenheit temperatures to Celsius:22° F = ___ C, 55° F = ____C, 75° F = ____C

2. Convert the following Celsius temperatures to Fahrenheit:45° C = ____F, 4° C = ____F, 82° C = ____F

Summary: Pilots are concerned about extremely cold and hot temperatures as temperature affects flight,and, thus, need to be able to quickly convert temperature measurement scales, as appropriate, to main-tain current temperature data for flight planning. By using the appropriate mathematical formula, conver-sion of temperature from one scale to another is possible. F = (C x 1.8) + 32 and C = (F – 32) ÷ 1.8Answers to problems (rounded to nearest whole number): 1. 22°F = - 6 °C; 55°F = 13°C; 75°F = 24°C

2. 45°C =113 °F; 4°C = 39 °F; 82°C = 180 °F

Activity Seven - Homemade ThermometerPurpose: Construct and test a homemade thermometer to determine heat or cold.

Materials: clear glass bottle (pint or quart), cork or stopper with one hole to fit a drinking straw, clearplastic drinking straw, 3x5 inch card, pencil, water, food coloring, candle, matches, transparent tape, oil(any kind), a medicine dropper, and thermometer

Procedure:

1. Fill the bottle with water and add a few drops of food coloring.2. Push the straw through the hole in the cork.3. Press the cork down into the bottle. make sure that about two inches of the straw are in the water.4. Light the candle and hold it so that the wax drips where the straw meets the cork to seal the straw to

the cork. (Adult supervision suggested.)5. The level of the water should be about one-fourth of the way up the straw.6. Use the medicine dropper to add more colored water into the straw.7. Add a couple of drops of oil to prevent the water from evaporating.8. Use tape to fasten the card behind the straw.9. To calibrate your thermometer, place another thermometer alongside yours and mark the level on the

card. mark the degrees from the known thermometer.

18

10. Experiment with the thermometer by moving it to differing levels oftemperature (in sun, in refrigerator, in closet, etc).

Summary: The higher the liquid rises in the straw, the hotter the tem-perature. The lower the liquid in the straw, the lower the temperature. Pi-lots are concerned about extremely cold and hot temperatures astemperature affects takeoffs and landings. Additionally, extremely coldtemperatures can impact a flight in route to a destination.

Activity Eight - Cricket ThermometerPurpose: The purpose of this activity is to use observation and mathe-matical skills to estimate temperature.

Materials: chirping cricket, clock or watch with a second hand, a warm day/evening, and a thermometer

Procedure:

1. On a warm day or evening, listen for the sound of a chirping cricket. 2. Use the watch or clock, count the number of chirps in 15 seconds and add 37 to this number. This sum

should just about equal the actual temperature.3. To find out, compare with an actual thermometer.4. Discuss why or how it may be possible for a cricket (or other living thing) to be so aligned with the

environment.

Summary: This activity is a fun way to estimate temperature, if you have a warm day/evening and achirping cricket. The implications of varying temperature, especially to pilots, has been explained in thischapter. But, fun activities, such as this, help us to see how nature is well-planned to “work” in thescheme of life.

12

3

6

9

19

Learning Outcomes

- Describe the condensation process.

- Describe how saturation occurs.

- Define dew point.

- Define what precipitation is and give some examples.

- Define fog.

- Define turbulence.

Important Terms

condensation - the process of converting water vapor to liquid

dew point - the temperature at which the air becomes saturated with water vapor

fog - tiny droplets of liquid water at or near the surface of the land or water

humidity - amount of water vapor in the air

precipitation - general term given to various types of condensed water vapor

relative humidity - amount of water vapor in the air compared to its water vapor capacity at a given

temperature

saturation - the condition of a parcel of air holding as much water vapor as it can at the air tempera-

ture at that time

water cycle - continuous movement of water as it circulates between the Earth and its atmosphere

MOISTUREWithout moisture in the atmosphere, weather could not exist. moisture is the most important ele-

ment in the development of the weather. It is the main component for clouds, rain, snow, and fog.

moisture exists in three states: solid, liquid, and gas. As a gas, it is called water vapor. Water vapor is

always present in varying degrees in the atmosphere. When the air gets to the point where it is hold-

ing all of the water it can, saturation is reached. Saturation is defined as the air holding as much

water vapor as it can at the air temperature at that time. The temperature at which the air becomes

saturated is called the dew point. This is not a fixed point. It changes several times a day depending

on the amount of moisture in the air. If the temperature decreases below its dew point, condensation

occurs. Or, if a parcel of saturated air receives more water, it condenses into liquid form. The conver-

sion of water vapor to a liquid is called condensation. Clouds, fog, snow, and rain are products of

condensation. (see associated Activity Nine at the end of the chapter.)

Another important term is humidity. Humidity is the term used for the amount of water vapor in

the air. When someone talks about how humid it is, they are really describing the relative humidity.

Relative humidity is the amount of humidity in the air compared to its total water vapor capacity at

44

a given temperature. It is expressed in a percentage. The higher the percentage, the more humidity.

(see associated Activity Ten at the end of the chapter.)

FOGAs mentioned earlier, one form of

condensation is fog. Fog is composed

of tiny droplets of liquid water that are

at or near the surface of the geographi-

cal area. It is actually a cloud that is

very near, or touching the ground.

Generally, fog forms when the temper-

ature and dew point are within five de-

grees of each other and the winds are

light (five knots or less). (see associ-

ated Activity Eleven at the end of the

chapter.)

Pilots frequently encounter fog,

and it mostly concerns them during

takeoffs and landings. Fog restricts

how well a pilot can see. many times when fog is present, pilots use their flight and navigation in-

struments to gauge distances both horizontally and vertically.

PRECIPITATIONAnother product of condensation is precipitation. Precipitation is the general term given to the

various types of condensed water vapor that fall to the Earth's surface such as rain, snow, or ice. Pre-

cipitation that falls to the ground as a liquid and stays in liquid form is called rain.

Precipitation affects flying mainly through the pilot's visibility and the runway conditions. The

harder it rains, the more it reduces the

visibility, and the more it diminishes

good runway conditions for both take-

off and landing. (see associated Activ-

ity Twelve at the end of the chapter.)

Precipitation that falls to the ground,

but freezes upon contact with various

surfaces, such as the ground, a high-

way, or cars, is called freezing rain.

Freezing rain can cause hazardous con-

ditions. Ice on car windshields and on

highways poses major problems for

motorists. Extreme caution should be

taken in icy conditions.

Ice can also represent huge prob-

lems for aircraft. First of all, ice on the

20

Fog rolling in under the Golden Gate Bridge

Flying in snow and icy conditions

21

runway can raise havoc with a plane trying to land. The plane

can lose directional control and take much longer to come to

a full stop, causing possible accidents.

Another critical condition could be ice in the airplane's en-

gine. In this case, ice can form in the carburetor, thus reduc-

ing or stopping fuel flow to the engine. Engine manufacturers

recommend that carburetor heat be applied to help solve the

ice problem.

Ice can also form on a plane's windshield, propeller, or

wings. If left to accumulate, it could cause weight, lift, and

visibility problems. Pilots will quickly change flying altitude

to get away from the ice. Also, weather forecasters will brief

pilots on possible icy conditions before they take off.

WATER CYCLEThe water cycle is the con-

tinuous movement of water be-

tween the Earth and its

atmosphere. Water is always

moving and changing from a

liquid to vapor and back to liq-

uid or snow and ice. The sun

heats the oceans and lakes

causing water to evaporate.

The water rises and becomes

water vapor, then eventually

condenses into tiny droplets

forming clouds. When clouds

meet cool air, precipitation can

occur. some precipitation

soaks in the ground and other

falls back into the oceans, and

the circulation continues. This

picture is a good illustration of

the water cycle.

Moist Air

Fuel

Ice

To engine

Carburetor Icing

Courtesy of National Oceanic and Atmospheric Association (NOAA)

22

CLOUDS

Another phenomenon which results from condensation is clouds. Clouds are made up of minutedroplets of water, or tiny crystals of ice, or both. Clouds are of continual interest to meteorologistsbecause they are visible indications of what is going on with the weather. The more we learn aboutclouds, the more we learn about the weather and what to expect. (see associated Activity Thirteen atthe end of the chapter.)

There are three basic cloud forms: cumulus, stratus, and cirrus. Clouds are classified by their ap-pearance and height. Cumulus clouds are normally white, billowy, puffy clouds. some describe themas cotton balls. Cumulus is a fair weather cloud indicating good weather. stratus has a very uniformappearance. It is thin with very little vertical development. It is almost sheet-like in its appearance.stratus is gray instead of white. Cumulus and stratus are both found low in the sky and close to theground. Cirrus clouds are very high in the sky. They are white, thin, wispy clouds, usually in patches,filaments, hooks, or bands. Because of their height, they are composed of ice crystals.

There are also ten basic cloud types that come from the three basic cloud forms. These ten basic

Cumulus Stratus

Nimbostratus

Middle Clouds

6000 m

High Clouds

Stratus

AltostratusAltocumulus

CirrocumulusCirrostratus

Cirrus

Veil

Cumulus

Cumulus(Fair Weather)

Clouds with Vertical Development

Cumulonimbus

(Anvil Head)

Stratocumulus2000 mLowClouds

Ten Basic Cloud Types

Cirrus

23

cloud types are universally accepted as the world'smain cloud types. The diagram on page 22 should giveyou an idea of what they look like and a general feelfor some of the differences. For instance, nimbostratusclouds produce rain that can last for hours.

An important cloud for helping us identify weatheris the cumulonimbus cloud. Cumulonimbus is the cloudthat produces storms with thunder and lightning. Thiscloud also produces heavy rain showers, strong winds,hail, and even tornadoes. Thunder and lightning comeonly from cumulonimbus clouds.

Another distinctive feature of cumulonimbus is themammatus development. This feature normally occursat the base of the cloud and looks like bulges orpouches. mammatus formations indicate the degree ofinstability in the area. Although not always, tornadoesoften come from these clouds. Even if tornadoes don'toccur, these clouds indicate severe weather.

Normally, clouds do not present a problem for air-planes. Pilots fly in and out of clouds all of the time.Obviously, an exception to this is the cumulonimbuscloud. Pilots don't want to fly into thunderstorms or tor-nadoes.

Cumulonimbus Clouds

Cumulonimbus Clouds

Mammatus formations under cumulonimbus clouds

24

In general, cumulus clouds are also associated with another weather phenomenon, and that is tur-bulence. Turbulence is an unrest or disturbance of the air. It refers to the instability of the air. Turbu-lence is the motion of the air that affects the smoothness.

Unstable air is turbulent air, whereas stable air is smooth with very little turbulence. Cumulus

clouds are formed by convection, which is defined as warm air rising. This rising warm air comes in

contact with cooler air causing the turbulence.

Pilots know that they will encounter turbulence when they fly through cumulus clouds. They also

know that turbulence can cause some very bumpy rides, especially in smaller planes.

CLOUD CLASSIFICATIONClouds are classified according to their height above and appearance (texture) from the ground.

The following cloud roots and translations summarize the components of this classification system:

1) Cirro-: curl of hair, high; 2) Alto-: mid; 3) strato-: layer; 4) Nimbo-: rain, precipitation; and 5)

Cumulo-: heap. Refer to the chart on page 22 for examples of the various types of clouds.

High-level clouds:High-level clouds occur above about

20,000 feet and are given the prefix "cirro."Due to cold tropospheric temperatures atthese levels, the clouds primarily are com-posed of ice crystals, and often appear thin,streaky, and white (although a low sunangle, e.g., near sunset, can create an arrayof color on the clouds). The three main typesof high clouds are cirrus, cirrostratus, andcirrocumulus.

Cirrus clouds are wispy, feathery, and composed of ice crystals. They often are the first sign of an

approaching warm front or upper-level jet stream. Unlike cirrus, cirrostratus clouds form more of a

widespread, veil-like layer (similar to what stratus clouds do in low levels). When sunlight or moon-

light passes through the hexagonal-shaped ice crystals of cirrostratus clouds, the light is dispersed or

refracted (similar to light passing through a prism) in such a way that a familiar ring or halo may

form. As a warm front approaches, cirrus clouds tend to thicken into cirrostratus, which may, in turn,

thicken and lower into altostratus, stratus, and even nimbostratus.

Finally, cirrocumulus clouds are layered clouds permeated with small cumuliform lumpiness.

They also may line up in "streets" or rows of clouds across the sky.

Mid-level clouds:The bases of clouds in the middle level

of the troposphere, given the prefix "alto,"

appear between 6,500 and 20,000 feet. De-

pending on the altitude, time of year, and

vertical temperature structure of the tropo-

sphere, these clouds may be composed ofAltocumulusAltostratus

Cirrostratus Cirrocumulus

25

liquid water droplets, ice crystals, or a combination of the two, including supercooled droplets (i.e.,

liquid droplets whose temperatures are below freezing). The two main types of mid-level clouds are

altostratus and altocumulus.

Altostratus clouds are "strato" type clouds (see previous page) that possess a flat and uniform type

texture in the mid levels. They frequently indicate the approach of a warm front and may thicken and

lower into stratus, then nimbostratus, resulting in rain or snow. However, altostratus clouds them-

selves do not produce significant precipitation at the surface, although sprinkles or occasionally light

showers may occur from a thick altostratus deck.

Altocumulus clouds exhibit "cumulo" type characteristics (see previous page) in mid levels, i.e.,

heap-like clouds with convective elements. Like cirrocumulus, altocumulus may align in rows or

streets of clouds, with cloud axes indicating localized areas of ascending, moist air, and clear zones

between rows suggesting locally descending, drier air. Altocumulus clouds with some vertical extent

may denote the presence of elevated instability, especially in the morning.

Low-level clouds:Low-level clouds are not given a prefix, although their names are de-

rived from "strato" or "cumulo," depending on their characteristics.

Low clouds occur below 6500 feet, and normally consist of liquid water

droplets or even supercooled droplets, except during cold winter storms

when ice crystals (and snow) comprise much of the clouds.

The two main types of low clouds include stratus, which develop

horizontally, and cumulus, which develop vertically. stratus clouds are

uniform and flat, producing a gray layer of cloud cover which may be

precipitation-free or may cause periods of light precipitation or drizzle.

Low stratus decks are common in winter in the Ohio Valley, especially

behind a storm system when cold, dismal, gray weather can linger for

several hours or even a day or two. stratocumulus clouds are hybrids of

layered stratus and cellular (individual) cumulus, i.e., individual cloud

elements, characteristic of cumulo-type clouds, clumped together in a

continuous distribution, characteristic of strato-type clouds. stratocumu-

lus also can be thought of as a layer of cloud clumps with thick and thin

areas. These clouds appear frequently in the atmosphere, either ahead of

or behind a frontal system. Thick, dense stratus or stratocumulus clouds

producing steady rain or snow often are referred to as nimbostratus

clouds.

In contrast to layered, horizontal stratus, cumulus clouds are more

cellular in nature, have flat bottoms and rounded tops, and grow verti-

cally. In fact, their name depends on the degree of vertical development.

For instance, scattered cumulus clouds showing little vertical growth on an otherwise sunny day

used to be termed "cumulus humilis" or "fair weather cumulus," although normally they simply are

referred to just as cumulus or flat cumulus. A cumulus cloud that exhibits significant vertical devel-

opment (but is not yet a thunderstorm) is called cumulus congestus or towering cumulus. If enough

atmospheric instability, moisture, and lift are present, then strong updrafts can develop in the cumu-

Stratocumulus

Cumulus congestus

Nimbostratus

26

lus cloud leading to a mature, deep cumulonimbus cloud, i.e., a thunder-

storm producing heavy rain. In addition, cloud electrification occurs

within cumulonimbus clouds due to many collisions between charged

water droplet, graupel (ice-water mix, much like hail), and ice crystal

particles, resulting in lightning and thunder.

THE LENTICULAR CLOUDS — FORMING ON ONE SIDE — GOING AWAY ON THE OTHER SIDE!

Lenticular clouds, technically known as altocumulus standing lenticularis, or ACsL, are station-

ary lens-shaped clouds that form at high altitudes, normally aligned at right angles to the wind direc-

tion.

When stable moist air flows over a range of mountains, a series of large-scale standing waves

may form. Under certain conditions, long strings of lenticular clouds can form, creating a formation

known as a wave cloud.

Power pilots tend to avoid flying near lenticular clouds because of the turbulence of the rotor sys-

tems that accompany them, but sailplane pilots actively look for them. This is because the systems

of atmospheric standing waves that cause "lennies" (as they are sometimes called) also involve

large vertical air movements, and the precise location of the rising air mass is fairly easy to predict

from the orientation of the clouds. This vertical air movement gives a glider lift that takes it to a

higher altitude.

No, it’s not an alien spacecraft. It’s known as a “lenticular cloud,”

or an “altocumulus standing lenticular” or ACSL cloud.

Cumulonimbus

27

An altocumalus standing lenticular cloud simultaneously

forming and dissipating above Mt. Rainier.

"Wave lift" of this kind is often very smooth and strong, and enables gliders to soar to remarkable

altitudes and great distances. some gliders have soared as far as over 1,500 miles and as high as

about 50,000 feet.

The picture below depicts an altocumulus standing lenticular over mt. Rainier in Washingtonstate, just south of seattle. The cloud, although it looks like it is standing still, is actually forming onone side and dissipating on the other. These clouds look this way because cloud-forming vapor con-denses by going below dew point at the crest of the waves. The lenticular clouds are known to fore-shadow bad weather. When airline pilots see these in the distance, the “seat belt” light goes onimmediately and a voice comes over the speaker saying, “Ladies and gentlemen, we may be experi-encing turbulence soon so please take your seats and fasten your seat belts!”

28

44Activity Nine - Dew Point

Purpose: Conduct an experiment to visually demonstrate the concept of dew point.

Materials: tin can, thermometer, tablespoon, ice cubes, paper towel, bowl, spoon, cool water, and salt

(optional - blender)

Procedure:

1. Place an ice cube on the paper towel.

2. Use the spoon to break the ice cube into small

pieces.

3. Place these pieces into the bowl.

4. Continue this process of breaking ice cubes until you

have about half a bowl full of crushed ice. (Or, use a

blender to crush ice all at once.)

5. Fill the can to about one-fourth full of cool water.

6. Place the thermometer in the can.

7. Add a tablespoon of crushed ice and stir.

8. Continue to slowly add ice and stir until a thin layer

of moisture, or dew, forms on the outside of the can.

9. Read the temperature as soon as the dew forms. This is the dew point.

10. If you add salt to the ice and stir, the moisture will turn into frost because the salt lowers the tempera-

ture of the dew to freezing.

Summary: This activity reinforces the concept explained in this chapter regarding dew point. The

dew point affects weather, which, of course, is of concern to pilots. Also, as explained at

http://www.flyingsafer.com/test%20report.htm, “A major cause of shortened engine life is water that

forms inside an internal combustion engine when it is not running. If the metal parts of the engine

ever cool to a temperature that is lower than the dew point temperature of the air inside your engine,

water droplets will form on the cool engine parts. This same process that causes dew to collect on

your automobile in the morning is collecting water inside your engine. If you can do something to

upset this process of changing temperatures and humidity levels (such as lowering the dew point

temperature of the air inside the engine to a temperature considerably below the outside air tempera-

ture), you can prevent water from ever forming inside your engine.”

stepsstep

29

Activity Ten - Comfort and Humidity

Purpose: Use observation skills to experiment with humidity,

which is discussed in chapter four.

Materials: plastic bag or empty bread wrapper, tape, and

room-temperature water

Procedure:

1. Place one hand in the plastic bag.

2. seal the bag snugly around your arm with tape, making the

bag airtight.

3. Leave the bag in place a few minutes and observe your

hand as it begins to sweat.

4. Wet your other hand with the room-temperature water. Both

hands are wet, but the one in the bag feels uncomfortable

while the other hand feels cool.

5. Discuss possible reasons for the difference in the “comfort”

of the two types of dampness.

Summary: The hand outside the bag feels wet, but comfortable. The hand inside the bag feels wet, un-

comfortable, and probably sticky. This is because the humidity is too high inside the bag. Humidity af-

fects the weather, which, in turn, is of great concern to pilots. Also, humidity can affect the properties of

materials both inside and outside the airplane. Inside the cabin, the relative humidity is kept low to help

prevent corrosion. Due to the low humidity inside the cabin of an aircraft, passengers may want to wear

eyeglasses as opposed to contact lenses that can become dried out. Also, passengers may wish to bring

moisturizer for the face and/or hands on long flights.

Activity Eleven - Making Fog

Purpose: Demonstrate how fog forms.

Materials: clear glass jar, tea strainer, ice cubes, and hot water

Procedure:

1. Fill the jar half full of hot water.2. Place the strainer over the opening of the jar.3. Fill the strainer with ice cubes and fog will form

inside the jar.

Summary: With this activity, it is easy to see howeasily fog can form. This fog is formed when a layerof warm, moist air forms low to the ground. A layer ofcooler, dry air (ice) forms overtop, cooling thewarmer air quickly. As the air temperature lowers,small droplets of water condense, and is seen as fog.

step

steps

Activity Twelve - Measuring Precipitation Purpose: make and use a rain gauge to measure precipitation.

Materials: a 1-pound coffee can, olive jar, ruler, marking pen, water, funnel, and a watch

Procedure:

1. Place the ruler into the coffee can.2. Pour 2 inches of water into the can, using the 2-inch mark on the ruler as your gauge.3. Place the funnel into the top of the olive jar.4. Pour the 2 inches of water from the can into the jar.5. mark the water level on the outside of the jar.6. Discard the water in the jar.7. Use the ruler to divide the space below the mark on the jar into 20 equal spaces. (This divides the

space into tenths, with each mark representing one-tenth of an inch of rain.)8. Place the coffee can in an open area away from trees and buildings to collect rain water.9. After the rain stops, use the funnel to pour the rain water from the can into the jar.10. Read the marks on the jar to determine the amount of rain that fell.

Summary: This is a great exercise for keeping an accurate account of how much rain is falling or hasfallen. It is standard practice to measure rainfall for an hour, 6 hours, or even a day or month. Whenusing the rain gauge, remember to record your measurements and then dump out the rain so that it doesn’t get counted again. measuring precipitation is a regular action of meteorologists to help the pub-lic stay abreast of agricultural, transportational, and recreational impact.

Activity Thirteen - Cloud in a Bottle

Purpose: simulate cloud formation, as discussed in chapter four.

Materials: glass jug with a small mouth and a match or candle (Note: adult supervision suggested.)

Procedure:

1. Light the match or candle. (Adult supervision required)2. Turn the jug upside down and carefully hold the opening over the flame.3. Warm the air inside the jug for a few seconds.

30

steps steps stepsteps

steps

5

31

4. Blow out the match or candle.5.Quickly place your mouth around the opening to make

a seal.6. Blow hard into the jug, compressing the air inside thejug as much as possible. (Be careful not to breathe in, orthe compressed air will be released too soon.)7. Quickly remove your mouth and release the pressure.8. Observe the cloud that forms inside the jug.9. Discuss why/how this happens.

Summary: When you compressed the warm air in thejug, you also added the moisture from your breath.When you suddenly released the pressure, the air mole-cules in the jug cooled and expanded. The cooler aircouldn't hold as much moisture as the warmer air, thussome of the moisture condensed into tiny droplets andformed a cloud. In the atmosphere, these tiny waterdroplets, or ice crystals, cling to particles in the atmos-phere, such as salt, smoke, dust, and volcanic ash toform clouds.

steps

step

steps

32

Learning Outcomes

- Define an air mass and identify air mass characteristics.- Define a front and describe the types of fronts.- Describe hurricanes, thunderstorms, and tornadoes.- Identify the stages of a thunderstorm.- Outline safety precautions for thunderstorms and tornadoes.

Important Terms

air mass - huge body of air with the same temperature and moisture characteristics

front - a boundary between two air masses

hurricane - a tropical cyclone of low pressure and very strong winds; usually with heavy rain andpossible thunderstorms and tornadoes

thunderstorm - cumulonimbus cloud possessing thunder and lightning; usually accompanied bystrong winds, rain, and sometimes hail

tornado - whirling funnel of air of very low pressure and very strong winds; may be powerfulenough to suck up anything in its path; must touch the ground to be called a tornado

AIR MASSESWhen the meteorologist on television is talking about a large weather pattern or weather system

moving into your area, he/she is referring to an air mass or a front. An approaching air mass or front

will definitely influence and change the weather in your local area. This chapter takes a look at se-

vere weather and some of the effects of these phenomena.

An air mass is a huge body of air, usually 1,000 miles or more across, that has the same tempera-

ture and moisture characteristics. When an air mass travels out of its area of origin, it carries those

characteristics with it. The place of origin of an air mass is called its source region, and the nature of

the source region largely determines the initial characteristics of an air mass. The ideal source region

must be very large and the physical features must be consistent throughout. Land located next to

water is not a good source region. Tropical (frost free and high temperatures areas) and polar (colder

areas far from the equator) locations are the best source regions.

Air masses are classified by their source region and the nature of the surface in their source region.

They are identified by a two-letter code consisting of a lowercase letter and a capital letter. The lower-

case letter is either m (maritime) or c (continental). maritime stands for water (high moisture and wet),

and continental stands for land (low moisture and dry). The capital letter refers to temperature at lati-

tude and is placed into four categories: polar (P), arctic (A), tropical (T), and equatorial (E). The differ-

ences between polar and arctic (colder), and between tropical and equatorial (warmer) are very small.

55

33

Here are the air mass classifications:cA continental arcticcP continental polarcT continental tropicalmT maritime tropicalmP maritime polarmE maritime equatorial

(see associated Activity Fourteen at the end ofthe chapter.)

FRONTSFronts are classified as warm, cold, stationary, and occluded. A

warm front occurs when warm air moves into an area of colder airand they collide. The warm air overrides the cold because it is lighter.The heavier, colder air sinks.

Cold fronts occur when the air moving into the area is colder than thealready present warmer air. The heavier, colder air pushes the warmerair up and out of the way. In general, cold fronts move faster than warmfronts. so, the colder air is rapidly pushing the warmer air out.

sometimes different air masses bump against each other, but the dif-ference between them is not enough to force movement. This is called astationary front. Neither the warm nor the cold air advances, and it be-comes a standoff. This can last a few hours or a few days, but eventu-ally more forceful air will push into the area and create movement.

Occluded fronts involve three differing air masses and are classi-fied as either cold occluded or warm occluded. In the cold occluded,cold air moves in and collides with warmer air pushing the warm airaloft. Then, the leading edge of this cold front comes in contact withthe trailing edge of the cooler surface air that was below the warm air.Because the advancing air is the coldest, it sinks to the surface and causes the cooler air to rise.However, the cooler air is still cooler than the warm air, so it continues to push the warm air above it.

In the warm occluded front, cool air is advancing to collide with the air in your area. since the coolerair is warmer than the colder surface air, the cooler air rides up over the cold air. Once again, though, thecooler air is cooler than the warm air that was already aloft, so the cooler air continues to push thewarmer air up.

In color weather maps, cold frontsare identified by the color blue andwarm fronts by the color red. stationaryand occluded fronts are red and blue.(see associated Activities Fifteen andsixteen at the end of the chapter.)

This is how fronts appear

on weather maps:

OccludedWarm FrontStationaryCold Front

cA cAcP cP

cT

cT

cT

mP

mTmT

FRONT

A Warm Front

A Cold Front

FRONT

A Cold Occluded Front

WARM

WARM

WARM

COLD

COLD

COLD COOL

FRONTWA

RM

A Warm Occluded Front

COOL COLD

FRONT

FRONT

FRONT

SEVERE WEATHERThe last section of this chapter is severe

weather. There are three main weather phe-nomena to discuss in this area: thunderstorms,tornadoes, and hurricanes. All three are pow-erful, devastating phenomena that damageproperty and bring destruction. All three aredangerous and potentially deadly, as well.This section will give you information aboutthese three severe weather phenomena andhelp you prepare for them.

spotting a cumulonimbus cloud, like theone pictured here, is a sign of severe weatherconditions. All three of our severe weatherphenomena can be associated with cumu-lonimbus clouds.

ThunderstormsThunderstorms come from cumulonim-

bus clouds and always possess thunder andlightning. The most spectacular and danger-ous part of a thunderstorm is the lightning.Lightning is the flash of light produced byelectrical discharges in a thunderstorm area.Lightning discharges millions of volts of elec-tricity and heats the air to 60,000°F. Lightningcan vary from between 9 to 90 miles. Thunderis the sound sent out by rapidly expandinggases along the lightning’s trail. Thunder-storms usually contain heavy rain, strongwinds, and sometimes hail (small balls of ice).Thunderstorms have three stages: building,mature, and dissipating. The building stage isdominated by updrafts as the storm builds andgrows vertically. Eventually, the moisture thatis carried up with the storm gets heavier andstarts to fall. This creates downdrafts. Up-drafts are still occurring, so the moisturemoves up and down several times. This activ-ity describes the mature stage. The last stagehas downdrafts only and this is called the dis-sipating stage. (see associated Activity seventeen at the end of the chapter.)

At any given time in the world, 2,000 thunderstorms are occurring, and from these storms 100lightning strikes occur per second. Thunderstorms can occur anytime, anywhere. There is an old say-ing that lightning does not strike twice in the same place. Don't believe it! The Empire state Buildinghas been struck many times during the same storm.

34

Cumulonimbus Cloud

Hail

Building Mature Dissipating

Lightning can kill. On the av-erage, over 200 people are killedevery year in the U.s., and an-other 500-600 people are injuredby lightning strikes.

Let's take a moment and re-mind ourselves of some safetyrules for thunder and lightning.During a storm, following thislist will increase your safety:

• When inside, stay away fromwindows and doors.

• Don't use electrical appliances.

• Don't use the telephone or takea shower or bath.

• If outdoors, go inside if youcan.

• move away from water, suchas swimming pools and lakes.

• If you are in a boat, go ashore.

• stay away from metal objectslike golf clubs, fishing poles,bicycles, farm equipment, ormotorcycles.

• Don't stand in an open field, ahilltop, or on a golf course(stay low by sitting or crouch-ing).

• Don't stand under a single tree(if you must be under a tree,look for a clump of small treesor trees of similar height).

• If in a group of people, staylow and spread out.

• If in a car, stay there.

Thunderstorms present sev-eral challenges to pilots. Thun-derstorms come from cumulonimbus clouds, and that means there is unstable air present. so,thunderstorms have violent up and down drafts. As already mentioned, unstable air causes turbu-lence, and turbulence, particularly heavy turbulence, raises havoc with planes.

Thunderstorms generally bring rain, usually heavy, and sometimes even hail. Hail can do seriousdamage to airplanes. Also, thunderstorms are always accompanied by thunder and lightning. Pilotsare well aware of the dangers associated with thunderstorms and usually fly above or around them.

35

Lightning near Eglin AFB

Vertical & horizontal lightning (NASA)

TornadoesOne of the most severe weather phenomenon is the tornado. A tornado is very destructive and can

be devastating to life and property. Tornadoes have occurred in every month of the year and in everystate in the Us About 700 tornadoes are reported in the Us annually.

Tornadoes consist of unstable air of very low pressure. most tornadoes move in a counterclock-wise manner. Air is sucked into the center, or vortexof the storm, and is rapidly lifted and cooled. Thefunnel of a tornado appears very dark as it movespicking up dirt and debris.

Tornadoes will normally touch down for severalmiles then go back up in the cloud, and then touchdown again later. It will do this many times duringits life. A tornado ranges from 50 to 500 yards wideand moves across the ground at about 70 mph.These are just averages, as they can move twice asfast, or as slow as 5 mph.

A tornado's winds can be stronger than 300 knots(each knot is equal to one nautical mile, which isabout 1.151 mph), and this is the main reason for thetremendous destruction associated with tornadoes.The Fujita Wind Damage scale, shown below, ex-plains the categories of wind speed and expecteddamage.

If you know a tornado is coming, thereare precautions you can take:

• If time permits, get to a basementor underground.

• If in open country, move at rightangles (90°) away from it.

• If there is time, get to a low place,like a ditch, and lie down.

• If indoors, stay away from win-dows, and if you don't have a basement, get to an interior hallway, closet, or bathroom.

HurricanesAnother severe phenomenon is the hurricane. A good case could be made for hurricanes as being

the most dangerous of storms. First of all, they produce many thunderstorms and tornadoes withintheir system. secondly, although their winds are not as strong as a tornadoes, they are often above100 knots. Hurricanes affect a large area, hundreds of miles wide, and they usually continue for morethan a week. many times they will flood coastal cities and dump many inches of rain. The winds,along with the tidal waves from the ocean, demolish homes on a routine basis.

Before tropical cyclones develop into hurricanes, they can be divided into three categories de-pending on the wind speed. The lowest category is a tropical disturbance, then a tropical depression,and finally a tropical storm. A tropical storm's winds must be between 39 and 74 mph. If the winds

36

Tornado

Fujita Wind Damage Scale

Number Wind Speed Damage

F-0 Up to 72 mph lightF-1 73 to 112 mph moderateF-2 113 to 157 mph considerableF-3 158 to 206 mph severeF-4 207 to 260 mph devastatingF-5 above 261 mph incredible

go above 74 mph, the cy-clone is called a hurricane.Hurricanes have five cate-gories. These categories arepresented on the saffir-simp-son Hurricane Damage Po-tential scale (shown below).Although the winds are whatmost people pay attention to,this scale also mentions thebarometric pressure and thestorm surge. Hurricane dam-age comes from the winds,storm surges, and flooding.

One distinctive feature ofevery hurricane is the eye.The eye is the center of thestorm. It consists of calm orvery light winds and clearskies or very few clouds. It iscalm and peaceful, yet sur-rounded by violence and force on all sides. The average eye of a hurricane is about 10-15 mileswide. After the eye passes, the winds roar and blow as strong as before. (see associated Activity Eighteen at the end of the chapter.)

37

Hurricane

Even the strongest of trees are no match for the fury of hurricane or tor-

nado winds.

The eye of a hurricane

Saffir-Simpson Hurricane Damage Potential Scale

Category 1 Category 2 Category 3 Category 4 Category 5

Pressure 28.94 28.50-28.91 27.91-28.47 27.17-27.88 27.17 Wind 75-95 mph 96-110 mph 111-130 mph 131-155 mph 155 mphStorm Surge 4-5 ft 6-8 ft 9-12 ft 13-18 ft 18 ft

38

55Activity Fourteen - Air Masses

Purpose: Identify types of air masses indicated on a map.

Materials: map to right and matching columns below

Procedure:

1. Identify the type of air masses on the map. (Refer topage 33 for assistance and answers.)

2. match the air mass characteristics (Column A) with its source region (Column B).

Column A Column B

____ (1) Very moist and very warm air mass a. cA

____ (2) Exceptionally cold; very dry air mass b. cT

____ (3) Cool and moist air mass c. mP

____ (4) Very warm and dry air mass d. mT

Summary: This activity reinforces knowledge regarding types of air masses. Air masses are classifiedby their source region and the nature of the surface in their source region.Answers: 1) d. 2) a. 3) c. 4) b.

Activity Fifteen - Identifying FrontsPurpose: Practice identifying fronts.

Materials: questions and illustrations below

Procedure: Circle each correct answer. Use page 33 for reference.

1. What kind of front is this?a. Warmb. Coldc. stationaryd. Occluded

cAmP

cA

cT

cT

mP

mTmT

FRONT

WARM COLD

39

2 What kind of front is this?a Warmb. Coldc. stationaryd. Occluded

3. What kind of front is this?a. Warmb. Coldc. stationaryd. Occluded

Summary: This exercise is useful to review the identification of weather fronts. The important aspect tounderstand is which air is replacing, or pushing or lifting, which air.Answers: 1) a. 2) b. 3) d.

Activity Sixteen - Fronts on MapsPurpose: Practice reading and analyzing maps.

Materials: map and questions

Procedure:

Use the map below to answer the following questions.

1. What kind of front is approaching Atlanta, Georgia?a. Warmb. Coldc. stationaryd. Occluded

2. What kind of front is next to Bismarck, North Dakota?a. Warmb. Coldc. stationaryd. Occluded

3. In the next several hours, what will thetemperatures be in st. Paul, minnesotaand st. Louis, missouri?

a. Warmerb. Colder

Summary: This activity reinforcesweather map knowledge. Knowing whatfronts look like on a map can greatly aidforecasting skills, which is an importantskill for pilots.Answers: 1) a. 2) c. 3) b.

WARM

WARM

COLD

COLD COOL

FRONT

FRONT

FRONT

OccludedWarm FrontStationaryCold Front

Atlanta, Georgia

St. Louis, Missouri

St. Paul, MinnesotaBismarck, North Dakota

Activity Seventeen - Distance to a ThunderstormPurpose: Using observation and math skills, estimate the distance between you and a storm.

Materials: a watch or clock with second hand and a thunderstorm

Procedure:

1. Watch for a flash of lightning.2. Then count the number of seconds until you hear the thunder.3. Now divide the number of seconds by five. This gives you the

approximate number of miles to the storm. Light from the flashtravels to your eyes almost instantly, while sound travels at about1,100 feet per second. Example: 5 seconds is 5,500 feet, or a lit-tle more than 1 mile. If you don't have a watch, simply count"thousand one, thousand two, thousand three," and so on. Eachcount is a second and 5 seconds is 1 mile.

Summary: Knowing how to estimate the distance between you and an approaching storm is important.It gives you an idea of how quickly the storm is approaching or moving away. This knowledge may helpyou make important life-saving decisions.

Activity Eighteen - Matching Severe WeatherPurpose: Review your knowledge of severe weather.

Materials: matching columns below

Procedure: match the description in column A with the correct weather in column B.

Column A Column B

___ (1) Cloud which can produce severe weather

___ (2) First stage of a thunderstorm

___ (3) Can heat the air to 60,000° F

___ (4) What you do not do during a thunderstorm

___ (5) What you do not do during a tornado

___ (6) Cause of damage due to a hurricane

Summary: This matching exercise allows you to demonstrate your knowledge of severe weather andthe damages and precautions for each.Answers: 1) d. 2) f. 3) b. 4) i. 5) h. 6) a.

40

a. flooding

b. lightning

c. stratus

d. cumulonimbus

e. mature

f. building

g. thunder

h. go to the upstairs of your house

i. go golfing

4Aerospace Dimensions

ROCKETS

4Aerospace Dimensions

ROCKETS

MODULE

Civil Air PatrolMaxwell Air Force Base, Alabama

4

Aerospace Dimensions

ROCKETS

4

Aerospace Dimensions

ROCKETS

WRITTEN BY

DR. JEFF MONTGOMERY

DR. BEN MIllspauGh

DEsIGN

BaRB pRIBulICK

IllusTRaTIONs

pEGGY GREENlEE

EDITING

BOB BROOKs

susaN MallETT

JuDY sTONE

NaTIONal aCaDEMIC sTaNDaRD alIGNMENT

JuDY sTONE

puBlIshED BY

NaTIONal hEaDQuaRTERs

CIVIl aIR paTROl

aEROspaCE EDuCaTION DEpuTY DIRECTORaTE

MaXWEll aFB, alaBaMa 36112

ThIRD EDITION

JuNE 2013

INTRODUCTION

ii

The Aerospace Dimensions module, Rockets, is the fourth of six modules, which combined, makeup Phases I and II of Civil Air Patrol's Aerospace Education Program for cadets. Each module ismeant to stand entirely on its own, so that each can be taught in any order. This enables new cadetscoming into the program to study the same module, at the same time, with the other cadets. Thisbuilds a cohesiveness and cooperation among the cadets and encourages active group participation.This module is also appropriate for middle school students and can be used by teachers to supple-ment sTEm-related subjects.

Inquiry-based activities were included to enhance the text and provide concept applicability. Theactivities were designed as group activities, but can be done individually, if desired. The activitiesfor this module are located at the end of each chapter.

CONTENTS

iii

Last century launch vehicle ... Saturn V This century launch vehicle ... Ares I

Introduction .............................................................................................ii

Contents...................................................................................................iii

National Academic Standard Alignment ..............................................iv

Chapter 1. History of Rockets ................................................................1

Chapter 2. Rocket Principles, Systems and Engines...........................11

Chapter 3. Rocket and Private Space Travel ......................................27

iv

National Academic Standard Alignment

Learning Outcomes

- Identify historical facts about the Greeks, Chinese, and British, and their roles in the

development of rockets.

- Describe America's early contributions to the development of rockets.

- List the early artificial and manned rocket launches and their missions.

Important Terms/Persons Neil Armstrong - first man to walk on moonRoger Bacon - increased the range of rocketsWilliam Congreve - designed rockets for military useJean Froissart - improved the accuracy of rockets by launching them through tubesYuri Gagarin - a Russian; the first man in space and the first man to orbit the EarthJohn Glenn - first American to orbit the EarthRobert Goddard - experimented with solid and liquid propellant rockets; is called the “Father of

modern Rocketry”William Hale - developed the technique of spin stabilizationHero - developed first rocket engineSergei Korolev - the leading soviet rocket scientist; known as the “Father of the soviet space Program”Sir Isaac Newton - laid scientific foundation for modern rocketry with his laws of motionHermann Oberth - space pioneer; wrote a book about rocket travel into outer spaceAlan Shepard - first American in spaceSkylab - first Us space stationSpace Shuttle - a space transportation system for traveling to space and back to EarthSpin Stabilization - a technique developed by Englishman, William Hale, wherein escaping gases in

a rocket hit small vanes that made the rocket spin, and stablize, much like a bullet in flightSputnik I - first artificial satellite; RussianKonstantin Tsiolkovsky - proposed the use of rockets for space exploration and

became known as the “Father of modern Astronautics”Wernher von Braun - director of the V-2 rocket project

Today's rockets are remarkable examples of scientific research and experi-mentation over thousands of years. Let's take a moment and recall some of thefascinating rocket developments of the past.

HISTORYThe history of rockets began around 400 BC when a Greek named Archytas

built a flying wooden pigeon. It was suspended on a wire and propelled by escaping steam. About300 years later, another Greek named Hero developed the first rocket engine. It was also propelledby steam.

1

11

Hero Engine

Hero placed a sphere on top of a pot of water. The waterwas heated and turned into steam. The steam traveledthrough pipes into the sphere. Two L-shaped tubes on op-posite sides of the sphere allowed the gas to escape. Thiscreated a thrust that caused the sphere to rotate. This deviceis known as a Hero Engine. (see associated Activity One atthe end of the chapter.)

In the first century AD, the Chinese developed a form ofgunpowder and used it as fireworks for religious and festivecelebrations. The Chinese began experimenting with thegunpowder-filled tubes. They attached bamboo tubes to ar-rows and launched them with bows, creating early rockets.

In 1232, with the Chinese and mongols at war witheach other, these early rockets were used as arrows of fly-ing fire. This was a simple form of a solid-propellantrocket. A tube, capped at one end, contained gunpowder.The other end was left open and the tube was attached to along stick. When the powder ignited, the rapid burning ofthe powder produced fire, smoke, and gas that escaped outthe open end and produced a thrust. The stick acted as aguidance system that kept the rocket headed in one generaldirection as it flew through the air. Records indicate that from this point, the use ofrockets spread, as well as the use of fins to add greater guidance and stability.

Rocket experiments continued throughout the 13th to 15th centuries. In England,Roger Bacon improved forms of gunpowder, which increased the range of the rocket.In France, Jean Froissart achieved more accuracy by launching rockets throughtubes. This idea was the forerunner of the bazooka. (see associated Activity Two atthe end of the chapter.)

During the latter part of the 17th century, Sir Isaac Newton laid the scientificfoundations for modern rocketry when he developed his laws of motion. These lawsexplain how rockets work and are discussed in detail in Chapter 2 of this volume.

Newton's laws of motion influenced the design of rockets. Rocket experimenters inGermany and Russia began working with very powerful rockets. some of these rock-ets were so powerful that their escaping exhaust flames bored deep holes in theground even before liftoff.

At the end of the 18th century, Colonel William Congreve, an artillery expert withthe British military, set out to design rockets for military use. His rockets increasedthe rocket's range from 200 to 3,000 yards and were very successful in battle, not be-cause of accuracy, but because of the sheer numbers that could be fired. During a typi-cal siege, thousands of rockets could be fired. These became known as the Congreverockets, and were the rockets that lit the sky during the battle at Fort mcHenry in1812, while Francis scott Key wrote his famous poem, which later became our na-tional anthem, “The star spangled Banner.”

Even with Congreve's work, the accuracy of rockets still had not improved much.so, rocket researchers all over the world were experimenting with ways to improveaccuracy. An Englishman, William Hale, developed a technique called spin stabi-

lization. In this method, the escaping exhaust gases struck small vanes at the bottomof the rocket, causing it to spin much as a bullet does in flight. many rockets still usevariations of this principle today.

2

Fireworks and rockets

share a common heritage

Congreve Rocket

Early Chinese Rocket

3

MODERN ROCKETRY

In 1898, a Russian schoolteacher, Konstantin Tsiolkovsky, pro-posed the idea of space exploration by a rocket. He published a reportin 1903 suggesting the use of liquid propellants for rockets in order toachieve greater range. Tsiolkovsky stated that only the exhaust veloc-ity of escaping gases limited the speed and range of a rocket. For hisideas, research, and vision, Tsiolkovsky has been called the “Father ofmodern Astronautics.”

Early in the 20th century, an American physics professor, Dr.

Robert H. Goddard, conducted many practical experiments withrockets. His research led to major breakthroughs in the developmentof rockets. His earliest experiments were with solid-propellant rock-ets. Then he became convinced that liquid fuel would better propel arocket. In 1926, Goddard achieved the first successful flight with aliquid-propellant rocket. It was fueled by liquid oxygen and gasoline.This was the forerun-ner of today's rockets.

As he continuedwith his experiments,his liquid-propellantrockets grew biggerand flew higher. Healso developed a gyro-scope system for flightcontrol, a payloadcompartment, and aparachute recoverysystem. Additionally,he believed that multi-stage rockets were theanswer for achievinghigh altitudes. For hismany accomplish-ments, Dr. Goddard isknown as the “Fatherof modern Rocketry.”

IgniterNeedle valve

Liquid oxygen

line

Hinged rod

Exhaust shield

Pull cord

Alcohol burner

Gasoline tankPull cord

Pipe

Oxygen cylinderDetachable

starting hose

Check valve

Oxygen gaspressure line

Cork floatvalve

Liquid oxygen tank

Pressurerelief vent

Gasoline line

Rocket motor

Needle valve

Dr. Robert H. Goddard

Goddard Rocket Illustration

In 1923, Hermann Oberth of Germany, published a book about rockettravel into outer space. Because of his writings, small rocket societies werestarted around the world. In Germany, one such society, the society for spaceTravel, led to the development of the V-2 rocket.

The V-2 rocket, with its explosive warhead, was a formidable weaponwhich could devastate whole city blocks. Germany used this weapon againstLondon during World War II, but fortunately this occurred too late in the warto change the outcome. The V-2 was built under the directorship of Wernher

von Braun, a German,who after the war headed up the Us rocket program. With the fall of Germany, the Allies captured many unused V-2 rockets

and components. many German rocket scientists came to the United states.Others went to the sovietUnion. Von Braun andabout 120 of his scientistssigned contracts to workwith the Us Army. VonBraun and his team usedcaptured V-2s to teachAmerican scientists andengineers about rocketry.

In the soviet Union,Sergei Korolev was lead-ing Russian scientists inrocket development. Heorganized and led the de-velopment of the first suc-cessful sovietintercontinental ballisticmissile in August 1957.Two months later, the so-viet Union launched theworld’s first artificial satel-lite, Sputnik I. He is con-sidered to be the “Father of the sovietspace Program.”

Warhead(Explosive Charge)

Automatic Gyro Control

Guidebeam and RadioCommand Receivers

Container for Alcohol-water

Mixture

Container for Liquid Oxygen

PropellantTurbopump

Steam Exhaustfrom Turbine

AlcoholMain Valve

Rocket Motor

Oxygen Main Valve

Vaporizer for TurbinePropellant (Propellant

Turbopump Drive)

Container forTurbine Propellant

(Hydrogen Peroxide)

Air VaneJet Vane

Wernher von Braun

V-2 Rocket

4

5

Space Race

Both the United states and the soviet Union recognized

the potential of rocketry as a military weapon and began a

variety of experimental programs. The United states began

a program of high-altitude atmospheric sounding rockets.

Then the Us developed a variety of medium - and long-

range intercontinental ballistic missiles. These became the

starting points for the Us space program.

missiles, such as the Redstone, Atlas, and Titan, would

eventually launch satellites and astronauts into space. Col-

lectively, they were called rocket launch vehicles and they

were the real workhorses for the space program.

A launch vehicle is the rocket system that lifts a space-

craft. It gives the spacecraft enough force to reach orbit.

These launch vehicles propelled people and cargo into

space. The diagram to the right shows an example of a

rocket launch vehicles used by the Us space program.

As stated previously, on October 4, 1957, the soviet

Union launched into space the first artificial (man-made)

satellite, Sputnik I. The “race for space” between the two

world superpowers, the Us and the UssR, had begun.

On January 31, 1958, the Us launched Explorer I (il-

lustration on next page). The Explorer I was the first space-

craft to recongnize the Van Allen radiation belt around the

William Pickering,

James Van Allen, and

Wernher von Braun

displaying a full-

scale model of the

Explorer 1 satellite,

weighing only 30.80

lbs, at a crowded

press conference

held in the Great Hall

of the National Acad-

emy of Sciences at

1:30 A.M. February 1,

1958, when it was

confirmed that the

satellite was in orbit

around the Earth.Sputnik I

Titan III(23)C rocket launch (March 25,

1978) carrying two DSCS (Defense

Satellite Communications System)

II satellites (The Titan IIIC was the

launch vehicle for Voyager 1 and 2).

Earth held in place by Earth’s magnetic field. The Explorer I was launched then, in October 1958,

the Us formally organized its space program by creating the National Aeronautics and space Admin-

istration (NAsA). NAsA became the civilian agency with the goal of peaceful exploration of space

for the benefit of all humankind. The Department of Defense (DoD) became responsible for research

and development in the area of military aero-

space activities. Thus, the Us began to study

space exploration in earnest.

Both the Us and the soviet Union began

sending many people and machines into

space. In April of 1961, a Russian, named

Yuri Gagarin, became the first man to orbit

Earth. Then, less than a month later, Alan

Shepard, aboard his mercury capsule, Free-

dom 7, became the first American in space.

The Redstone rocket that propelled shepard

was not powerful enough to place the mercury

capsule into orbit. so, the flight lasted only 15

minutes and reached an altitude of 187 kilo-

meters (or 116 miles). Twenty days later, may

25, 1961, even though the soviet Union was

ahead of the Us in the space race, President

John F. Kennedy announced the objective of

putting a man on the moon by the end of the

decade.

In February 1962, John Glenn became

the first American to orbit the Earth aboard

the mercury capsule, Friendship 7. Glenn

was launched by the more powerful Atlas

rocket and remained in orbit for 4 hours and

55 minutes.

6

John Glenn's Mercury

capsule atop an Atlas

launch vehicle

Alan Shepard's

Mercury capsule atop

a Redstone rocket

Antenna

Geiger CounterInternal

TemperatureGauge

ExternalTemperature

Gauge

Nosecone withTemperatureProbe Inside

Instrument Compartmentwith Radio Transmitter

Rocket Engine

MicrometeoriteErosion Gauges

Explorer I

7

The Us then began an extensive unmanned space program aimed at supporting the manned lunar

landing program. The Atlas rocket continued to power these mercury missions until the larger Cen-

taur rocket booster was added to it and the Titan rockets. Although rocket staging had been used

since early rocketry began, this booster system added boosting stages to propel rockets even further.

As rocket building was refined, so was the capability of the Us to explore the moon. (see associated

Activity Three at the end of the chapter.)

Next came the Gemini missions in 1965-1966,

which were designed to carry two crew members.

These missions were launched by the largest

launch vehicle available, the Titan II. Gemini mis-

sions were aimed at expanding our experience in

space and preparing the U.s. for a manned lunar

landing on the moon. Gemini paved the way for

the Apollo missions by demonstrating rendezvous

and docking procedures.

After the Gemini missions, the third manned

space program, Apollo, began in 1967 and ended

in 1975. Launching men to the moon required

much larger launch vehicles than those avail-

able. so, the Us developed the saturn launch ve-

hicles; saturn I, IB, and V. The saturn I and IB

were large two-stage liquid-propellant launch

vehicles assembled from the components of

other rockets.

In October 1968, a saturn IB launched the first

three-person mission, Apollo 7. Then, the three-

stage saturn V was developed with one goal —

send humans to the moon. On July 20, 1969,

Apollo 11 landed on the moon, powered by the

saturn V launch vehicle, and Neil Armstrong be-

came the first man to walk on the moon.

The next space project of the United states

was Skylab - first Us space station. The saturn

V was used to launch Skylab into space. The sat-

urn IB launch vehicles were used to launch

crews to the space station. Skylab was launched

in may 1973 and had three separate missions be-

tween 1973 and 1974. The last mission was the

longest. It lasted 84 days.

After the space station, the Us concentratedon a reusable launch system, the space Trans-portation system (sTs). The sTs used solidrocket boosters and three main engines to launchthe shuttle orbiter. The reusable boosters fell offabout two minutes into the flight. Parachutes de-

Skylab in orbit over the

Amazon River in Brazil

Neil Armstrong's photo of Buzz Aldren

planting the U.S. Flag on the Moon

8

ployed to decelerate the solid rocket boosters for a safesplashdown in the Atlantic Ocean, where ships recoveredthem. The sTs, commonly referred to as the Space Shuttle,

was used for transportationto space and back to Earth.

This chapter gave abrief account of how rocketlaunch vehicles were usedin the space race. A moredetailed account of the Usmanned space program iscontained in module six ofAerospace Dimensions.

Rockets evolved fromsimple gunpowder devicesinto giant vehicles capableof traveling into outerspace, taking astronauts tothe moon and launchingsatellites to explore ouruniverse. Without a doubt,rockets have opened theuniverse to our explo-ration, and the possibilitiescontinue to be endless.

A space shuttle landing

Rocket timeline

A space shuttle launch

“

”

Activity One - The Hero EnginePurpose: The purpose of this activity is to demonstrate Newton’s Third Law of motion, which was discussed in this chapter as related to the Hero Engine.

Materials: empty soda can, medium-size nail, string, bucket or tub of water, and a hammer

Procedure: 1. Lay the can on its side and carefully punch four equally-spaced holes in the can.

Before removing the nail, push the nail to the right so that the hole is slanted in that direction. The holes should be just above the bottom rim. (Adult supervisionsuggested.)

2. Bend the opener at the top of the soda can straight up and tie a short piece of stringto it.

3. Immerse the can in the water until the can is full.4. Pull the can out of the water by the string. Water will stream out of the openings

causing the can to spin.

Summary: This replicates the very first rocket engine, the Hero Engine. Although the Hero Enginewas propelled by steam, this activity demonstrates thrust and Newton’s Third Law of motion. New-ton’s Third Law of motion states that for every action there is an equal and opposite reaction. Theforce of falling water at slanted intervals around the can (action) causes the soda can to spin in the op-posite direction (reaction).

Activity Two - Making a Paper RocketPurpose: The purpose of this activity is to create a paper rocket and experiment with the flight of thepaper rocket as pushed through a tube, as discussed in this chapter about early rockets. The use of fins willaid with stabilization of the rocket, as also discussed in the chapter.

Materials: paper, cellophane tape, scissors, sharpened pencil, and a straw (slightly thinner than the pencil)

Procedure: 1. Cut a piece of paper 1.5

inches wide by 1 inchshorter than the straw tobe used.

2. Wrap the paper aroundthe pencil.

3. Tape tube in three placesas shown.

4. Remove pencil and cutoff ends of tube.

5. Reinsert pencil into tube and tape around sharpened point of the pencil.6. Cut out fins in any shape you like and tape to base of rocket.7. Remove the pencil from tube. Insert the straw into the open end of the paper rocket.

11

Step StepStep

Step Steps

Step

Step

Cuthere

Foldline

TapeTape

Tape

9

10

8. Launch the rocket by blowing on the end of the straw.

Summary: Paper rockets demonstrate how rockets fly through the air and the importance of havingfins for control. When experimenting with the flight of the rocket, the more the force of air applied tothe paper rocket, the farther it soars. Also, launching the rocket at different angles results in differentheights and distances that the rocket achieves. Consider experimenting with the placement of fins andnumber of fins. Having no fins at all results in an unstable rocket!

Activity Three - Rocket StagingPurpose: In this activity, the concept of how rocket stages work is visually demonstrated using balloons.

Materials: two long party balloons, nylon monofilament fishing line (any weight), two plastic straws(milkshake size), styrofoam coffee cup, masking tape, scissors, and two spring clothespins

Procedure: 1. Thread the fishing line through the two straws. stretch the fishing line snugly across a room and

secure its ends to stable areas, such as a cabinet or wall. make sure the line is just high enough forpeople to pass safely underneath.

2. Cut the coffee cup in half so that the lip of the cup forms a continuous ring.3. stretch the balloons by pre-inflating them. Inflate the first balloon about three-fourths full of air and

squeeze its nozzle tight. Pull the nozzle through the ring. Twist the nozzle and hold it shut with aspring clothespin. Inflate the second balloon. While doing so, make sure the front end of the secondballoon extends through the ring a short distance. As the second balloon inflates, it will pressagainst the nozzle of the first balloon and take over the clip's job of holding it shut. It may take a bitof practice to achieve this. Clip the nozzle of the second balloon shut also with the clothes pin oryour fingers.

4. Take the straws to one end of the fishing line and tape each balloon to a straw with masking tape.The balloons should point parallel to the fishing line.

5. Remove the clip from the first balloon and untwist the nozzle. Remove the nozzle from the secondballoon as well, but continue holding it shut with your fingers.

6. If you wish, do a rocket countdown as you release the balloon you are holding. The escaping gaswill propel both balloons along the fishing line. When the first balloon released runs out of air, itwill release the other balloon to continue the trip along the line.

7. Have students experiment with other ways to make multi-stage rockets work. Add 2, 3, or 4 stages,as is possible.

Summary: This activ-ity demonstrateshow a multi-stagerocket works.After a stage ex-hausts its load ofpropellants, theentire stage dropsaway, making theupper stages moreefficient in reach-ing higher alti-tudes.

Learning Outcomes

- Define acceleration.- Define inertia.- Define thrust.- Describe Newton's First Law of motion.- Describe Newton's second Law of motion.- Describe Newton's Third Law of motion.- Identify the four major systems of a rocket.- Describe the purpose of each of the four major systems of a rocket.- Define payload.- Describe how the world land speed record applies to rockets.

Important Terms

acceleration - the rate of change in velocity with respect to time

airframe - provides the shape of the rocket, within which all of the other systems are contained

control system - steers the rocket and keeps it stable

guidance system - gets the rocket to its destination; the brain of the rocket

inertia - the tendency of an object at rest to stay at rest and an object in motion to stay in motion

Newton's First Law of Motion - a body at rest remains at rest and a body in motion tends to stay inmotion at a constant velocity unless acted on by an outside force; inertia

Newton's Second Law of Motion - the rate of change in the momentum of a body is proportional tothe force acting upon the body and is in the direction of the force

Newton's Third Law of Motion - for every action there is an equal and opposite reaction

payload - what the rocket is carrying

propulsion - everything associated with propelling the rocket

thrust - to force or push; the amount of push used to get a rocket traveling upwards

In this chapter, we will take a brief look at some of the concepts and principles that explain howrockets work, with a particular emphasis on Newton's Laws of motion. These laws lay the scientificfoundation for rockets and aid tremendously in explaining how rockets work.

PRINCIPLESIn its simplest form, a rocket is a chamber enclosing a gas under pres-

sure. A small opening at one end of the chamber allows the gas to escape,and thus provides a thrust that propels the rocket in the opposite direction.A good example is a balloon.

Balloons and rockets actually have a strong similarity. The only signifi-cant difference is the way the pressurized gas is produced. With spacerockets, the solid or liquid burning propellants produce the gas.

AIR MOVES BALLOON MOVES

22

11

12

NEWTON'S LAWS OF MOTIONEven though rockets have been around for over 2,000 years, it has only been in the last 300 years

that rocket experimenters have had a scientific basis for understanding how they work. This scien-tific basis came from sir Isaac Newton. Newton stated three important scientific principles that gov-ern the motion of all objects, whether on Earth or in space. Understanding these principles hasenabled rocketeers to construct the giant rockets we use today. These principles are known as New-

ton's Laws of Motion.

Newton's First Law of Motion: a body at rest remains at rest and a body in motion tends to stay

in motion at a constant velocity unless acted on by an outside, or unbalanced, force.

Rest and motion are the opposite of each other. If a ball is sitting on the ground, it is at rest. If it isrolling, it is in motion. If you hold a ball in your hand and keep it still, the ball is at rest. All the timethe ball is being held there, it is acted upon by forces. The force of gravity is trying to pull the balldownward, while at the same time your hand is pushing against the ball to hold it up. The forces act-ing on the ball are balanced. Let the ball go, or move your hand upward, and the forces become un-balanced. The ball then changes from a state of rest to a state of motion.

In rocket flight, forces become balanced and unbalanced all the time. A rocket on the launch padis balanced. The surface of the pad pushes the rocket up while gravity tries to pull it down. As theengines are ignited, the thrust from the rocket unbalances the forces, and the rocket travels upward.Thrust is defined as the amount of push used to get the rocket traveling upwards.

Consider a grocery cart full of groceries that you are pushing down an aisle. Let's pretend there isno friction from the wheels or from the floor. The cart weighs 75 pounds and you are pushing it at100 ft/min. What force must you exert on the cart to keep it moving in a straight line at this constantspeed? The answer is none. You exerted a force to start it from rest, and you will need to exert aforce to stop it, but no force is needed to keep it moving at constant velocity if there is no friction.Inertia is the tendency of an object at rest to stay at rest and an object in motion to stay in motion.(see associated Activity Four at the end of the chapter.)

Newton's Second Law of Motion: the

rate of change in the momentum of a

body is proportional to the force acting

upon the body and is in the direction of

the force.

This law is essentially a mathematicalequation. There are three parts: mass (m),acceleration (a), and force (f) so that f =ma (force equals mass times accelera-tion). The amount of force required to accelerate a body depends on the mass of the body. The moremass, the more force is required to accelerate it.

Acceleration is defined as the rate of change in velocity with respect to time. Use a cannon as anexample to help explain. When the cannon is fired, an explosion propels a cannon ball out the openend of the barrel. It flies to its target. At the same time, the cannon itself is pushed backward. Theforce acting on the cannon and the ball is the same. since f = ma, if the mass increases, then the ac-celeration decreases; if the mass decreases, then the acceleration increases.

Apply this principle to a rocket. Replace the mass of the cannon ball with the mass of the gasesbeing ejected out of the rocket engine. Replace the mass of the cannon with the mass of the rocketmoving in the other direction. Force is the pressure created by the controlled explosion taking place

AA MF

ROCKET SYSTEMSmodern rockets consist of four major systems: air-

frame, guidance, control, and propulsion. These four sys-tems work together to deliver the payload. The payload isdefined as whatever the rocket is carrying. For instance,the payload of a military rocket might be explosives, whilethe payload of a civilian rocket might be satellites. The as-tronauts and their data are also part of the payload.

The airframe provides the shape of the rocket and allof the other systems are contained within it. The airframemust be light-weight, yet structurally strong. It must with-stand heat, stress, and a lot of vibration. The primary ob-jective in the design and construction of an airframe is tobuild a structure that will withstand all anticipated stresseswhile using the least possible weight. For example, theairframe of the Atlas rocket is thinner than a dime. Whenthe Atlas has no fuel aboard, it must be pressurized tokeep it from collapsing. The airframe is the skin of therocket and serves as the wall of the propellant tanks.This eliminates the need for separate internal tanks andsaves in weight, too.

The guidance system is the "brain" of a rocket. It isresponsible for getting the rocket and its payload to itsdestination. In a military missile, the guidance systemdelivers the warhead to its target. In a civilian rocket, theguidance system is responsible for delivering the space-craft to its proper orbit or destination.

The guidance system is small compared to the rest ofthe rocket. This photo on the right gives you an idea ofits actual size. It is a self-contained electronic unit with a

Air-frame

Person or Equipment Payload

GuidanceSystem

ControlSystemPropellant

PropulsionSystem

Major Systems of Rockets

The Guidance System

inside the rocket's engines. That pressure accelerates the gas one way and the rocket the other.Another example of this law would be a hockey puck sliding over the ice. That puck has a quan-

tity of motion that slowly decreases due to being in contact with the ice, which causes friction.

Newton's Third Law of Motion: for every action, there is an equal and opposite reaction.

A rocket can lift off from a launch pad only when it expels gas out of its engine. The rocketpushes on the gas, and the gas in turn pushes on the rocket. The example of a skateboard and rider il-lustrates this point. Imagine the skateboard and rider at rest. The rider jumps off the skateboard. Thejumping is called the action. The skateboard responds to that action by traveling some distance in theopposite direction. The skateboard's opposite motion is called the reaction. Another example is aman walking on level ground pushes against the ground with his feet. The earth also pushes againsthis feet with an equal and opposite force.

With rockets, the action is the expelling of gas out of the engine. The reaction is the movement ofthe rocket in the opposite direction. To enable a rocket to lift off from the launch pad, the action, orthrust, from the engine must be greater than the weight of the rocket. (see associated Activity Five,six, and seven at the end of the chapter.)

13

14

computer. The computer is programmed to guide therocket on a desired trajectory. There is also a radio linkbetween the rocket's mission controllers and its guidancesystem. This allows changes to be made if necessary.

The control system takes the information from theguidance system and steers the rocket to its destination.The control system also keeps the rocket stable. The con-trol system is actually several controls that work to stabi-lize and steer the rocket. These controls allow forchanges to be made during the rocket's flight.

Vanes, movable fins, gimbaled nozzles, and attitude-control rockets are a few examples of controls that canhelp steer or stabilize a rocket. Vanes are like small finsthat are placed inside the exhaust of the rocket engine.Tilting the vanes deflects the exhaust and changes the di-rection the rocket is going. A gimbaled nozzle is one thatsways while the exhaust passes through it. This alsochanges a rocket's direction. A rocket’s movable fins canbe tilted to change the rocket's direction, as well. Themost commonly used control system is the attitude-control rockets. small clusters of engines are mounted allaround the vehicle. By firing the right combination ofthese small rockets, the vehicle can be turned in any di-rection.

The propulsion system consists of everything directlyassociated with propelling the rocket. This includes thepropellant used, the containers for the propellant, and theengine. The propellant doesn't mean just the fuel, but in-cludes both the fuel and the oxidizer. The fuel is thechemical the rocket burns and the oxidizer (oxygen) mustbe present. Rockets must carry oxygen with them be-cause there is none in space.

There are two rocket propellants, liquid and solid.solid rocket propellants were used for 700 years beforethe liquid propellant was created. The solid propellant iscarried in the combustion chamber and is much simplerthan the liquid propellant. The solid propellant is illus-trated in the picture on the right. The fuel is usually amixture of hydrogen compounds and carbon, and the oxi-dizer is made up of oxygen compounds.

The liquid propellant is much more complicated. Liquid propellants are carried in compartments separatefrom the combustion chamber, one for the fuel and one forthe oxidizer. The liquid propellant is usually kerosene or liq-uid hydrogen; the oxidizer is usually liquid oxygen.

The liquid propellant is what is commonly used today. It is heavier than a solid propellant, buteasier to control. (see associated Activity Eight at the end of the chapter.)

Fins

Injectors

Pumps

Fuel

Oxidizer

Payload

CombustionChamber

Nozzle

Payload

Igniter

Casing(Body tube)

Core

Fins

ThroatNozzle

Propellant (Grain)

CombustionChamber

Solid Fuel Propulsion System

Liquid Fuel Propulsion System

THE ROCKET ENGINE AND THE WORLD LAND SPEED RECORDA rocket can operate in space, where there is almost no air. A rocket can produce more power for

its size than any other kind of engine. For example, the main rocket engine of the space shuttle

weighs only a fraction as much as a train engine, but it would take 39 train engines to produce the

same amount of power. When that enormous power is applied to a car, speeds in excess of 1000

miles per hour are possible. more and more rockets are going to be used along with jet engines to

make cars go faster. (see associated Activities Nine and Ten at the end of the chapter.)

Gary Gabelich was

the driver of a car called

the “Blue Flame” that set

the land speed record on

October 28, 1970. The

car was rocket-powered

and reached a speed of

622.407 miles per hour.

The car was almost 42

feet long, weighed 7,700

pounds, and had a height

at the fin of 7’6”. Its fuel

was pressure fed

methane and the oxidizer

was hydrogen peroxide.

It had a thrust power of close to 50,000 pounds.

In the following section you will learn that the

sound barrier was broken on land in a car, featured

here, called the Thrust ssC. Although not rocket

powered, but jet-engined powered, high interest and

commonalities in thrust power led to inclusion in

this chapter.

The Blue Flame was a rocket-powered car that exceeded

600 miles per hour. Image courtesy of the Viper Club

This illustration clearly shows how the oxidizer and

fuel can be self-contained. In an aerospace craft or

an automobile, an enormous amount of power can

be made available. Image courtesy of NASA Thrust SSC

15

16

The British Hold The Record For the World’s Fastest Car

Back in 1997, a British team was the first to break the sound barrier on land in a jet-powered car.

The team was put together by Richard Noble, who directed a project that built and ran an incredible

car called the Thrust ssC. He is also a previous land-speed record holder.

Thrust ssC (super sonic Car) is a British-designed and built project. The leadership in the team

effort included Noble, Glynne Bowsher, and Jeremy Bliss. The driver was Andy Green (a Royal Air

Force pilot who flies the famous Tornado aircraft).

On October 15, 1997, Green piloted the most powerful, most extraordinary car ever to be de-

signed to attack the Land speed Record to a speed of 763 miles per hour (1,228 km/hour) to offi-

cially break the sound barrier on land. There was an earlier claim that an American rocket car, called

the Budweiser Rocket, broke the sound barrier. That controversy is still being resolved.

The Thrust ssC car broke the official record on

the Black Rock Desert in Nevada. It was powered by

two Rolls Royce spey Turbofan engines from an

American mcDonnell F-4 Phantom fighter and was

equipped with afterburners. The two engines devel-

oped a combined thrust of 50,000 pounds or approxi-

mately 110,000 horsepower. During the “run for the

record,” the engines burned an incredible 4.8 gallons

per second of fuel. The official records show that the

car achieved the following speeds:

• Flying mile 1227.986 km/h (763.035 mph)

• Flying kilometer 1223.657 km/h (760.343 mph)

This is a cutaway illustration, by Lawrence

Watts and the Castrol Corporation, that shows the

components of the Thrust SSC. It is 16.5 m (54 ft)

long, 3.7 m (12 ft) wide, and weighs 10.5 tons.

Image courtesy of Richard Noble

Royal Air Force pilot, Andy Green, was also the

pilot of the SSC and holds the record as being the

“Fastest Man Alive on Earth.”

THE UNITED STATES AND CANADA TAKE THE CHALLENGEAn American and Canadian team have joined together to bring the world land speed record back

to North America. It is called the North American Eagle Land speed Program. The challenge is tomake the transition from subsonic to supersonic speed and break the current land speed record of763 miles per hour. The team is using a modified F-104 starfighter that will make the runs. Al-though, again, not rocket powered, but jet-engine powered, this information is included for interestand close alignment to the principles of rocket propulsion.

Former record

holder and Thrust

SSC Director,

Richard Noble

Image courtesy of

Richard Noble

The Thrust SSC after its monumental run of 763 miles per hour — fifty years almost to the day after Chuck

Yeager broke the sound barrier in the skies over what is now Edwards Air Force Base, CA

At speed, the Thrust SSC is going 1100 feet per second

17

18

What are the Expected Results?Edward shadle and co-Director Keith Zanghi had this to say about the effort and its impact on

mankind: “Few people on this earth have ventured into the realm of such high speeds on the surfaceof this earth. Researchers today may not be able to explain what phenomenon occurs as a vehicle tran-sitions past the speed of sound and what happens beyond that speed, but that's because man has notbeen able to go there, until now. We want to know, and we want to share that information. many ques-tions beg to be answered about this issue. What bearings can handle the weight loading and revolu-tions per minute in these high-speeds? Can the aluminum-alloy wheels withstand the tremendouscentrifugal force? What about the shock wave and acoustical absorption of it into the earth's surface?Can we keep this beast controlled and stopped safely? To the average individual, these issues may notseem worth bothering to learn about. However, most people who had a difficult time envisioning thebenefits from the space race program of NAsA in the '60s, are now taking those benefits for granted;microwave ovens, VCR and DVD players, cellular phones, and the computer to name a few. Theknowledge gained can have more far-reaching impact than would appear at first. This has usuallybeen the case with research that seems initially frivolous.” (To keep up with the progress of the NorthAmerican Eagle program, and the benefits to future aerodynamic progress, go towww.landspeed.com)

NEXT STEP, PROJECT BLOODHOUND – A ROCKET POWEREDCAR THAT WILL BREAK 1000 MILES PER HOUR ON THE GROUND

BLOODHOUND ssC (super sonic Car) has gone through ten design evolutions since workstarted. The original plan had been to position the small 200 kg rocket above the heavier 1,000 kgEJ200 Eurofighter Typhoon jet engine and the car was designed accordingly over the following 18months.

The United States and Canada are making a joint effort to be the fastest car on Earth.

This is the North American Eagle. Image Courtesy of the North American Eagle Land Speed Program

As the project developed it became clear that more thrust was required to overcome the aerody-namic drag. This culminated in a hybrid rocket weighing 400 kg. The extra thrust also created a freshchallenge for the engineering team: The rocket firing would violently pitch the car nose-down, desta-bilizing the whole vehicle.

The engineering team lead by John Piper, engineering director, began a radical re-design of thecar which saw the jet engine positioned over the rocket. This re-design was made possible by partnerIntel providing one of the largest computer clusters in the country. Designs are tested using Compu-tational Fluid Dynamics (CFD) technology developed at swansea University. Tests that previouslytook one day to be run could now be completed in just a couple of hours with the increase in com-puting resource provided by Intel.

Wheel designLockheed martin UK has been developing the BLOODHOUND ssC wheel design to ensure they

can withstand forces of 50,000 radial g at the rim and support a 6.5 ton car travelling at 1,050 mph.Research by Lockheed martin UK has focused on a 90 cm diameter wheel design, constructed fromforged aerospace-grade aluminum.

Rocket test programBLOODHOUND ssC will feature the largest hybrid rocket ever designed in the United King-

dom. The rocket weighs in at 400 kg, it is 45 cm (18 inches) in diameter and, at 425 cm (14 feet)long, is the same length as a Formula One car. The rocket is designed to produce 27,500 lbs ofthrust. Together with BLOODHOUND ssCs EJ200 jet engine (20 000 lb thrust), this will give thecar a total of 212 kN (47,500 lb) of thrust – the equivalent of 135,000 HP, or the power of 180 For-mula One cars.

World Land Speed Record run siteThe BLOODHOUND team scoured the globe looking for the perfect run location on which to

make their attempt on the World Land speed Record.The site needed to fulfill some very specificcriteria: It had to be 10 miles long, have one mile of clear run off at each end, be dead flat, and befirm enough to support a 6.5 ton car moving at 1,000 mph. The search began with a computer pro-gram that utilized space shuttle radar survey data and satellite imagery to identify potential loca-tions. It produced several thousand possibilities, which were then whittled down using Google Earth.Following a rigorous process of elimination, the short list contained some 35 deserts and salt flats,including: Bonneville salt Flats and the Black Rock desert, UsA; Lake Tuz, Turkey; Verneuk Pan,south Africa plus Lake Gairdner and Lake Eyre, Australia.

Andy Green, driver of BLOODHOUND ssC, visited the majority of these deserts to conduct on-

19

Bloodhound SSC

20

site surveys in order to identify the location best suited to a record-breaking run. Verneuk Pan in theNorthern cape of south Africa came out on top. Verneuk Pan is the site of malcolm Campbell’s ill-fated bid for the World Land speed Record in 1929, which is 830 m above sea level. With his engineperformance limited by the thin air, Campbell only managed 218.5 mph.

A thorough survey conducted at Verneuk Pan found it wasn’t practical to clear the stone-litteredsurface. However, a previously discounted desert lying 400 km north was identified as a possible runsite. A more detailed survey found the ideal location: Hakskeen Pan, Northern Cape province, southAfrica. Hakskeen Pan offers a 12 mile-long track across a perfectly flat dried-up lake bed. The sur-face is relatively free from debris and stones but it is crossed by a dirt track which will need to be re-moved prior to record-breaking runs in 2011. The Project has received fantastic support from theNorthern Cape Government, which has undertaken to prepare Hakskeen Pan for the World Landspeed Record runs as part of the Northern Cape’s development as a world-class adventure sports lo-cation.

SponsorsThe Project currently has 166 product sponsors supporting it. These range from specialist product

suppliers such as Goodridge Hoses to multinationals such as, Lockheed martin and IT partner, Intel.many of these companies have borne the brunt of the recession, but have come onboard to sup-

port this groundbreaking education program as they see first-hand that their industries have a realneed for more skilled engineers, mathematicians, and scientists. This has become a great challenge toproduce the next generation of aerospace and aerodynamic scientists, engineers, and mathematicians.The excitement of such endeavors is hoped to inspire students toward more sTEm-related careerchoices.

Bloodhound SSC

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Activity Five - 3-2-1 POPPurpose: This activity helps explain how thrust is generated in a rocket. It alsodemonstrates Newton’s Third Law of motion.

Materials: heavy paper (60-110 index stock or construction paper), plastic 35mm canister with lid on inside of canister (or equivalent), student sheets, cello-phane tape, scissors, effervescing antacid tablet, paper towels, water, and eyeprotection (Note: In the past, Fuji film canisters were free and easy to locate.Due to digital photography this is no longer the case. A good source to locatefilm canisters is Educational Innovations @ www.teachersource.com Item #CAN-300 12@$7.95.)

Procedure:

1. Wrap and tape a tube of paper around the film canister. The lid end of thecanister goes down.

Activity Four - Law of Inertia (Newton’s First Law)

Purpose: The purpose of this activity is to demonstrate New-ton’s First Law of motion, the law of inertia.Material: stack of checkers, ball Procedure:1. stack the checkers, leaving one out for step #2.2. shoot the extra checker so it hits the bottomchecker. When you shoot the checker, you are introduc-ing an outside force to the stack of checkers. When ithits the bottom checker, its inertia is transferred and the bottom checker moves with almost the samespeed and inertia.3. Next, you can take a ball and cup it in your hand, like the picture to the right. It is in a state of rest.Gravity is pushing down on the ball, while your hand is pushing up. If you remove your hand, theball drops and is in a state of motion. It stayed at rest until an unbalanced force, gravity, makes itmove downward.Summary: Newton’s First Law of motion explains that an object at rest remains at rest and a body inmotion tends to stay in motion at a constant velocity unless acted on by an outside force. Energy istransferred from the moving checker (the outside force) to the checker at the bottom of the stack (objectat rest), resulting in the bottom checker being moved. Depending on the surface of the table or floorbeing used, 100% of the energy will not be transferred to the other checker due to friction. Friction isthe force of two objects in contact that results in the slowing or stopping of an object. A smooth surfaceresults in less friction. A rougher surface, such as carpet, creates more friction. A rocket cannot launchuntil a force acts upon it resulting in its launch. As the rocket travels through the atmosphere, atmos-pheric drag (fluid friction) works against the upward motion of the rocket.

BALL AT REST

GRAVITY

LIFT

Activity Six - Two Balloons (Newton’s Third Law)

Purpose: This activity demonstrates Newton’s Third Law of motion.

Materials: two balloons, inflated and tied

Procedure: 1. squeeze the two balloons together, pushing with only one of them.

The pusher is compressed by the force of the push. The pushed isalso compressed from pushing back with equal force.

2. To prove further that they are pushing on each other equally, let go all atonce. The balloons spring back into shape and push each other apart.

Summary: In this demonstration, only one balloon is doing the pushing,but the other balloon is pushing back at an equal and opposite force. Whenthe balloons are released, they push apart equal distances.

PUSHEDPUSHER

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4

LidCone Pattern(Cone can be

any size)Overlap this edge to form

cone

Tape

Countdown: 5. Turn the rocket upside down and fill the canister one-third full of water.Work quickly on these next steps!6. Drop in 1/2 of the antacid tablet.7. snap lid on tight.8. Turn rocket right-side up and set on ground.9. stand back.

10. LIFT OFF!

Summary: Once the fizzy tablet reacts with the water in the film canister,gas bubbles are produced. much pressure is produced by the gas buildingup inside the canister. Unlike a balloon, the canister cannot expand as theamount of gas being produced increases. Eventually, so much gas pressureis produced that it forces the canister to pop open. The gas rushing down-ward out of the canister causes the rocket to move upward, demonstratingNewton’s third law of motion. Real rockets work in a similar way; how-ever, they use real rocket fuel.

2. Tape fins to your rocket.3. Roll a cone of paper and tape it to the rocket's upper end.4. Ready for flight.

Activity Seven - Roller Skates and Jug (Newton’s Third Law)

Purpose: This activity demonstrates Newton’s Third Law of motion.

Material: roller skates and plastic jug of water

Procedure:Wearing roller skates, with feet parallel, throw a plastic jug of water to a friend 10 feet away(as you push forward, you roll backward). OR, use a skateboard to demonstrate the same thing.stand on a skateboard with the board not moving. Then jump off the board. Your jumping off is theaction, and the board moving in the opposite direction is the reaction.

Summary: Newton’s Third Law of motion states that for every action, there is an equal and oppo-site reaction. Throwing the jug forward (action) results in the person with the skates or skateboard tomove in the opposite direction (reaction). This action parallels the hot gases from the burning fuelthat rush out of the rocket (action) results in the rocket moving in the opposite direction (reaction).

ACTIONREACTION

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Activity Eight - Antacid Tablet Race - Experiment 1Purpose: Use scientific investigation skills to compare the reaction rates of effervescent antacid tabletsunder different conditions, in alignment with the discussion of liquid propellants in the chapter.

Materials: effervescent antacid tablets (4 per group), two Beakers (or glassor plastic jars), tweezers or forceps, scrap paper, watch or clock with secondhand, thermometer, eye protection, and water (warm and cold)

Procedure: Experiment 1

1. Fill both jars half full with water that is the same temperature.2. Put on your eye protection.3. Predict how long it will take for the tablet to dissolve in the water. Drop a

tablet in the first jar. shade in the stop watch face for the actual number ofminutes and seconds it took to complete the reaction. The stopwatch canmeasure 6 minutes.

Jar 1 Results Jar 2 Results

Temperature: _____ Temperature: _____Your prediction: _____ seconds Your prediction: _____ seconds

Procedure: Experiment 2

1. Empty the jars from the first experiment. Put warm water in one jar and cold in the other.2. measure the temperature of the first jar. Predict how long it will take for a tablet to dissolve. Drop

a tablet in the jar. shade in the clock face for the actual number of minutes and seconds it took tocomplete the reaction.

3. measure the temperature of the second jar. Predict how long it will take for a tablet to dissolve inthe water. Drop a tablet in the jar. shade in the clock face for the actual number of minutes andseconds it took to complete the reaction.

0 15

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30

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Jar 1 Results Jar 2 Results

Temperature: _____ Temperature: _____Your prediction: _____ seconds Your prediction: _____ seconds

Describe what happened in the experiment and why.How can you apply the results from these experiments to improve rocket performance?Summary: The amount of surface area of the tablet and the temperature of the water will affect thereaction of the tablets. This activity relates to increasing the power of rocket fuels by manipulatingsurface area and temperature. When rocket propellants burn faster, the mass of exhaust gases ex-pelled increases, as well as the speed at which those gases accelerate out of the rocket nozzle. Basedon Newton’s second Law of motion, increasing the efficiency of rocket fuels increases the perform-ance of the rocket. Expanding the burning surface increases its burning rate. This increases theamount of gas (mass) and acceleration of the gas as it leaves the rocket engine.

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Activity Nine - Rocket RacerPurpose: Experiment with force and Newton’s Laws of motion in this activity.

Materials: four straight pins, styrofoam meat tray, masking tape, flexible straw, scissors, drawingcompass, marker pen, small round party balloon, ruler, and student sheets (one set per group); 10-meter tape measure or other measuring markers for track (one for whole class)

Procedure:1. Distribute the materials and construction tools to each group. If you are

going to construct a second racer, save the styrofoam tray scraps for later.Hold back the additional materials for the second racer until you need them.

2. Build racer, as per directions below.(Note) You should plan the arrangement of parts on the tray before cuttingthem out. If you do not wish to use scissors, you can trace the pattern pieceswith the sharp point of a pencil or a pen. The pieces will snap out of the styro-foam if the lines are pressed quickly.

3. Lay out a track on the floor approximately 10 meters long, (or about 33 feet). severalmetric tape measures joined together can be placed on the floor for determining how far the racerstravel. Distances should be measured in 10 centimeter intervals.

4. Distance data sheets and a drawing of constructed racer should be prepared to record test runs andactual runs of races.

5. Test racers as they are completed. Fill in the data sheets and create a report cover with a drawingof the racer they constructed.

6. If a second racer will be constructed, distribute design pages before starting construction.

Build Racer:1.Design a pattern to fit on the styroform tray. You need one car body, four wheels, and four hub-

caps. Use a compass to draw the wheels. Lay out your pattern on the tray and then cut them out. 2. Blow up the balloon and let the air out. Tape the balloon to the short end of a flexible straw and

then tape the straw to the rectangle.3. Push pins through the hubcaps into the wheels and then into the edges of the rectangle.4. Blow up the balloon through the straw. squeeze the end of the straw. Place the racer on the floor

and let it go.

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Activity Ten - Newton CarPurpose: Experiment with a slingshot-like device that throws a film canister filled with various ob-jects, and demonstrate Newton’s Laws of motion.

Materials: wooden block about 10x20x2.5 cm (about 4x8x1 inch), 3 3-inch #10wood screws (round head), 12 round pencils or short lengths of similar dow-els, plastic film canister or equivalent, assorted materials for filling can-ister (washers, nuts, etc.), 3 rubber bands, cotton string, matches orlighter, eye protection for each student, metric beam balance(primer balance), vice, screwdriver, and a meter or measuringstick or device

Procedure:1. Tie six string loops the size shown here. 2. Fill up your film canister and weigh it in grams. Record the mass in the

Newton Car Report Chart.3. set up your Newton Car as shown in the picture. slip the rubber band through the string loop.

stretch the rubber band over the two screws and pull the string back over the third screw. Placethe rods 6 centimeters (about 2.5 inches) apart. Use only one rubber band the first time.

4. Put on your eye protection!5. Light the string and stand back. Record the distance the car traveled on the chart.6. Reset the car and rods. make sure the rods are the same distance apart. Use two rubber bands.

Record the distance the car travels.7. Reset the car with three rubber bands. Record the distance it travels.8. Refill the canister and record its new mass.9. Test the car with the new canister mass and with one, two and three rubber bands. Record the dis-

tances the car moves each time.10. Plot your results on the graph. Use one line for the first set of measurements and a different line

for the second set.Summary: Besides demonstrating Newton’s First and Third Laws of motion, this activity is an ex-cellent tool for investigating Newton’s second Law of motion, which states that force equals masstimes acceleration. manipulating different variables, such as the size of the string loop and the place-ment of the mass on the car, influences the results. By experimenting with a number of variables ona rocket, scientists can design a rocket that flies according to the purpose for which it was designed.

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CAR BODY HUBCAPS

WHEELS

Summary: This activity demonstrates Newton’s Laws of motion. The rocket racer stays at rest unlessthe force of air released from the balloon causes it to move forward. It will continue moving forwarduntil the air is exhausted from the balloon. (1st law) The more air that is placed in the balloon, thefarther the rocket racer travels. (2nd law) Air rushing out of the end of the racers causes the racer tomove forward. (3rd law)

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Describe what happened when you tested the car with one, two, and three rubber bands._________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Mass 2______Grams

Mass 1______Grams

RUBBER BANDS DISTANCE TRAVELED

RUBBER BANDS DISTANCE TRAVELED

1

1

2

2

3

3Describe what happened when you tested the car with one, two, and three rubber bands.__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Write a short statement explaining the relationship between the amount of mass in the canister, the number of rubber bands, and the distance the car traveled.

__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Newton Car Report:Team Members:_____________________________________ _______________________________________ _____________________________________ _______________________________________ _____________________________________ _______________________________________

3

2

1

0

Numb

er of

Rub

ber B

ands

50 100Distance in Centimeters

150 200

SAMPLE

Mass 1= _______grams (weight)Mass 2= _______grams (weight)

Learning Outcomes- Describe the requirements for achieving the X-Prize. - Describe SpaceShipOne’s achievements.- Describe the future flight sequence of SpaceShipTwo.

Important Terms SpaceShipOne – aircraft with suborbital capabilitySpaceShipTwo – SpaceShipOne’s successor that could possibly offer the general public space travel

ROCKETS IN THE SECOND MILLENIUMIn 1995, Dr. Peter H. Diamandis conceived an award, which he called the “Ansari X-Prize” that

would encourage PRIVATE space flight. The requirements were that a non-government-supportedaerospace craft would have to fly to an altitude of 100 km or 62 miles above the surface of the Earthand return safely. Then, within a period of 2 weeks, the same flight would have to be repeated. Onboth occasions, the vehicle was required to carry the weight of three adult humans. For this accom-plishment, a prize of $10,000,000 would be awarded.

The organizers of the Ansari X-Prize, together with the scientific community, set the altitude of 62miles, or 100 kilometers, as the line that defines the beginning of space. Twenty-six teams from 7countries competed for the prize and many attempts to win it were made over a period of 8 years.

On June 21, 2004, mike melvill, test pilot for scaled Composites of mojave Aerospace Ventures,flew their entry for the competition, SpaceShipOne, ona record-breaking flight. melvill reached an altitude of328,491 feet, making him the first private pilot to earnNAsA’s highly-coveted astronaut wings.

Three months later, on september 29, melvill flewSpaceShipOne again on the first official mission tomeet the requirements set forth in the rules of compe-tition for the X-Prize. He accomplished all competi-tion requirements on that flight. Then, on October 4,another test pilot for scaled Composites, Brian Binnie,flew the vehicle to an altitude of 347,442 feet, or 69.2miles to win the prize. That flight marked the 47th an-niversary of the soviet Union’s launch of Sputnik.

On November 6, 2004, scaled Composites wasawarded the $10m prize. since that time, more than$1.3B has been invested world-wide in a new industry… private space travel.

Test flight crew of SpaceShipOne. From left to right,

top to bottom, Brian Binnie, Pete Siebold, Michael

Melvill, Douglas Shane. Photography by Bill Deaver.

Image courtesy of Aerospace Ventures LLC

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THE NEXT FRONTIER – PRIVATE SPACE TRAVELCommercial Airline-Type Space Travel –

Virgin Galactic

The first thing that comes to mind with theword “commercial” is, “how much does it costto go to space if you’re just a passenger and notan astronaut?” Initially, it will be $200,000 per

The aerospace “mother ship,” known as “White Knight” is shown here carrying

SpaceShipOne on a test flight. Image courtesy of Mojave Aerospace Ventures, LLC

Aeronautical engineer, Burt Rutan, is shown dis-

cussing the SpaceShipOne project with Microsoft’s

co-founder Paul G. Allen. Permission was given to

Civil Air Patrol by Aerospace Ventures, LLC. The flight profile of SpaceShipOne from release to land-

ing. Image courtesy of Mojave Aerospace Ventures, LLC

person. Virgin Galactic, a company that is a subsidiary of English-based Virgin Airlines and ownedby British billionaire sir Richard Branson, is building the first “airline to space.”

The success of SpaceShipOne prompted the businessman to explore the possibility of offering thegeneral public space transportation in a specially-built spacecraft known as SpaceShipTwo. Initially,the venture will take paying passengers on a sub-orbital flight to an altitude of 110 kilometers, or 68miles, into the thermosphere. SpaceShipTwo will reach 4,200 km/h (2,600 mph) using a single hy-brid rocket motor, which goes by the name RocketMotorTwo. During the flight, passengers will ex-perience a short period of weightlessness. The complete flight will take about 2.5 hours, with thefirst flights set to begin 2011.

From “ space bases” located near Upham, New mexico, and mojave, California, two crewmem-bers and six passengers will be taken aloft by the technologically-advanced “mother ship” known asWhite Knight Two. The first spaceliner that is taken aloft by White Knight Two, has been christenedVss (Virgin spaceship) Enterprise. This is a name given to honor the television and movie icon starTrek’s Enterprise.

In New mexico, there will be a 10,000 foot runway and a completely outfitted terminal facility forthe pioneering space passengers. The state of New mexico has invested close to $200 million dollarsin the project.

For their “ticket,” passengers will board the space craft for a series of safety briefings and then betaken to an altitude of 50,000 feet. SpaceShipTwo will then separate from the WhiteKnight II and berocketed into suborbital space. When the 110 km, or 68 mile, altitude is reached, passengers will beallowed to experience approximately 6 minutes of weightlessness. The passengers will be allowed torelease themselves from their seats and float around the cabin. The reason for this extended period ofweightlessness is the altitude reached is at the boundary of space. By going to 110 km, and a speedof mach 3, additional time in space can be realized.

SpaceShipOne after

its successful flight

with Mike Melvill as

the pilot.

Image Courtesy of

Mojave Aerospace

Ventures, LLC

SpaceShipOne Schematic

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During re-entry into the Earth’s atmosphere, Space-

ShipTwo will fold it’s wings upward and be gentlyslowed to prepare for a glide to landing at the spaceport.

sir Richard Branson unveiled the project on Decem-ber 7, 2009, at the mojave spaceport, the home base forBurt Rutan’s scaled Composite’s operation. Branson’scompany, Virgin Galactic, is part of an internationalconglomerate known as the Virgin Group. All of the ini-tial testing and marketing takes place in the United

WhiteKnight II and SpaceShipTwo in flight in preparation for launch – Image courtesy of Virgin Galactic

The first space base will be located in the State of New Mexico.

Sir Richard Branson and Burt Rutan showcase a model of the

WhiteKnight II and SpaceShipTwo for a press conference.

This illustration shows the difference between SpaceShipOne

and SpaceShipTwo in dimensions. Courtesy of Virgin Galactic

A test firing of the SpaceShipTwo rocket at the Mojave facility – Image courtesy of Virgin Galactic

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After a thrilling venture into space, Virgin Galactic’s

SpaceShipTwo prepares for re-entry and a slower speed

for landing. Image courtesy of Virgin Galactic

Flight profile of SpaceShipTwo

from release to landing

states; however, there are plans for other space facilitiesin England, scotland, sweden, and Dubai. Initial ordersare for two White Knight IIs and a fleet of five Space-

ShipTwos. The future also includes collaboration withNAsA for the possibility of launching low orbit satellites.This can be done at a greater savings of money thanusing extremely powerful, and extremely expensive con-ventional orbital rockets. The future of rocketry for con-tinued space travel and exploration is only beginning.The possibilities are limitless and all because of a sim-ple propulsion principle used in the exciting area ofrocketry! (see associated Activities Eleven, Twelve, andThirteen at the end of the chapter.)

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Activity Eleven - Bottle Rocket and Bottle Rocket Launcher Purpose: This activity demonstrates how a rocket works and Newton’s Laws of motion. It also pro-vides detailed, in-depth instructions to follow, much like the stringent rules governing the Arsari X-Prize!

Materials for Building Bottle Rocket: 2-liter plastic soft drink bottles, low-temperature glue guns,poster board, tape, modeling clay, scissors, safety glasses, decals, stickers, marker pens, launch padfor the bottle rocket launcher. Begin saving 2-liter bottles several days or weeks in advance so thatyou will have enough each participant. You also need a bottle rocket launcher to complete thisactivity. Instructions for building the launcher are below.

Procedure:1. Wrap and glue or tape a tube of poster board around the 2 liter bottle.2. Cut out several fins of any shape and glue them to the tube.3. Form a nose cone and hold it together with tape or glue.4. Press a ball of modeling clay into the top of the nose cone for weight.5. Glue or tape nose cone to upper end of bottle.6. Decorate your rocket.

Materials for Bottle Rocket Launcher: four 5" corner irons with 12 3/4" wood screws, one 5"mounting gate, two 6" spikes, two 10" spikes or metal tent stakes, two 5"x1/4" carriage bolts with 61/4” nuts, one 3" eyebolt with two nuts and washers, four 3/4" diameter washers to fit bolts, one #3rubber stopper with a single hole, one snap-in tubeless tire valve, wood board 12"x18"x3/4", a 2-literplastic bottle, electric drill and bits including a 3/8" bit, screw driver, pliers or open-end wrench to fitnuts, vice, 12' of 1/4" cord, a pencil, and a bicycle pump with psi measurement

Procedure:1. Prepare the rubber stopper by enlarging the hole with

a drill. Grip the stopper lightly with a vice and gentlyenlarge the hole with a 3/8" bit and electric drill. Therubber will stretch during cutting, making the finishedhole somewhat less than 3/8".

2. Remove the stopper from the vice and push the nee-dle valve end of the tire stem through the stopperfrom the narrow end to the wide end.

3. Prepare the mounting plate by drilling a 3/8" holethrough the center of the plate. Hold the plate with avice during drilling and put on eye protection. En-large the holes at the opposite ends of the plates, usinga drill bit slightly larger than the holes to do this. The holes must be large enough to pass the car-riage bolts through them. (see diagram)

4. Lay the mounting plate in the center of the wood base and mark the centers of the two outside holesthat you enlarged. Drill holes through the wood big enough to pass the carriage bolts through.

Hot G

lue

Wood Base

Attach BicyclePump Here

Mounting Plate

TireStemRubber Stopper

Nut

Nut

CarriageBolt

Washer

Attachment of Mounting Plate and Stopper

33

34

5. Push and twist the tire stem into the hole you drilled in the center of the mounting plate. The fatend of the stopper should rest on the plate.

6. Insert the carriage bolts through the wood base from the bottom up. Place a hex nut over each boltand tighten the nut so that the bolt head pulls into the wood.

7. screw a second nut over each bolt and spin it about half-way down the bolt. Place a washer overeach nut and then slip the mounting plate over the two bolts.

8. Press the neck of a 2-liter plastic bottle over the stopper. You will be using the bottle's wide necklip for measuring in the next step.

9. set up two corner irons so they look like bookends. Insert a spike through the top hole of eachiron. slide the irons near the bottle neck so that the spike rests immediately above the wide necklip. The spike will hold the bottle in place while you pump up the rocket. If the bottle is too low,adjust the nuts beneath the mounting plate on bothsides to raise it.

10. set up the other two corner irons as you did in theprevious step. Place them on the opposite side ofthe bottle. When you have the irons aligned so thatthe spikes rest above and hold the bottle lip, markthe centers of the holes on the wood base. For moreprecise screwing, drill small pilot holes for eachscrew and then screw the corner irons tightly to thebase on the opposite side of the bottle. When youhave the irons aligned so that the spikes rest aboveand hold the bottle lip, mark the centers of the holeson the wood base. For more precise screwing, drillsmall pilot holes for each screw and then screwthe corner irons tightly to the base.

11. Install an eye bolt to the edge of the oppositeholes for the hold-down spikes. Drill a hole andhold the bolt in place with washers and nuts ontop and bottom.

12. Attach the launch "pull cord" to the head end ofeach spike. Run the cord through the eye bolt.

13. make final adjustments to the launcher by at-taching the pump to the tire stem and pumpingup the bottle. Refer to the launching instruc-tions for safety notes. If the air seeps out aroundthe stopper, the stopper is too loose. Use a pairof pliers or a wrench to raise each side of themounting plate, in turn, to press the stopper withslightly more force to the bottle neck. When satisfied with the position, thread the remaining hexnuts over the mounting plate and tighten them to hold the plate in position.

14. Drill two holes through the wood base along one side. The holes should be large enough to fitlarge metal tent stakes. When the launch pad is setup on a grassy field, the stakes will hold thelauncher in place when you yank the pull cord. The launcher is now complete.

Launch Safety Instructions:

1. select a grassy field that measures approximately 30 meters, or 98 feet, across. Place the launcherin the center of the field and anchor it in place with the spikes or tent stakes. If it is a windy day,place the launcher closer to the side of the field from where the wind is coming so that the rocketwill drift onto the field as it comes down.

Completed launcher ready for firing

BottleNeckHold DownBar

Corner IronCarriageBolt

Wood Base

MountingPlate

Hold DownSpike

To Pump

LaunchReleaseCord Hold Down

Spike

Positioning corner irons

35

2. Have each student or student group setup their rocket on the launch pad. Other students shouldstand back several meters. It will be easier to keep observers away by roping off the launch site.

3. After the rocket is attached to the launcher, the student pumping the rocket should put on eye pro-

tection. The rocket should be pumped no higher than about 50 pounds of pressure per square inch.

4. When pressurization is complete, all students should stand in back of the rope for the countdown.5. Before conducting the countdown, be sure the place where the rocket is expected to come down is

clear of people. Launch the rocket when the recovery range is clear by having one student pull thepull cord.

6. Only permit the students launching the rocket to retrieve it.

Summary: Energy is given to the stationary rocket when the stored air pressure inside the bottle isreleased, causing the rocket to go from a state of rest to a state of motion. (1st law) The force of thepressure escaping equals the mass of the rocket times its acceleration. Because the mass of therocket is changing due to the escaping air pressure, force and acceleration will also be changing dur-ing flight. (2nd law) The air being forced out of the nozzle of the bottle results in the bottle beingthrust upward. (3rd law)

Activity Twelve - Altitude TrackingPurpose: Use math skills to determine how high the rocket traveled.

Materials: altitude tracker pattern, altitude calculator pattern, thread or lightweight string, scrapcardboard or poster board, glue, cellophane tape, small washer, brass paper fastener, scissors, razorblade knife and cutting surface, meter or measuring stick, rocket, and launcher

Procedure:

Constructing the Altitude Tracker scope1. Glue the altitude tracker pattern onto a piece of cardboard.

Do not glue the dotted portion of the tracker above thedashed line.

2. Cut out the pattern andcardboard along the out-side edges.

3. Roll the part of the patternnot glued to the cardboard intoa tube and tape it as shown inthe illustration.

4. Punch a tiny hole in the apex ofthe protractor quadrant.

5. slip a thread or lightweight stringthrough the hole. Knot the thread or string on the backside.

6. Complete the tracker by hanging a small washer from theother end of the thread as shown in the diagram to the right.

01020304050

60

7080

90

This Attitude Tracker Belongs to

Sample Altitude Tracker

Altitude Tracker

Launch rockets and measure

altitude with Altitude Tracker

36

01020

3040

5060

7080

90

This Attitude Tracker belongs to___________________________.

Roll this section over and tape theupper edge to the dashed line. Shape the section into a sighting tube.

A lt i tude Tracker

Altitude Tracker Pattern

Procedure:

Constructing the Altitude Calculator

1. Copy the two patterns for the altitude calculator onto heavyweight paper or gluethe patterns on to lightweight poster board. Cut out the patterns.

2. Place the top pattern on a cutting surface and cut out the three windows.3. Join the two patterns together where the center marks are located. Use a

brass paper fastener to hold the pieces together. The pieces should ro-tate smoothly.

(See next page for pattern.)

Procedure:

Using the Altitude Tracker

1. setup a tracking station location a short distance awayfrom the rocket launch site. Depending upon the ex-pected altitude of the rocket, the tracking station shouldbe 5 meters (16.5 ft), 15 meters (49 ft,) or 30 meters(98 ft) away. Generally, a 5-meter distance is sufficientfor paper rockets and antacid-powered rockets. A 15-meter distance is sufficient for bottle rockets, and a30-meter distance is sufficient for model rockets.

2. As a rocket launches, the person doing the tracking willfollow the flight with the sighting tube on the tracker. The tracker should be held like a pistol andkept at the same level as the rocket when it is launched. Continue to aim the tracker at the highestpoint the rocket reached in the sky. Have a second student read the angle that the thread or stringmakes with quadrant protractor. Record the angle.

Procedure:

Determining the Altitude

1. Use the Altitude Calculator to determine the height the rocketreached. To do so, rotate the inner wheel of the calculator sothat the nose of the rocket pointer is aimed at the angle meas-ured in step 2 of the previous procedure.

2. Read the altitude of the rocket by looking in the window.If you use a 5-meter (16.5 ft) baseline, the altitude therocket reached will be in the window beneath the 5.To achieve a more accurate measure, add theheight of the person holding the tracker to cal-culate altitude. If the angle falls between two-degree marks, average the altitude numbersabove and below the marks.

Summary: This activity makes use of simpletrigonometry to determine the altitude a rocketreaches in flight. Accuracy can be increased byhaving two people use an altitude tracker at dif-ferent locations and averaging the results.

Two station tracking uses the

average of the two stations

30 meters 30 metersbaselinebaseline

0

10

20

3040

50607080

90

Al t i t u d eTr a c k e r

This

Attit

ude

Trac

ker B

elong

s to

010

2030405060

70

80

90

Al t i t u d eTr a c k e r

This

Attitu

de Tr

acke

r Belo

ngs t

o

0

10

2030

40506070

80

90

Al t i t u d eTr a c k e r

This

Attitud

e Trac

ker B

elong

s to

15 metersbaseline

?

37

Using the Altitude Tracker

38

90

85

80

75

171 34357.2

28.4 85.1170

11282.4

55.941.2

18.613.710.832.2

64.352

26

8.77.1617.9

35.8

3015

54.212.6

25.2

2110.5

3.52.9

8.717.3

14

7

2.3

1.81.3

44

5.32.6

0.9

0.41.32.6

0 0 0

5.511

21.442.9 70

65

60

555045

40

35

30

2520

15

10

5

0 +

cutout cutout cutout

Directions:1. Rotate the nose of the rocket

to the angle you measured.

2. Look at the number in the window for the distance of the tracking station location from the launch site. The number will tell you the altitude of the rocket in meters.

BASELINE5 15 30 m

++

Altitude Calculator back

Altitude Calculator front

ALT

ITUDE CALCULATOR - BACK W

HEEL

ALTITUDE CALCULATOR

Activity Thirteen - Goddard RocketPurpose: Demonstrate Newton’s Laws of motion by creating and experimenting with flight with aflight-worthy foam rocket that is named after the first man to develop a liquid-fueled rocket in 1926,Robert Goddard. (This particular rocket resembles Goddard’s 1931 rocket.)

Materials: 14 " length of 1 -3/4" outside diameter foam pipe insulation, a foam meat tray for fintemplates, a # 64 rubber band for propulsion, a nylon cable tie to tie the rubber band in the fuselageof the rocket, a metal washer, and a hot glue gun to bond the foam parts together

Procedure: 1. Copy the fin template to the right on a copy machine.2. Place the fin template on the foam meat tray and cut out fins.3. Place the “fin guide” on page 40 around the foam fuselage

to show where to equally — place the fins.4. Hot glue the foam fins to the fuselage by putting the

hot glue on the fin only and placing it on the finguide.

5. Tie the rubber band to the washer and insertthe washer into the fuselage.

6. Pull a cable tie around the nose with theend of the rubber band hanging outand cinch it down tight. Clip the re-maining tail of the cable tie. Drop abit of hot glue over the cut edge ofthe cut cable tie to avoid cutting fingers.

7. To launch, put one thumb in the tail pipe of the rocketand stretch the rubber band with the other.

Summary: The launch of a foam rocket is a gooddemonstration of Newton’s Third Law of motion.The contraction of the rubber band produces anaction force that propels the rocket forwardwhile exerting an opposite and equal forceon the launcher. The foam rocket receivesits entire thrust from the force producedby the elastic rubber band. The thrustof real rockets typically continues forseveral seconds or minutes, causingcontinuous acceleration, until propellants are exhausted. Thefoam rocket gets a quick pull and thrusting is over. Once inflight, it coasts. Furthermore, the mass of the foam rocketdoesn’t change in flight. Real rockets consume propellantsand their total mass diminishes. Nevertheless, the flightof a foam rocket is similar to that of real rockets. Itsmotion and course is affected by gravity and by dragor friction with the atmosphere. For an in-depthexplanation of how the foam Goddard rocketworks and relates to the forces of flight, readthe “background” information athttp://www.nasa.gov/pdf/295787main_Rockets_Foam_Rocket.pdf.

39

Goddard Rocket Fins

40

Goddard Rocket Assembly

When mounting fins, use the hot glue on the meat tray foam,not on the black insulation.

Fin

Fin Guide

Cable Tie

The rubber band tied to the washer is inserted in the fuselage and secured with a cable tie.

Close cable tie then snip off extrapiece using toenail clippers.

Fuselage

Wrap this guide around the 3/4" outside diameter pipe foam tube a little more than 3 "from the rocket's tail pipe. The two ends should meet at the seam of the foam tube. Put asmall piece of tape on this guide to hold it in place. Hot glue one rocket fin on to theseam of the foam tube. The arrows show where the other two fins should be mounted.

Aerospace Dimensions

SPACE ENVIRONMENT

MODULE

Civil Air PatrolMaxwell Air Force Base, Alabama

55

5

Aerospace Dimensions

SPACE ENVIRONMENT

5

Aerospace Dimensions

SPACE ENVIRONMENT

WRITTEN BY

DR. JEFF MONTGOMERY

ANGIE ST. JOhN

DESIGN

BARB PRIBULICK

EDITING

BOB BROOKS

SUSAN MALLETT

PhOTOS AND ILLUSTRATIONS

COURTESY OF NASA AND BOEING

NATIONAL ACADEMIC STANDARD ALIGNMENT

JUDY STONE

PUBLIShED BY

NATIONAL hEADQUARTERS

CIVIL AIR PATROL

AEROSPACE EDUCATION DEPUTY DIRECTORATE

MAXWELL AFB, ALABAMA 36112

ThIRD EDITION

JUNE 2013

INTRODUCTION

ii

The Aerospace Dimensions module, Space Environment, is the fifth of six modules, which com-bined, make up Phases I and II of Civil Air Patrol's Aerospace Education Program for cadets. Eachmodule is meant to stand entirely on its own, so that each can be taught in any order. This enablesnew cadets coming into the program to study the same module, at the same time, with the othercadets. This builds a cohesiveness and cooperation among the cadets and encourages active groupparticipation. This module is also appropriate for middle school students and can be used by teachersto supplement sTEm-related subjects.

Inquiry-based activities were included to enhance the text and provide concept applicability. Theactivities were designed as group activities, but can be done individually, if desired. The activitiesfor this module are located at the end of each chapter.

CONTENTS

iii

Introduction .............................................................................................ii

Contents...................................................................................................iii

National Academic Standard Alignment ..............................................iv

Chapter 1. Space ......................................................................................1

Chapter 2. Stars .....................................................................................14

Chapter 3. Our Solar System: Sun, Moon, and More ........................26

Chapter 4. Our Solar System: Planets .................................................38

iv

National Academic Standard Alignment

1

Learning Outcomes

- Describe the location of space.

- Describe characteristics of space in terms of temperature, pressure, and gravity.

- Define microgravity.

- Define cislunar space.

- Distinguish between interplanetary and interstellar space.

- Define galaxy.

- Identify three types of galaxies.

- Define universe.

Important Terms absolute zero - the point at which all molecules no longer move or have the least amount of

energy; theoretically the absolute coldest temperaturecislunar space - the space between the Earth and the moongalaxy - an enormous collection of stars arranged in a particular shapeinterplanetary space - space located within a solar system; measured from the center of the sun to

the orbit of its outermost planetinterstellar space - the region in space from one solar system to anotherKelvin - unit of measurement based on absolute zero and commonly used by scientists to

measure temperaturemicrogravity - small gravity levels or low gravity; floating conditionspace - region beyond the Earth’s atmosphere where there is very little molecular activityuniverse - all encompassing term that includes everything; planets, galaxies, animals, plants, and humansvacuum - space that is empty or void of molecules Van Allen belts - radiation belts around the Earth filled with charged particles

since the beginning of time, man has looked to the stars with awe and wonder. Our universe hasalways fascinated scientists and other observers. What was once unexplored territory has now be-come the new frontier. many expeditions, missions, satellites, and probes have traveled into thisoverwhelming vastness we call our universe in search of knowledge and understanding. When wetalk about the universe, several words may come to mind. many people think of words like space,stars, planets, and solar systems. This volume on the space environment will define these terms andgive you a basic understanding of our universe.

You might wonder why this is important. All of our volumes have been talking about aerospace,and space is certainly a part of this overall concept. We are no longer limited in our thinking orachieving to the immediate area of Earth’s atmosphere. For years, travel has occurred beyond thatscope. The Us has participated in unmanned and manned space missions for years, and our missionshave included stops at space stations. American astronauts used to assist at the Russian space stationMir. missions now involve astronauts staying in space for extended periods of time on the Interna-

11

2

tional space station. It is conceivable that some of us could travel to space during our lifetime. Let’stake a brief look at some basic information that we should know in our quest for learning about ourspace environment and the universe.

SPACE IS A PLACEFirst, space is a place. It is part of the universe beyond the immediate influence of Earth and its

atmosphere. This does not happen at a particular point, but, rather, happens gradually. You may have

heard space described as a void or a vacuum, but no place in the universe is truly empty. Eventually

the molecules and atoms become so widely spaced that there is no interaction. We call this space.

The Air Force and NAsA define space as beginning at an altitude of 50 miles (80.5 km), and anyone

who reaches this height is awarded astronaut wings. However, 62 miles, or 100 kilometers, is the

most widely accepted altitude where space begins. An object orbiting the Earth has to be at an alti-

tude of 80 or 90 miles (129 to 145 km) to stay in orbit. so, many consider this to be the beginning of

space. The Earth’s atmosphere gradually thins with an increase in altitude, so there is no tangible

boundary or exact point between the Earth’s atmosphere and space.

space is a part of the universe. The universe includes everything: stars, planets, galaxies, ani-

mals, plants, and humans. Let’s talk about the concept of space first and then expand into a discus-

sion of the universe.

3

CHARACTERISTICS OF SPACE

When we describe space as a physical place we must include its characteristics. What is the tem-

perature like in space? What about pressure? Is there gravity in space?

Outer space is almost a vacuum. A vacuum is defined as a space that is empty, meaning the space

has no, or virtually no, molecules. This is true of outer space. Large bodies such as planets, moons,

and stars have such a large gravitational pull that they prevent molecules from floating around in the

space between these large bodies. There are some wandering gas molecules with extremely low den-

sity floating in outer space, so no place in the universe is truly empty. Because these wandering mol-

ecules are so far apart from one another, though, many people think of space as a vacuum.

Oxygen

Regarding a lack of gas molecules, space is characterized by a lack of oxygen. It would be impos-

sible for us to travel or live in space without oxygen. We compensate for this by including an oxygen

supply on all manned space flight projects.

Pressure

What about the pressure in space? As explained in NAsA’s educational product, Suited for Space-

walking, “In space, the pressure is nearly zero. With virtually no pressure from the outside, air inside

an unprotected human’s lungs would immediately rush out in the vacuum of space. Dissolved gases

in body fluids would expand, pushing solids and liquids apart. The skin would expand much like an

inflating balloon. Bubbles would form in the bloodstream and render blood ineffective as a trans-

porter of oxygen and nutrients to the body’s cells. Furthermore, the sudden absence of external pres-

sure balancing the internal pressure of body fluids and gases would rupture fragile tissues, such as

eardrums and capillaries. The net effect on the body would be swelling, tissue damage, and a depri-

vation of oxygen to the brain that would result in unconsciousness in less than 15 seconds.” We com-

pensate for the lack of pressure by providing pressurized spacecrafts and spacesuits for humans.

Temperature

In terms of the average temperature in the

darkness of outer space, generally the tempera-

ture is near absolute zero. Temperature is based

on the movement of molecules, and absolute

zero is the point at which all molecules stop

moving or have the least amount of energy. Ab-

solute zero is written as 0 K (-273° C or -459°

F), which is theoretically the absolute coldest

temperature that could exist. Kelvin, abbreviated

K, is a unit of measurement based on absolute

zero, and it is commonly used by scientists to

measure temperature. Although there is hardly

any movement of molecules in the darkness and

near emptiness of much of outer space, there is

still cosmic microwave background radiation (a

form of electromagnetic radiation filling the Image credit: NASA

universe), which means that the temperature in space is not quite at absolute zero, but rather about

2.725 K (-270° C or -455° F). Keep in mind that this average space temperature of 2.725 K is not the

temperature for every point in space. For example, objects in Earth’s orbit may experience a tempera-

ture of over 393 K (120° C or 248° F) in sunlight areas and lower than 173 K (-100° C or -148° F) in

Earth’s shadow. To combat the temperature extremes, humans are able to control the temperature in-

side a spacecraft or spacesuit. (see temperature illustration on the previous page.)

Gravity

When discussing the characteristics of space, a common misconception is that there is no gravity

in space. most of us have seen pictures of astronauts floating around in space, which leads us to be-

lieve that there is no gravity in space. Floating in outer space occurs because the gravity in space is

much smaller or less than on Earth. small or low gravity is called microgravity.

The prefix micro really means one part in a million, but we use it all of the time to simply mean

something small. That is how we use it when referring to space. To actually go into space where the

Earth’s gravitational pull is one-millionth of that at the surface, you would have to travel 17 times

farther away than the moon. As you know, no human has traveled beyond the moon yet. so, why do

astronauts orbiting the Earth experience a feeling of weightlessness and float? It is because they are

constantly falling around the Earth as they orbit in a state of “free fall.” Rather than traveling to a

distance 17 times farther away than the moon, a microgravity environment can be created by free

fall.

We can create a microgravity environment here on Earth. Imagine riding in an elevator to the top

of a building. When you get to the top, the elevator cables break, causing the elevator and you to fall.

since you and the elevator car are falling together, you feel like you are floating inside the car. You

and the car are acceler-

ating downward at the

same rate due to gravity

alone. If a scale were

present, your weight

would not register be-

cause the scale would

be falling too. NAsA

calls this floating condi-

tion microgravity. While

orbiting the Earth, astro-

nauts experience a mi-

crogravity environment

as they constantly fall

around the Earth. Be-

cause they are traveling

at about 17,500 miles

per hour, they are trav-

eling fast enough to

keep going around and

A B C D

NORMALWEIGHT

HEAVIER THAN

NORMALWEIGHT

LIGHTER THAN

NORMALWEIGHT

NO MEASUREDWEIGHT

Picture D is an example of microgravity

4

5

around the Earth.

“Did you know,” as explained in NAsA’s Suited

for Spacewalking, “that if you stepped off a roof

that was five meters high, it would take you just one

second to reach the ground? In a microgravity envi-

ronment equal to one percent of Earth’s gravita-

tional pull, the same drop would take 10 seconds. In

a microgravity environment equal to one-millionth

of Earth’s gravitational pull, the same drop would

take 1,000 seconds or about 17 minutes.” (see asso-

ciated Activities One, Two, Three, and Four at the

end of the chapter.)

Regions of Space

We can further describe space as cislunar, inter-

planetary, or interstellar space. Cislunar space is

the space between the Earth and the moon. This dis-

tance varies from month to month since the moon’s

orbit around the Earth is elliptical. The average dis-

tance between the Earth and its moon is 237,087

miles (381,555 km).

Cislunar space is not a void nor a vacuum. Part

of the Earth’s magnetosphere is found in cislunar

space. The magnetosphere contains protons, elec-

trons, and magnetic lines of force. Radiation storms

emitting from the sun are also located here. Cislu-

nar space also contains meteoroids, asteroids, and

comets, which we will discuss in an upcoming chapter.

so, you can see cislunar space is far from being void. However, it is not overcrowded either. Ac-

cording to astronauts who have been there, space looks like the void it has been called. Astronaut

Anders (Apollo 8) said, “The sky is very, very stark. The sky is pitch black and the moon is quite

light. The contrast between the sky and the moon is a vivid dark line.”

Interplanetary space is measured from the center of the sun to the orbit of its outermost planet.

In addition to the sun, this portion of space in our solar system includes eight known planets, which

we will explore in Chapter 4. It also contains numerous planetary satellites, dwarf planets, a huge

belt of asteroids, charged particles, magnetic fields, dust, and more. This interplanetary space is often

referred to as the solar system. Then, interstellar space is the distance from one solar system to an-

other.

Now, we know a little about what space is like. We should remember that space is a part of the

universe. The universe is the all-encompassing term that includes everything. Although the universe

includes plants, animals, and humans, we want to talk about the part of the universe that includes

galaxies.

Dimensions and occupants of cislunar space

GALAXIESso, what is a

galaxy? A galaxy

is an enormous

collection of stars,

and these stars are

arranged in a par-

ticular shape.

There are three

main shapes of

galaxies: elliptical,

spiral, and irregu-

lar. Elliptical is

oval shaped. spiral has arms spiraling outward from a center. Irregular has no particular shape.

Our galaxy is the milky Way Galaxy. The milky Way is a huge collection of stars arranged in a

spiral shape. The picture above shows the milky Way from a deep space view. The milky Way has a

dense central bulge with arms spiraling outward. The center of our galaxy contains older red and yel-

low stars, while the arms have mostly hot, younger, blue stars. scientists estimate that the milky

Way probably contains 100 billion other solar systems and stars.

The universe contains many galaxies and is continually expanding. Our sun, which is the center

of our solar system, is but a tiny spot in our galaxy. In fact, there are 200 billion suns in our galaxy,

and our galaxy is just one of millions of galaxies. The smallest galaxies have about 100,000 stars,

while the largest have about 3,000 billion stars.

Our universe is huge! One way to think about this is by using distance. Distance in space is meas-

ured in light years. A light

year is about 6 trillion miles.

Our galaxy is about 150,000

light years across. Again, our

galaxy is only one of mil-

lions of galaxies. Our uni-

verse is so vast it is almost

incomprehensible. so, let’s

not worry about how big it

is, and instead just take a

brief look at the space envi-

ronment around our planet,

Earth. (see associated Activ-

ity Five at the end of the

chapter.)

Irregular galaxy

Milky Way Galaxy - spiral galaxy Elliptical galaxy

6

7

SPACE ENVIRONMENT AROUND THE EARTHNAsA’s “Radbelts” Web site explains a great deal about the space environment around Earth

(http://radbelts.gsfc.nasa.gov/). “Earth is surrounded by a magnetic field that looks something likethe field you seearound a toy magnetwhen you use iron fil-ings to make it standout better. You haveprobably seen thisdemonstrated in a sci-ence class. Earth’smagnetic field isshaped something likea comet, with a long,invisible tail of mag-netism stretching mil-lions of miles beyondthe moon on the op-posite side of the sun.This magnetic fieldcan act like a bottle,trapping fast-movingcharged particleswithin an invisiblemagnetic prison. The particles are so numerous that they form into donut-shaped clouds with theEarth at the center, and stretching thousands of miles above Earth’s surface above the equator. scien-tists call these the ‘Van Allen Radiation Belts’ because they were first discovered by Dr. James VanAllen using one of the first satellites launched by NAsA in 1958.

The word ‘radiation’ has to do with energy or matter moving through space. There are manyforms of radiation that astronomers and physicists know about. sunlight is a form of electromagneticradiation produced by the sun, but so is ultraviolet radiation, infrared radiation, and gamma radia-tion. Any heated body produces electromagnetic radiation. We also use the term ‘radiation’ to de-scribe fast-moving particles of matter. One form of these found in space is cosmic radiation or morecommonly referred to as ‘cosmic rays.’ They are not made of light energy, but are actually the nucleiof atoms such as hydrogen, helium, iron, and others which travel through space at hundreds of thou-sands of kilometers per second. some electrons in the cosmic rays travel at nearly the speed of light.Like other forms of radiation, they carry energy away from the place where they were created. Whenthey are absorbed, they deliver this energy to the body that absorbs them.

The Van Allen Belts are formed by clouds and currents of particles that are trapped in Earth’smagnetic field like fireflies trapped in a magnetic bottle. Artists like to draw them as though theylook like dense clouds of gas. In fact, they are so dilute that astronauts don’t even see them or feelthem when they are outside in their space suits. Because you can’t see them from the ground at all,scientists didn’t know they existed until they could put sensitive instruments inside satellites andstudy these clouds directly. They only had a hunch that something like them existed because theywere predicted by certain mathematical models.

The Inner Belt (shown in blue above), between 600 and 3,000 miles (1,000 and 5,000 km), con-tains high-energy protons carrying energies of about 100 million volts, and electrons with energies of

Van Allen Radiation Belts – Credit: NASA GSFC

about 1 to 3 million volts. This is the belt that is a real hazard to astronauts working in space.The Outer Belt (shown in purple), between 9,000 and 15,000 miles (16,000 and 24,000 km), con-

sists of mostly electrons with energies of 5 to 20 million volts. This is the belt that is a hazard tocommunication satellites whose sensitive circuits can get damaged by the fast-moving particles.

Where do the particles in the belts come from? One line of thinking says that they might comefrom the sun. The sun is, after all, a powerful and abundant source for particles like the ones foundin the belts. A second idea is that they were once cosmic rays from outside the solar system that gottrapped by Earth’s magnetic field as they traveled by. A third idea is that they may be atoms and nu-clei from Earth’s atmosphere that have been fantastically boosted in energy to millions of volts bysome process we don’t yet understand. The particles are not labeled with their place of origin. Thismakes it very difficult for scientists to sort out how each of these ideas actually contributes to thebelts themselves. But if you took a survey of space scientists today, they would probably agree thatthe first two ideas are the most likely.

Anyone who works and lives in space, or has satellites working in space, will be very concernedabout the radiation belts. Radiation belts contain very high energy particles that can pass through theskin of a satellite and damage the sensitive circuitry inside. If the circuitry controls the way the satel-lite is pointing its antenna, the satellite can veer out of lock with ground-based receivers and be tem-porarily “lost.” Unless satellite operators can anticipate and correct this problem, the satellite will bepermanently lost. During the current sunspot cycle, which began in 1996, we have lost over $2 bil-lion in satellites from these kinds of problems. scientists want to learn as much about the radiationbelts as they can, so that they can better predict what will happen to satellites and humans operatingin space.

Radiation belts and the particles that they contain are an important element of the space weathersystem. space weather is a term that scientists use when they describe the changing conditions in theflows of matter and energy in space. These changes can have serious effects on the way that expen-sive and vital satellites operate. They can also have a big effect on the health of astronauts workingand living in space.

Anytime that satellite technology or astronauts are being affected by forms of radiation in space,such as fast-moving particles and X-rays, this usually causes some changes to occur. most of thetime these changes are so minor that they have no real consequences either to the way that the satel-lite operates or the health of the astronaut. But sometimes, and especially during a severe solar stormor “space weather event,” the conditions in space can change drastically. The term “space radiationeffects” has to do with all of the different ways that these severe conditions can significantly changethe way a satellite operates, or the health of an astronaut working and living in space.

When a high-energy particle penetrates a satellite’s metal skin, its energy can be absorbed by mi-croscopic electrical components in the circuitry of a satellite. The switch can be changed from “on”to “off ” momentarily, or, if the energy is high enough, this can be a permanent change. If that switchis a piece of data in the satellite’s memory, or a digit in a command or program, it can suddenlycause the satellite to veer out of control until a human operator on the ground can correct this prob-lem. If the particle happens to collide with one of the pixel elements in the satellite’s star-trackingcamera, a false star might be created and this can confuse the satellite to think it is not pointing in theright direction. Other satellite effects can be even more dramatic. When severe solar storms affectEarth’s upper atmosphere, the atmosphere heats up slightly and expands deeper into space. satelliteswill feel more friction with the air they are passing through, and this will seriously affect their orbits.

For astronauts, space radiation effects have to do with the amount of radiation (usually x-rays)that pass through the walls of their spacecraft or space station and penetrate into the body of the as-tronaut. most people have an instinctive fear of radiation and its potential biological effects. No mat-

8

9

ter where you live, you receive a free dose each day of environmental radiation which adds up to 360millirems (4- 5 chest X-rays) per year, and you have no control over this. The daily dosage of radia-tion on the Space Station is about equal to 8 chest X-rays per day.

But what about the Apollo astronauts who traveled the most intense regions of the belts in theirjourney to the moon? Fortunately, the travel time through the belts was only about 30 minutes. Theiractual radiation exposures inside the Apollo space capsule were not much more than the total dosereceived by space shuttle astronauts in a one-week stay in orbit. This fact counters some popularspeculations that the moon landings were a hoax because astronauts would have instantly died asthey made the travel through the belts.

In reality, the Apollo astronauts might have experienced minor radiation sickness if they had beenin their spacesuits on a spacewalk, but no spacewalk was ever scheduled for this very reason. Themetal shielding provided by the Apollo space capsule walls was more than enough to protect the as-tronauts from all but the most energetic and rare particles.” Consider learning more about space radi-ation and the Van Allen Belts athttp://radbelts.gsfc.nasa.gov/out-reach/index.html.

The magnetosphere begins atabout 215 miles (346 km) abovethe Earth’s surface and extendsinto interplanetary space. Themagnetosphere is characterized byits magnetic field of force, whichsurrounds the Earth. This forcefield is strongest at the poles andweakest at the equator.

The magnetosphere’s forcefield is affected by solar winds.solar winds strike the magneto-sphere with such force that itforms a bow shock wave. The re-sulting bow shock wave distortsthe Earth’s magnetosphere.

You have probably heard of theaurora borealis and the aurora australis. The aurora borealis (or northern lights) flashes brilliant col-ors in varying patterns across the northern skies, and the aurora australis presents a similar display inthe southern Hemisphere. Observers have determined that these displays occur at heights rangingfrom 60 to 600 miles above the Earth’s surface. It has also been determined that these displays areassociated with a zone of electrically-charged layers in the upper atmosphere called the ionosphere.

The ionosphere is a part of the atmosphere divided by its electrical activity. It gets its name fromthe gas particles that are ionized or charged. The ionosphere was discovered early in the twentiethcentury when scientists learned that radio waves were transmitted in the atmosphere and were re-flected back.

The ionosphere is filled with ions. Ions are atoms that carry a positive or negative electricalcharge as a result of losing or gaining one or more electrons. These ions concentrate in certain partsof the ionosphere and reflect radio waves.

The ionosphere is caused by powerful ultraviolet radiation from the sun and the ultra high fre-quency cosmic rays from the stars. This radiation bombards the scattered atoms and molecules of ni-trogen, oxygen, and other gases and knocks some of the electrons out of the atoms.

Regions of the Magnetosphere

SummaryTo briefly summarize this chapter, everything is part of the universe. space, stars, planets, galax-

ies, plants, animals, and humans are all part of the universe. Temperature, atmosphere, gravity, mag-netic fields, and other factors vary at different places within the universe. There are even differenttypes of galaxies in our universe, but all galaxies are made up of an arrangement of huge masses ofglowing objects: stars. We will shed a little more light on our universe by looking at stars in the nextchapter.

10

11

STOP! safety Precautions: Water on floors or tile can create a walking hazard. Also, make sure

electrical cords and appliances are removed from the area before doing these activities.

Activity One - Creating the Microgravity of SpacePurpose: The purpose of this activity is to demonstrate that free fall eliminates the local effects of gravity.

Materials: water, plastic-drinking cup, large cookie sheet with at least one edge that doesn’t have a rim,empty soda pop can, a large pail (catch basin), towels (old bath towels for cleaning spills), and a step lad-der

Procedure:

1. Place the catch basin in the center of an open area in your meeting room.2. Fill the plastic cup with water.3. Place the cookie sheet over the opening of the cup. Hold the cup

tight to the cookie sheet while quickly inverting the sheet and cup.4. Hold the cookie sheet and cup high above the catch basin.

(This is where you may want to use the stepladder to get higher.)5. While holding the cookie sheet level, quickly pull the

cookie sheet straight out from under the cup.6. The cup and the water will fall together.

Summary: This activity creates a microgravity environment similar to what you would find in space.In this activity, the cookie sheet holds the cup and water in place. Once the cookie sheet is removed, thewater and cup fall together in a state of free fall, simulating microgravity. In space, as an object orbitsthe Earth the state of free fall remains constant until the object is acted on by another opposing force.some sort of drag would lower the speed of the orbit returning the object to Earth. some sort of thrustwould make the object travel faster and end up moving out of Earth’s orbit.

Activity Two - The Can ThrowPurpose: This activity also demonstrates microgravity and objects in a state of freefall.

Materials: empty aluminum soft drink can, sharp nail,catch basin, water, and towels

Procedures:

1. Punch a small hole with a nail near the bottom of an empty soft drink can.2. Close the hole with your thumb and fill the can with water.

3. While holding the can over a catch basin, remove your thumb toshow that the water falls out of the can.

4. Close the hole again and stand back about 2 meters (approx 6 ft)from the basin. Toss the can through the air to the basin, beingcareful not to rotate the can in flight.

C O L A

C O L A

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Activity Three - Surface Tension and MicrogravityPurpose: Use observation skills to compare shapes and sizes ofdrops of water that are falling freely through the air and that arelying on a solid surface. This activity demonstrates surface tensionand how it changes the shape of the fluid at rest.

Materials: water, liquid dish detergent, toothpicks, eyedroppers,wax paper squares (20 x 20 cm or 7.9 inches x 7.9 inches), paper,and pencil for sketching

Procedures:

1. Fill an eyedropper with water.2. Carefully squeeze the bulb of the dropper to form a drop at the end.3. As the water drops through the air, sketch the shape of the water drop. Repeat and sketch several

drops. Compare the shapes and the sizes.4. Place a small drop of water on a square of wax paper. sketch the shape. measure the diameter and

height as best you can. Add a second drop of water. sketch and measure.5. Continue adding water to the first drop. What happens to the shape? 6. With the dropper, try to pull the drop over the wax paper. At some point, friction overcomes the

surface tension and the drop breaks up. How large of a drop can you pull in one piece?7. Add a small amount of liquid detergent to the drop. What happens?

Summary: surface tension is a property of liquids wherein the surface of a liquid acts like a thin,easily bendable elastic covering. When water drops fall, they are spherical. When the water drophits a surface, the molecules are attracted across the surface and inward. This causes the water to tryto pull itself up into a shape that has the least surface area possible – the sphere. Because of gravity,the drops resting on a surface will fatten out somewhat. If liquid detergent is added, the soap mole-cules bond better than the water molecules, so the water molecules spread out more. The importanceof surface tension research in microgravity is that surface tension driven flows can interfere with experiments involving fluids.

Activity Four - Shoot a Cannonball into OrbitPurpose: Observe how freefall works by launching virtual cannonballs into space, and how objectsstay in orbit around the Earth.

Materials: Computer with internet connection

Procedures:

1. Go to http://spaceplace.jpl.nasa.gov/en/kids/orbits1.shtml.2. select various amounts of gunpowder and click fire.

5. Observe the can as it falls through the air.  The water will not fall out of the can during the fallthrough the air.

Summary: This activity reinforced the concept of microgravity and freefall. While the cup is sta-tionary, the water pours out, pulled by gravity; however, while the cup is falling, the water remainsinside the cup the entire time it falls, as the water is falling at the same rate as the can.

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3. Observe what happens to the cannonball.4. Use the chart on the next page to explain what happens to the cannonball for each amount of

gunpowder used.5. In your own words, explain what this activity

teaches you about orbiting the Earth.

Summary: In order for an object to orbit Earth, arocket must launch it to the correct height and pro-vide the object with enough “forward” speed. Ifthere is not enough “forward” speed, the object re-turns to Earth; too much speed results in the objectzooming away from Earth. This activity reinforcesthe concepts of microgravity, freefall, and orbit.

Amount of gunpowder

1 bag2 bag3 bag4 bag5 bag

What happened

Activity Five - The Expanding UniversePurpose: This activity demonstrates the concept of the expanding universe.

Materials: balloon, marker, twist tie or paper clip, measuring tape, paper, and pencil

Procedures:

1. Partially inflate the balloon. Fasten the neck of the balloon with the twist tie or clip.2. make several dots around the balloon and label each dot with numbers (1, 2, 3, and so on). see di-

agram below.3. measure and record the distance between each of the dots.4. Remove the twist or clip, blow more air into the balloon and re-fasten the twist around the neck of

the balloon.5. measure and record the distance between each of the dots again.6. Remove the twist, fully inflate the balloon, and re-fasten the twist around the neck of the balloon.7. measure and record the distance between each of the dots a third time.8. Discuss what happened to the dots as more air was put into the balloon. Discuss how this is like

the expanding universe.

Summary: This activity simply showsthat when more air is added to the bal-loon, the dots become farther apart.The dots represent stars, so as the air isexpanded, the stars are farther apart.some scientists believe that the uni-verse is still expanding.

1 2 3 4 5 1 2 3 4 5 1 2 3 4 5

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Learning Outcomes- Define star.- Define nebula.- Describe the life cycle of a star.- Interpret a Hertzsprung Russell diagram.

Important Terms black hole - a region in space where no radiation is emittedconstellation - a grouping of stars, named after mythical figures and animalslight year - the distance light travels in one Earth year magnitude - measure of the brightness of a starnebula – giant cloud of gas and dustparsec – distance equal to 3.26 light years pulsar - pulsating star that flashes electromagnetic emissions in a set patternstar - a body of hot gases

STARS IN THE NIGHT SKYHave you ever looked at the sky on a clear night, picked out a bright shining dot in the sky, and

wondered if you were looking at a star or a planet? A star is a huge mass of hot gases. A star pro-duces its own light due to nuclear reactions in its core. (A nuclear reaction in a star causes atoms inthe star to change. This process results in the release of energy.) Planets and moons CANNOT createtheir own light. Planets and moons that appear as shining dots in the sky are reflecting sunlight. so,it may be difficult for you to determine if the light you see in the night sky is being reflected fromthe object or generated from within the object. When stargazing, you may want to use a star map tohelp you identify the stars visible in your location.

Our sun is a star. Our sun is the only star in our solar system, but when we look into the sky on aclear, dark night, we see a sky painted with a seemingly endless number of stars. Even though all thestars we see with our eyes are stars that are located in our own milky Way Galaxy, they are very faraway from us. In fact, the name of the closest star to us beyond the sun is Proxima Centauri (alsocalled Alpha Centauri C). Without a telescope, it cannot be seen in the night sky, and with a tele-scope, it can only be viewed from the southern hemisphere. Its stellar neighbors, Alpha Centauri Aand Alpha Centauri B, are bright enough to be seen from Earth with the naked eye. Proxima Centauriis 4.2 light years from our sun, and Alpha Centauri A and B are about 4.4 light years away. But,what is a light year?

MEASURING DISTANCESDistances between the stars and solar systems vary and involve such high numbers of miles that it

is staggering. scientists, therefore, do not use miles, kilometers, or even astronomical units (which

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you will learn about later) to measure distances between stars. Instead, scientists use the unit ofmeasurement known as light years and parsecs to measure such extreme distances. A light year isthe distance light can travel in one Earth year. This amounts to 5 trillion 878 billion statute miles(5,878,000,000,000 miles). Just how far is that? The book The Stargazer’s Guide to the Galaxy putsit into prospective by stating, “You would have to make 32,000 round trips to the sun and back totravel the distance of one light year.” so, our nearest star, Proxima Centauri, is 4.2 light years (25trillion miles) away. This means that the light from Proxima Centauri takes a little over four Earthyears to reach us. When the number of light years between locations gets very large, parsecs areused; one parsec is 3.26 light years, or 19.2 trillion miles.

Why can some stars that are far away from Earth be seen and others cannot? It is due to theirbrightness and distance from Earth. A star has a number of properties such as size, mass, tempera-ture, color, and brightness. Additionally, stars vary in the amount of energy they generate in the formof light and heat energy. Different amounts of energy released result in stars having different temper-atures, and the temperature of a star determines its color. so, whether or not a star is visible fromEarth using our eyes only depends on the properties of the star, including the distance of the starfrom Earth. (see associated Activity six at the end of the chapter.)

MEASURING BRIGHTNESSMagnitude is a measure of the brightness of a star. The lower the magnitude number, the brighter

the star. A higher magnitude number indicates a dimmer star. For example, a star of magnitude 1.1 isbrighter than a star whose magnitude is 4.5. some stars have a magnitude with a negative number,which indicates a really bright star.

There are two different kinds of magnitude for a star: apparent magnitude and absolute magni-tude. Apparent magnitude is the measure of the brightness of a star as viewed from Earth. Absolutemagnitude is the star’s brightness as it would be viewed from a distance of 10 parsecs, or 32.6 lightyears from Earth, regardless of actually how far away the star is from Earth. Absolute magnitudegives us a better idea of the true brightness of a star. For example, the apparent magnitude of the sunis -26.72, which indicates a very bright star. The reason the sun appears so bright and has such a lowapparent magnitude is because it is the closest star to Earth. The absolute magnitude of the sun (thebrightness of the sun if it were viewed 32.6 light years from Earth), however, is +4.8. From Earth, a+4.8 magnitude star would appeardim.

Astronomers are scientists whostudy stars and other celestial bodies inspace. An important tool that as-tronomers use to graphically organizeinformation about stars and to see therelationships among them is the Hertzsprung-Russell diagram, calledthe H-R diagram. It is named after aDenmark astronomer and an Americanastronomer who independently devel-oped the first kind of this type of dia-gram in the early 1900s. The diagramplots stars according to their absolutemagnitude and surface temperature.

many H-R diagrams also reveal astar’s classification. stars are classifiedaccording to temperature, and a star’s

Hertzsprung-Russell or H-R Diagram

16

surface temperature is used to place it in one, single-letter classification. The letters O, B, A, F, G, K,and m each represent stars with a specific temperature range. The letters are arranged in decreasingtemperature, with class O stars being the hottest and blue in color. Class m stars are the coolest in tem-

perature and are the color red. Our sun has a surface temperature of about 5,800 K; therefore, it is clas-sified as a G star, where stars range in temperature from 5,500-6,000 K. (Reminder: Do not confusethis measurment of K with the star class of K. K stands for Kelvin and is a unit of measurement usedby scientists to measure temperature.)

Just as people go through different stages from birth to death, stars go through different stages intheir life cycle. H-R diagrams reveal where stars are in their life cycle, a reflected by several charac-teristics, including temperture. (see associated Activity seven at the end of the chapter.)

A STAR’S LIFEGalaxies contain giant clouds called nebulae that are spread throughout the galaxy. A nebula is a

cloud of gas and dust. The gases in these nebulae are made up of mostly hydrogen and a smallamount of helium. Nebulae occur in regions where stars are forming, have exploded, or are sheddingtheir outer layers toward the end of their lives. A nebula may be dark or bright. The dark nebulae arevast clouds of matter that have not yet formed into stars. The bright nebulae may be studded withstars and send forth brilliant arrays of color. some bright nebulae, such as the Crab Nebula, are the

Horsehead NebulaNebulae

17

remnants of supernova stars that have exploded. Nebulae spin andmove and give a galaxy shape. Nebulae can also produce stars.

As a star begins to form, clumps of gases and dust come together.most stars are composed of hydrogen and helium in their gaseousstate. stars have their own gravity and this gravity brings in andholds the gases together. The gravity pulls inward and the pressurefrom the hot gases drives outward. This creates a balance, prevent-ing the star from collapsing under its own weight. The intense heatof a nebulae star releases energy in the form of light and heat. Astar’s fuel is the hydrogen that it is converting to helium. Once thehydrogen is gone, the star can begin converting helium into carbon,which is a heavier element than hydrogen. some massive stars caneven generate elements heavier than carbon. The bottom line, how-ever, is that once the star’s fuel is gone, the balance between itsgravity and pressure is gone. This will result in the star’s death. Let’sinvestigate a little further about the life cycle of stars.

LIFE CYCLE OF STARSA protostar is the term used to identify a ball-shaped material within a nebula that could become a

star. Just like humans begin as a fetus in the mother’s womb, a star begins as a protostar in a nebula.During this time, clumps of gas and dust are coming together at a central gravitational point some-where within the nebula, and the disk of gas and dust surrounding the protostar spins. As gravitydraws in more clumps, more atoms are colliding and generating heat. Nuclear fusion, which occurswhen temperatures are hot enough and pressure is great enough for the nuclei of atoms to fuse to-gether rather than being repelled, can occur with very light elements at around 1 million Kelvin (K).This will cause the protostar to glow. Over a long period of time, the protostar may become a star ifits core gets dense enough and hot enough to begin hydrogen fusion. Hydrogen fusion, a type of nu-clear fusion, occurs in a star at around 10 million K. When hydrogen fusion occurs in a star, the hy-drogen atoms fuse together to form the heavier element helium. When hydrogen fusion occurs, theprotostar has become a star, and the mass of the new star will determine how long it lives and how itwill die.

Once hydrogen fusion is occurring and the star is no longer growing, a star enters the main se-quence phase, where it will spend the majority of its life. You might think of this phase as encom-passing early life through adulthood. During this time the star is burning its fuel, hydrogen. Thisresults in hydro-gen atoms fusingtogether to formhelium in the coreof the star. Thestar will do thisfor the majority ofits life. If the staris a high mass star,it may spend onlya few millionyears in the mainsequence phase. A

Star balance

The fate of a star depends on its mass (size not to scale)

White Dwarf

Neutron Star

Black Hole

Low to Average

Mass Star

Large Mass Star

Very Large

Mass Star

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high mass star is described as a star that has 8 times or more the mass of the sun. A medium massstar is described as having less than 8 times the mass of the sun, but at least 0.5 times the mass of thesun. If a star has medium mass, like our sun, it spends billions of years in the main sequence phase.Low mass stars are described as having less than 0.5 the mass of the sun. If the star is a low massstar, it is believed that it will spend hundreds of billions of years, perhaps even trillions of years, inthe main sequence stage. The lower the mass of a star, the longer the star’s life. The higher the massof a star, the shorter the life of the star. (A short life is really millions of years, compared to billionsor trillions of years.)

Medium Mass Starsmedium-sized and medium mass stars like our sun will live for billions of years. stars like our

sun will expand into a red giant star toward the end of their lives. A red giant star’s hydrogen fusionstops in its core, causing the star to begin to shrink inward due to gravity becoming greater than thegas pressure pushing outward. As this happens, it causes the star to heat up more, causing hydrogenoutside its core to begin fusing. When that happens, the star’s outer layers will expand a great deal.The surface temperature of a red giant cools to about 3,000 K as the heat spreads across a muchlarger surface area. The size of the star makes it appear bright, and the surface temperature of the starcauses it to be red in color. (Remember that the surface temperature of a star affects its color.) Theinternal temperature of the red giant will get hot enough to support helium fusion in its core. Once ithas burned all of its helium and once the core is no longer hot enough to support nuclear fusion, thestar will begin to contract again. This time, it will cause such a great amount of energy to be releasedthat the star will balloon out again. Just how large can a red giant become? It is believed that whenour sun becomes a red giant, it will grow so large that it could expand as far as the orbit of Earth,and maybe mars! Think of a red giant star as a middle-aged star.

After millions of years, or maybe even close to a billion years living as a red giant star, the sunwill eventually collapse to become a white dwarf, which is the remaining core of the star. (Remem-ber that it will collapse because its fuel supply is gone, so it can no longer maintain a balance be-tween gravity pulling material in and the gas pressure going outward.) The outer layers of the once

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red giant blow off and become a nebula. The clouds of gas and dust can continue to move away re-vealing just the white dwarf. As a star becomes a white dwarf, it has a glowing hot temperature ofaround 100,000 K. White dwarfs have a mass about 1.4 times that of the sun, and for many, theirsize will be about the size of the Earth. Although a white dwarf has no more fuel, it will cool veryslowly. This dense star will glow until it has completely cooled, which may take billions of years.Once it no longer gives off any light, it becomes a black dwarf, marking the end of the star’s lifecycle. since scientists believe that the universe isn’t old enough to contain any black dwarfs yet, sci-entists report that there are currently no black dwarfs in existence.

High Mass StarA high mass star will not end its life as a black

dwarf. Once it moves out of the main sequencephase, it will become a red supergiant. stars with asolar mass at least 8 times that of the sun will beable to fuse together heavier elements. As was thecase with the red giant fusing hydrogen outside itscore, a red supergiant will be able to fuse heliumoutside of its core, and fuse hydrogen in a layer be-yond the helium fusion. Different types of fusionwill continue to take place in the core and in theother layers of the star due to the extreme tempera-ture and pressure of the massive star. Elements,such as oxygen, nitrogen, and iron, will be created.The star’s fuels will eventually run out, and the ironatoms will release a huge amount of energy. Whenthis happens, the massive supergiant will explode. A star that explodes is called a supernova. Whenthis occurs, matter is blasted out in many directions. This material can be used to create new stars innew nebulae.

The remaining core of a supernova will either be a neutron star or a black hole. The remainingcore of a supernova becomes a neutron star if it has less than 3 times the mass of the sun. A neutronstar is made up of neutrons, and its initial temperature is around 10 million K. It is difficult to detectneutron stars, however, because of their small size. They are much smaller than a white dwarf. Re-member that a white dwarf is about the size of Earth. A neutron star is a sphere that is typically about12 miles (20 km) in diameter. Although small in size, one teaspoonful of a neutron star would weighabout a billion tons on Earth. That’s dense!

As NAsA and World Book report, “A neutron star ac-tually emits two continuous beams of radio energy. Thebeams flow away from the star in opposite directions. Asthe star rotates, the beams sweep around in space likesearchlight beams. If one of the beams periodicallysweeps over Earth, a radio telescope can detect it as a se-ries of pulses. The telescope detects one pulse for eachrevolution of the star. A star that is detected in this wayis known as a pulsar.” A pulsar is known as a pulsatingstar because it flashes electromagnetic emissions in a setpattern. The astronomers who discovered a pulsar firstthought Earth was being sent signals from intelligent

Supernova

Pulsar is in the center of the supernova Kes 75

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life in another solar system.If the remaining core of a supernova has 3 or more

times the mass of the sun, it implodes creating a black

hole. Its gravitational force is so strong, nothing can es-cape from it. As reported on NAsA’s Imagine the Uni-verse Web site, “But contrary to popular myth, a blackhole is not a cosmic vacuum cleaner. If our sun wassuddenly replaced with a black hole of the same mass,the Earth’s orbit around the sun would be unchanged.(Of course the Earth’s temperature would change, andthere would be no solar wind or solar magnetic stormsaffecting us.) To be ‘sucked’ into a black hole, one hasto cross inside the schwarzschild radius. At this radius,the escape speed is equal to the speed of light, and oncelight passes through, even it cannot escape. If the sun was replaced with a black hole that had thesame mass as the sun, the schwarzschild radius would be 3 km, or 1.9 miles, (compared to the sun’sradius of nearly 700,000 km or 434,960 miles). Hence, the Earth would have to get very close to getsucked into a black hole at the center of our solar system.”

Black holes can be detected by X-rays that are shed as matter is drawn towards the hole. As atomsmove closer to the black hole, they heat up. When the atoms heat up to a few million K, they give offX-rays. These X-rays are released before they cross the schwarzschild radius, and we can, therefore,detect them.

Low Mass StarsAs mentioned earlier, low mass stars

have the longest lives. The low massstars have a solar mass of about lessthan half the mass of the sun down toabout a 0.08 solar mass. They have acooler temperature than intermediateand high mass stars. Red dwarfs are lowmass stars and are the most commonkind of stars in the universe. Our neareststar, beyond the sun, Proximus Cen-tauri, is a red dwarf. Red dwarfs cannotbe seen using just our eyes. After theirlong duration as a main sequence star,they will become white dwarfs andeventually black dwarfs.

It is possible for an object with lessthan 0.08 solar mass to form; however,these objects are known as brown dwarfs, or failed stars. The failed stars are too cool to ever achievehydrogen fusion. They are very hard to detect because they are so small and extremely dim.

Black Hole

In a binary star system known as J0806, two dense white dwarf

stars orbit each other. The stars seem destined to merge.

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MULTIPLE STARSOf stars that do form, many

have a second star with whichthey share the same center ofgravity. The brighter of the two iscalled the primary star and theother is called the companionstar. About half of all stars comein pairs with the stars sharing thesame gravitational center. Theseare called binary stars. Whenlooking at the night sky, a starthat looks like a single shiningstar could actually be part of a bi-nary system.

A constellation is a grouping of stars. Hundreds of years ago, early astronomers divided stars intogroups and made imaginary figures out of them. Things like a lion, a scorpion, or a dog were used.This is how constellations were named. The stars in these constellations are not really related; theyonly appear to be as we view them from Earth. There are 88 constellations in use by astronomerstoday. some of the more well known ones are: Ursa major (the Big Dipper is part of it), Orion, andCassiopeia. (see associated Activity Eight at the end of the chapter.)

SummaryThis chapter revealed to you interesting information about stars. stars are huge masses of gases

that give off light and heat energy due to nuclear fusion occurring in their cores. Remember that astar’s mass will determine how long it will live and how it will die.

The next chapter begins a study on our solar system, looking specifically at our sun, moon, and afew other celestial bodies, such as comets, meteors, and asteroids.

(a) Southern horizon, summer (b) Southern horizon, winter

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Activity Seven - Measuring the Brightness of the StarsPurpose: This activity is designed to determine approximate magnitude of stars.

Materials: 2 pieces of cardboard (or 2 file folders), a strip of clear cellophane, nickel, pencil, scis-

sors or exacto knife, stapler, and ruler

Procedures:

1. Cut two pieces of cardboard, 11” long by 2-3/4” wide.

Activity Six - Analyzing StarlightPurpose: The purpose of this activity is to show the difference in wavelengths of various light sourcesby making a simple spectroscope.

Materials: You must plan ahead, and this activity involves a cost. To do this activity you must pur-chase diffraction grating. Edmund scientific, 101 East Glouchester Pike, Barrington, New Jersey08007-1830 sells it. Their phone number is (609) 573-6250 and their website is www.scientificson-line.com. Two sheets of diffraction grating measuring 6"x12" costs less than $10. These sheets willneed to be cut; one sheet will make 18 two-inch squares. You also need one cardboard tube per per-son (paper towels, toilet tissue, or gift wrapping tubes), scissors or hobby knives, cellophane tape,colored markers or pencils, typing or computer paper, and flashlights or other light sources. (Twenty-five diffraction gratings mounted in 2"x2" cardboard slide mounts can be purchased for $21.95.These can be used straight from the package to build a set of spectroscopes.)

Procedures:

1. Cover both ends of a cardboard tube with paper and fasten with tape.2. make a thin slit in the paper at one end of the tube. (Only a narrow band of light should show

through this slit.)3. make a small hole (1/8") in the paper at the other end of the tube.4. Put the diffraction grating over the small hole and fasten it with tape.5. Point the slit toward an available light source. Use a flashlight or other light source, do not look

directly at the sun.6. move the tube slowly to the right or left so as to make an image appear.7. Using a sheet of paper, sketch the light pattern observed using the colored markers or pencils.8. Observe two other light sources, if possible, and sketch the light patterns observed.9. Compare and discuss each light-source pattern.

Summary: A diffraction grating is a tool that separates colors in light. Using this tool helps to createa spectroscope, which will allow you to see the light patterns and color spectrums of different lightsources. stars give off light, and as such, they have different light patterns. The spectroscope canhelp you see the light patterns of stars in the night sky.

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11"

1 1/2" 3 1/2" 5 1/2" 7 1/2" 9 1/2"

2 3/4"

1

5

7

Magnitude5 Magnitude4 Magnitude3

Magnitude2 Magnitude1

2

6

8

3 4

One Layer of ClearCellophane Two Layers

Tape

Staple

Three Layers Four Layers Five Layers

Steps

Steps

Steps 9

2. Use a ruler to mark one cardboard at five equidistant points: 1-1/2”, 3-1/2”, 5-1/2”, 7-1/2”, and 9-1/2”.

3. Use a nickel to trace a circle over each of the marks, centering the circles between the top and the

bottom edges of the cardboard strip. Carefully cut out the five circles.

4. Trace the cutouts onto the second piece of cardboard. Carefully cut out these five circles, too.

5. Cut 15 squares of cellophane, each 1-1/2”x1-1/2”.

6. Working with one strip of cardboard, cover the first hole with one square of cellophane; cover the

second hole with two squares of cellophane; cover the third hole with three squares of cellophane,

the fourth hole with four squares of cellophane; and cover the fifth hole with five squares of cello-

phane. Use small pieces of tape to secure the squares, as necessary.

7. Carefully place the second piece of cardboard on top of the secured cellophane squares,

being certain to line up the holes in the two pieces of cardboard. staple the cardboard strips to-

gether.

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Activity Eight - Astronomy In A TubePurpose: Become familiar with star patterns (constellations) visible in the night sky.

Materials: an empty Pringles potato chip can with its opaque plastic lid, black construction paper,hammer, nail, push pin (or similar item), scissors, constellation pattern, silver marker (or similarwriting tool)

Procedures:

1. Draw a constellation pattern from the patterns below on a 2.75 inch circular piece of black con-struction paper using a silver marker or some other visible writing tool.

8. Label the hole covered with five squares of cellophane as magnitude 1; label the others in order,

with the hole having only one piece of cellophane over it being labeled as magnitude 5.

9. To use the magnitude strip begin by looking at a star using only your uncovered eye. Then look atthe star through the magnitude strip, looking through hole 1. If you can see the star through holenumber 1, the star is a first magnitude (or brighter) star. If you cannot see it, try looking throughthe hole 2. Keep moving down the magnitude strip until you can see the star. stars that are seenthrough the 4th hole are fourth magnitude stars; stars that can not be seen through the fifth hole,but can be seen with the uncovered eye, are sixth magnitude stars.

Summary: magnitude refers to the brightness of a star. Observing stars through the magnitude stripreveals the approximate magnitude of the stars, ranging from a first magnitude star (very bright andcan be seen through five layers of cellophane) to a sixth magnitude star (dim stars that could not beseen through the magnitude 5 hole on the magnitude strip, but could only be seen with a clear viewfrom the uncovered eye). Knowing the approximate magnitude of stars can help better judge approx-imate age and distance, as explained in the chapter.

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2. Use a pushpin to make a small hole in the center of each star in your constellation and cut out thecircular paper pattern.

3. Using a hammer, put a nail-sized hole through the center of the metal end of the Pringles cancover. (sAFETY: Use caution hammering the nail. Adult supervision is recommended.)

4. Place your piece of circular black paper under the plastic lid of the potato chip can, put the lid onthe open end of the can, point the constellation drawing toward a light source, look through thehole in the metal end of the can, and see the star pattern as it would appear in the night sky.

Summary: stars are arranged in groups which we refer to as constellations. This activity empha-sizes selected star patterns visible in the night sky. It is hoped that a greater interest in specific con-stellations will lead to deeper investigation into the wonderment and ever-changing night skythroughout the year.

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Learning Outcomes- Define astronomical unit (AU).

- Distinguish between solar flares, solar prominences, and sunspots.

- Describe the moon in terms of temperature, atmosphere, gravity, and terrain.

- Identify the phases of the moon.

- Explain what causes a solar and lunar eclipse.

- Define comet.

- Explain the differences between an asteroid, meteoroid, meteor, and meteorite.

Important Terms

asteroid - a small rocky body orbiting the sun; usually found in the asteroid belt

astronomical unit (AU) - unit of measurement used to measure distances in our solar system

comet - a small, icy body orbiting the sun

meteor - a small streak of light; when a meteoroid enters the Earth’s atmosphere it becomes a meteor

meteorite - a meteor that enters Earth’s atmosphere and actually hits Earth’s surface

meteoroid - clump of dust or rock orbiting the sun

micrometeorite - very small dust-sized bits of matter

photosphere - thin shell of the sun’s outer layer

solar flares - short-lived high energy discharges from the sun

solar prominences - larger energy discharges from the sun that can be thousands of miles high and

last for months

solar system - the sun and the bodies that orbit around it

sunspots - darker, cooler areas of the sun

When you hear "solar system" what do you think of? most of us probably think of the planetswithin our solar system. some of us might think about the sun. These are good responses becausethey are part of our solar system. What is our solar system? Our solar system is the sun, the planetsand their satellites, asteroids, comets, and any celestial body that comes under the gravitational influ-ence of our sun. This gravitational influ-ence means that these bodies orbit thesun. The word solar means anything per-taining to or proceeding from the sun.so, the sun is the key feature of our solarsystem. Our solar system, however, isjust one of many in the universe. In2010, astronomers reported that approxi-mately 15% of the stars in the milky

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Way Galaxy may be part of systems like our solar system – and that is just within our galaxy. “Withbillions of stars out there, even narrowing the odds to 15% leaves a few hundred million systems thatmight be like ours,” said astronomer Andrew Gould.

THE SUNThe sun is the most important element of our solar system. Without its heat and light, the Earth

would be a lifeless, ice covered planet. On Earth, the sun sustains our lives, and it gives energy whichprovides food and oxygen. It stirs our atmosphere and initiates our weather.

The sun is a star. All other bodies of the solar system revolve around it. Because of this, the sun isthe point of reference for most facts about our solar system. When people talk about distances in oursolar system, they tell how far something is from the sun. For instance, the Earth is 93 million milesfrom the sun. Because distances of most planets from the sun are millions of miles away, scientistsuse a unit of measurement called the astronomical unit (AU) to measure distances within our solarsystem. Because we are most familiar with the distance from Earth to the sun, the distance of 93 mil-lion miles (149,668,992 km) is the start for measuring in astronomical units. The distance of 93 mil-lion miles equals 1 AU. The measurement of 2 AU equals 186 million miles, and so on. so, you maysay either, “The Earth is an average of 93 million miles from the sun,” or, “The average distance be-tween the sun and the Earth is 1 AU.” Venus, as another example, is about 0.7 AU from the sun. Howfar away is Neptune? It is about 30 AU from the sun. Try calculating how many miles that is if 1 AUequals 93 million miles. You are correct if your answer is about 3 billion miles (2.793 to be exact).

When talking about the size of planets, one often compares them to the size of the sun. The sun is300,000 times as massive as the Earth. If the sun were hollow, you could fit approximately 1 millionEarths inside it. Our solar system, our world, could not exist without the sun.

The sun is a medium-sized star composed of about 90% hydrogen, 9% helium, and minor amountsof several other elements. Its diameter is 864,000 miles (1,390,473 km). You could fit 100 Earthsacross the diameter of our sun. The temperature of the sun ranges from 7592° F (4,200° C or 4473 K)in its coolest regions to over 27,000,032° F (15 million degrees C or 15,000,273 K) at its center.

As just mentioned, the sun consists mostly of hydrogen and helium. The hydrogen is convertedinto helium by nuclear fusion. This process generates and releases the sun’s energy in all directions,all of the time. It is generally accepted that the sun is a giant thermonuclear reactor, releasing atremendous amount of energy.

The core of the sun is so hot that no solid or liquid molecules can exist. Virtually, all atoms remainin a plasma state. The energy released within the core has to make its way to the surface, atom byatom. It’s theorized if the sun’s fusion reaction were to suddenly halt, it would take more than100,000 years before any effect would show on the surface of the sun.

The very thin shell of the sun’s outer layer is called the photosphere. This is the part of the sunthat gives off light. It is also the visible surface that we see. This shellis composed mostly of hydrogen and helium, and is very hot. Its tem-perature is more than 10,000° F.

The outer layers of the sun indicate constant motion and violentactivity. solar disturbances occur all of the time. sometimes they lastfor less than a second, and other times they last for years. These solardisturbances are usually associated with sunspots. Sunspots aredarker, cooler areas of the sun. From these sunspots, solar flares andsolar prominences occur.

Solar flares are short-lived, high-energy discharges, that are po-tentially dangerous. They can harm satellites, ground systems, space- Sunspots

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craft, and astronauts. We monitor the sun’s activ-ity closely so we can react quickly when flaresoccur. The less dangerous electromagnetic radia-tion from a flare will reach Earth in less than 9minutes. The more dangerous high-energy parti-cles may take 15 minutes to 3 days to get here.space operators must be prepared to act quickly.

As explained in NAsA’s Radbelts website,“During the Apollo program, there were severalnear-misses between the astronauts walking onthe surface of the moon and a deadly solar stormevent. The Apollo 12 astronauts walked on themoon only a few short weeks after a major solarproton flare would have bathed the astronauts ina 100 rem blast of radiation. Another major flare

that occurred halfway between the Apollo 16 and Apollo 17 moonwalks would have had a much moredeadly outcome had it arrived while astronauts were outside their spacecraft playing golf. Within afew minutes, the astronauts would have been killed on the spot with an incredible 7000 rem blast ofradiation.”

Solar prominences are larger and longer lasting high-energy discharges. Prominences can reachthousands of miles and last for months.

On rare occasions here on Earth, we may experience an event known as a solar eclipse. This occursduring the daylight hours when the moon moves directly between the sun and the Earth, blocking thesun for a short time as it continues its orbit around the Earth. This is rare, however, because themoon’s orbital path around the Earth is tilted at about 5° compared to the orbital path of the Eartharound the sun. You will learn more about this when you read about lunar eclipses. (see associatedActivity Nine at the end of the chapter.)

THE MOONThe Earth has one moon and it is situated in an elliptical (oval-shaped)

orbit around the Earth. Because it is elliptical and not circular, the moon’sdistance from the Earth changes slightly. The distance varies from approx-imately 252,000 miles (405,555 km) at its farthest point to 221,000 miles(355,665 km) at its nearest point, with the average distance being close to240,000 miles (386,243 km). You could fit about 30 Earths between theEarth and the moon. While the Earth’s diameter is about 7,920 miles(12,746 km), Earth’s moon has a diameter of about 2,155 miles (3,468km), which is close to ¼ of the Earth’s diameter. If you could travel to the moon in a car at a speedof 65 miles per hour, you could reach the moon in about 154 days. The Apollo astronauts who trav-eled to the moon had to reach a speed of about 25,000 miles per hour to escape Earth’s gravitationalpull. They made it to the moon in about 3 days traveling at an average speed of about 3,418 miles(5,500 km) per hour. (see associated Activity Ten at the end of the chapter.)

The moon’s gravitational pull is weak compared to that of Earth’s; therefore, the weight of ob-jects on the moon would be different compared to Earth. The gravitational pull of the moon is 1/6that of Earth’s. This means, if someone weighs 90 pounds on Earth, the person would only weigh 15pounds on the moon. Divide your weight by 6 to determine how much you would weigh on themoon.

Due to this weaker gravitational pull, the moon has no atmosphere. The gravity of the moon istoo weak to trap any gases, such as oxygen, carbon dioxide, nitrogen, and so on. Because of this,

The Earth’s Moon

The Sun showing solar prominences

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there is no wind or air of any kind onthe moon. sound travels through air;therefore, there are no sounds on themoon. The astronauts who went to themoon during NAsA’s Apollo Programwere able to communicate due to theair in their spacesuits and their lunarlander.

While there are no oceans, lakes,streams, or polar ice caps on themoon, scientists had reason to believethat water ice might exist on the moondue to evidence from past unmannedlunar missions. scientists were excitedto find conclusive evidence of wateron the moon thanks to data obtainedfrom NAsA’s LCROss (Lunar CraterObservation and sensing satellite)mission. In 2009, the LCROss probe

collected and transmitted information about a plume of lunar dust and particles created by the impactof a two-ton rocket slamming into a lunar crater. The crater, which is visible from Earth and is namedCabeus, is permanently shadowed on the moon’s south pole. This is important because the tempera-ture of sunlit areas on the moon can reach 250° F (121° C), which means water would quickly evapo-rate, and the gases would easily escape into space due to the moon’s weak gravitational pull. Forwater to exist, it would need to be in the form of water ice, which would only be possible in a dark orshaded area on the moon, such as the crater Cabeus. The initial data from the LCROss mission re-vealed approximately 24 gallons of water. As for LCROss, it also slammed into the crater, asplanned, approximately 4 minutes after the rocket. Its hugely successful mission brings to light manymore questions such as, “How did the water ice get there?” “How much water ice is on the moon?”and “How could we use this resource to benefit human exploration of the moon?”

The moon consists mainly of solid rock covered with dust. This fine dust covers the entire surfaceof the moon. There are two theories on how the dust got there. some think the impact of meteoroidsstriking the surface pulverized lunar matter into dust, which settled to the surface slowly and evenly.Others think the dust is cosmic dust from space that the moon’s gravitational pull brought to the sur-face.

Primarily, the moon has two types of terrain, highlands and lowlands. The highlands are filledwith craters surrounded by mountains, and the lowlands are filled with craters that have been floodedwith molten lava and appear as dark areas called maria (Latin for sea).

The moon has many different kinds of rocks.We learned this from the lunar landings. moonbasalt is a dark gray rock with tiny holes fromwhich gas has escaped. It closely resemblesEarth basalt, but contains different mineral com-binations. On the moon, basaltic lava makes upthe dark, smooth surfaces of the lunar plains,which cover about half of the visible side of themoon.

Probably the most common rock on the moonis anorthosite. This rock is composed almost en-tirely of one mineral, feldspar. Anorthosite is The surface of the Earth’s Moon

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found in the highlands of the moon and shows upfrom Earth as the light areas of the moon.Anorthosite is rare on Earth, but is found inGreenland and is believed to be an ancient rock.

The moon rotates on its axis in the sameamount of time it takes to orbit the Earth (27days). Therefore, the same side of the moon(near side) always faces the Earth. One-half ofthe surface of the moon is illuminated by thesun, and the other half is in shadow. However,the amount of surface we see, the phase of themoon, depends on how much of the near side ofthe moon is in the sunlight. As the moon rotatesaround the Earth, its position relative to the sunchanges. As seen from the Earth, this means thata part of the surface of the moon that is inshadow is facing the Earth. When the moon is on the sideof the Earth nearer the sun, the moon is new. When it ison the opposite side of the Earth the moon is full. studythe pictures of the moon phases below to help you under-stand the shapes of the moon that are visible at differenttimes during the month. (see associated Activity Elevenat the end of the chapter.)

sometimes, the moon passes directly in Earth’sshadow. When this happens, part or all of the moon maynot be visible. This is called a lunar eclipse and occurswhen the sun, Earth, and moon line up in just the rightway. If the moon passes through the penumbra, the lightshadow cast by the Earth, the moon is partially eclipsed.If the moon passes through the umbra, the darkest part ofthe shadow cast by the Earth, the moon is totallyeclipsed. When the Earth’s shadow prevents the entiresurface facing the Earth to be blocked, it is called a total lunar eclipse. If the moon rotates aroundthe Earth each month, why doesn’t a lunar eclipse occur each month? It is because the moon is tiltedabout 5° in its orbital path around Earth compared to the orbital path of the Earth around the sun;therefore, the moon usually passes a little above or below the Earth. As explained at space.com, “Tovisualize, think of two Hula Hoops (one inside of the other) — one big and one small — floating onthe surface of a pool. Push the inner one down so that half of it is below the surface and half above.When the moon gets into the ecliptic — right at the surface of the pool — during its full phase, thena lunar eclipse occurs.”

A moon day lasts 27 Earth days; the time it takes to orbit the Earth. Daytime on the moon lastsabout 13-14 Earth days, one half the orbit time; the other half being nighttime.

Temperatures on the moon can rise above 250° F (121° C) during the day. Nighttime tempera-tures can go below -250° F (-157° C).

Although the Earth and stars are beautiful when observing them from the moon, the moon is aquiet, barren place with a black sky. To date, only twelve astronauts have walked on the moon’s sur-face as part of six Apollo missions between 1969 and 1972. Apollo 11 astronaut Buzz Aldrin de-scribed the moon as “magnificent desolation.” With no atmosphere, no running water, and extreme

Phases of the Moon

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temperatures, the moon is a gray, lifelessball orbiting the Earth. Without spacesuitsand life-supporting vehicles or habitats, hu-mans could not survive on our moon. (seeassociated Activity Twelve at the end of thechapter.)

OTHER BODIES Asteroids, comets, and meteoroids are

part of our solar system and therefore orbitaround the sun. Collectively, they arethought of as debris orbiting in space. Youmight wonder why they are important to us.Well, one reason is safety. space planners and space travelers need to consider these phenomena asthey prepare to go deeper into space. Let’s take a quick look at each of these individually and learn alittle more about them.

Asteroids are chunks of rock that range in size from particles of dust to some that are a few hun-dred miles across. most asteroids in our solar system travel in an orbit between mars and Jupiter.This area is known as the asteroid belt.

The first asteroid was discovered by an Italian astronomer, Guiseppe Piazi, in 1801. since thattime, more than 15,000 asteroids have been found and catalogued. scientists speculate that there areprobably millions more of them in our solar system. scientists know of more than 200 asteroidswhose orbits come close to our Earth and are capable of hitting us. However, the closest any havecome is about 100,000 miles (160,934 km).

spacecraft have flown through the asteroid belt and found that large distances separate asteroids.In October 1991, the asteroid known as Gaspra was visited by the Galileo spacecraft and became thefirst asteroid to have high-resolution images taken of it. Gaspra is composed of metal-rich silicatesand looks like a lumpy potato-shaped rock.

In 1997, the spacecraft Near Earth Asteroid Rendezvous (NEAR) made a high-speed, close en-counter with the asteroid mathilde. scientists found mathilde to be a carbon-rich asteroid. NEARwent on to encounter the asteroid Eros in 1999-2000. Eros had numerous boulders protruding abovethe surrounding surface.

Earth-based observations of asteroids continue, too. In may 2000,scientists observed the boulder Kleopatra with the 1,000 foot telescopeof the Arecibo Observatory. Kleopatra is a metallic, dog bone-shapedrock the size of the state of New Jersey.

A comet is described as a giant dirty snowball. It is irregularlyshaped with a tiny nucleus composed of frozen gases, water, dust, andicy lumps. Comets are usually a few miles across. Comets generallytravel around the outer regions of our solar system, but sometimes theyare bumped off their orbit and head toward the sun. As they approachthe sun, comets usually grow in size and brightness. As the cometmoves closer to the sun, the comet’s ice parts begin melting into agaseous and dusty tail that can extend for millions of miles.

sometimes, comets remain in their new orbits and repeat their jour-ney; therefore, scientists can sometimes predict future travel paths ofcomets. For instance, Halley’s Comet reappears every 76 years.

Asteroids

Comet

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English astronomer sir Edmund Halley first suggestedthat comets were members of our solar system. Afterstudying bright objects in the sky, he predicted the appear-ance of a comet in 1758.

When it appeared, the comet was named after him.Halley’s comet continues to make regular appearances inour skies. It last approached the sun in 1996.

Very small, dust-particle size bits of matter are calledmicrometeorites. From this size upward,these tiny parti-cles of dust and sand orbiting the sun are called mete-

oroids. meteoroids are usually leftover from a comet. If ameteoroid enters the Earth’s atmosphere it is called a me-

teor. If the meteor is large enough to penetrate our atmos-phere and actually hit the surface of the Earth it is called a meteorite.

meteorites are not that common, but they have occurred. However, meteors are very common.Friction causes a meteor to heat and glow and begin to disintegrate leaving a trail of luminous mat-ter. When there are many meteors seen in the sky within a period of an hour, it is called a meteorshower. meteor showers are also referred to as shooting stars. They can be seen on just about anynight if you get out in the country away from the city lights.

meteorites are the pieces of matter that remain when debris does not burn up completely as itpasses through the atmosphere and lands on the surface of the planet. scientists believe many mete-orites hit the Earth each year, but it is rare to actually see it happen. most meteorites are basketball-size or smaller, but larger pieces can and do impact the surface of the Earth. some meteorites aresmall pieces of an asteroid; others have proved to be material blasted off the surface of the moon fol-lowing an impact on its surface. Other meteorites have been determined to originate on mars.

The recent recovery of a carbonaceous chondrite meteorite from the Yukon has excited scientistswho say that its very primitive composition and pristine condition may tell us what the initial materi-als were like that went into making up the Earth, moon, and sun. Only about two percent of meteror-ites are carbonaceous chondrites containing many forms of carbon and organics, the basic buildingblocks of life. This type of meterorite is easily broken down during entry into the Earth’s atmos-phere, so recovery is quite rare. (see associated Activity Thriteen at the end of the chapter.)

SummaryThe sun is a star and is the most important element of our solar system. The sun releases a

tremendous amount of energy in the form of heat and light, which is essential for life on Earth. Themoon, on the other hand, does not produce heat or light. Its environment is very different fromEarth’s, and without spacesuits and life-supporting vehicles or habitats, humans could not survive onour moon.

Our solar system also includes comets, meteoroids, and asteroids. After reading detailed informa-tion about these objects, you should be able to explain how they are different from one another.

When thinking about our solar system, you probably immediately think of planets. In the lastchapter, we will visit each of the planets in our solar system.

Meteor shower

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33Activity Nine - Build a Solar CookerPurpose: This is the practical way to show how energy from the sun can be used.

Materials: shoe box, aluminum foil, plastic wrap, a skewer, and some hot dogs

Procedure:1. Line the shoe box with the foil.2. Insert a skewer through one of the short sides.3. Insert the skewer through a hot dog (lengthwise) and then stick the skewer into the other short side

of the box.4. Cover with the plastic wrap.5. Place the solar cooker in sunlight and let the sun cook your lunch. You could try baking cookies

from refrigerated cookie dough, as well.

Summary: The solar cooker uses sunlight as its energy source. The aluminum foil helps keep thelight and heat from the sun in the cooking area, increasing its intensity. The plastic wrap over thetop allows the sunlight to enter the box, but helps prevent heat from escaping. The temperature in-side the solar cooker then becomes hot enough to heat the hot dog. A discussion of how solar energycan be used in our country would be beneficial at this time.

Activity Ten - Earth-Moon DistancePurpose: This activity will give both a visual and mathematical comparison of the distance to themoon from the Earth using scale models to represent the actual objects.

Materials: world globe (important that the globe is 12 inches in diameter), tennis ball, string (atleast 30 feet long), reference book or internet site (as noted below), measuring tape, and calculator orpencil/paper for calculators

Procedure: 1. With the tennis ball representing the moon, ask students to place the tennis ball at a distance from

the globe that represents how far the moon is from the Earth. (Use the information found on page28 that states that you could fit about 30 Earths between the Earth and the moon.) This will be avisual representation of the distance from the Earth to the moon.

2. Next, as a mathematical representation of the distance, and a way to actually measure the scaleddistance, ask students to determine the circumference of the Earth by consulting a reference bookor using the internet, or use the summary information on next page. Using this circumference, thestudents should use the information on page 28 that tells that the distance from the Earth to themoon is about 240,000 miles and determine how many times the circumference of the Earth itwould take to measure the distance from the Earth to the moon. To do this, the students should di-vide the distance to the moon by the Earth’s circumference. (The summary will give the mathe-matical outcome.)

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Activity Eleven - Seeing the MoonPurpose: Demonstrate why we see different portions of the moon (phases of the moon) illuminatedin the sky due to light and shadows.

Materials: a dark room, a bright light source (a table lamp), a small ball (tennis or baseball), andthe demonstrator (a person doing the demonstration for the others)

Procedure:1. Hold the ball at arm’s length toward the bright lamp. 2. Ensure the room is dark except for the table lamp. With the lamp representing the sun, the head of

the demonstrator becomes the Earth, and the ball is the moon.3. The demonstrator should stand in place; slowly turning to the left so that the ball in the out-

stretched hand moves in a complete circle. Observers will be able to see the changing phases ofthe moon on the ball.

Summary: As shown in the illustration of the phases of the moon on page 30, as the moon makesits 27-day orbit of the Earth, the amount of sunlight that reaches the moon when it is not in theEarth’s shadow determines the surface of the moon that can be seen from Earth. The phases of themoon are said to determine many factors on Earth, such as are found in reference books, called Al-manacs.

3. Compare the earlier visual idea of the distance between the Earth and the moon with measureddistance based on the Earth’s circumference. To do this, wrap the string around the globe 9.5times. Then hold one end of the string at the surface of the Earth and stretch the string across theclassroom. The other end of the string represents the distance of the Earth to the moon. measurethe distance.

Summary: The Earth’s circumference is about 25,000 miles. The distance from the Earth to themoon is about 240,000 miles. When you divide the distance between the Earth and the moon by thecircumference of the Earth you get 9.6 or, averaged 9.5. Using this scale, the distance from themodel Earth to the model moon should be 9.5 times the circumference of the model Earth, or about30 Earths away, as calculated in the equation below. mathematically:

C = pdC = 3.14 x 12”C = 37.68”Then, 37.68” x 9.5 = 357.96” or 29.83 ft (about 30 ft, or 30 Earths)

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Activity Twelve - Lost on the Moon - SurvivalPurpose: This activity accomplishes several things: the analysis of the moon’s atmosphere, theevaluation of the importance of available materials while on the moon, the identification of similari-ties and differences between the Earth and moon, the use of critical thinking skills, and the promo-tion of team building.

Background: Your spaceship has just crash-landed on the dark side of the moon. You were sched-uled to rendezvous with your mother ship 200 miles away, on the lighted surface of the moon, butthe rough landing has destroyed your ship and ruined all but the 15 items listed below.

since your crew’s survival depends upon reaching the mother ship, you must choose the most criti-cal items available for the 200-mile trek across the moon’s surface. You must determine the "priority"of survival items and list them. Back on Earth, NAsA would have given you their priority, but no con-tact can be made. The decision is yours. How would your team skills compare to those of the NAsAhome team? It’s fun to compare your answers with those of NAsA and other teams.

Materials: checklist of items provided, a pencil or pen

Procedure:1. Divide the group into small teams.2. Hand out a copy of the problem or read it to the teams.3. Have students rank the 15 items in their order of priority.4. After the students are done, have them discuss and justify their rankings to the other teams.5. show the students the NAsA rankings.6. Calculate the error points for individuals and teams, using the NAsA ranking on the next page.Calculate error points for the absolute difference between the NAsA ranking and the individualor group ranking. scoring: 0-26 = Excellent

27-32 = Good33-45 = Fair

46-112 = still lost on the moon

Summary: An understanding of the lunar environment and an ability to critically think and discussideas are necessary to make good judgments regarding the importance of the items on the survival list.Working as a team to make these selections is beneficial in making good decisions.

ITEMS NASA RANKING YOUR RANKING ERROR POINTS ERROR POINTSGROUPRANKING 1 Box of matches2 Food concentrate3 50' of nylon rope4 Parachute silk5 Solar powered heating unit 6 Two 45 caliber pistols7 One case of Pet milk8 Stellar map9 Two 100-pound oxygen tanks

10 Self-inflating life rafts11 Magnetic compass12 Five gallons of water13 Signal Flares

TOTALS

14 First aid kit containing injection needles15 Solar powered FM transceiver

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Lost on the Moon

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Activity Thirteen - Meteoroids and Space DebrisPurpose: Demonstrate the penetrating power of a projectile with a small mass and how it differs de-

pending on the velocity (speed and direction).

Materials: two or three raw potatoes (depending on group size), several large diameter plastic

straws (Each person should get a chance to participate.)

Procedure:

1. Hold the raw potato in one hand.

2. While grasping the straw with the other hand, stab the potato with a quick sharp motion. The straw

should completely penetrate the potato. CAUTION - Don’t strike your other hand.

3. Again, hold the potato and now stab it with the straw using a slow push. The straw should bend

instead of penetrating the potato.

Summary: Even a small mass can penetrate many things if its velocity is high enough. This was

demonstrated by the straw penetrating the potato. meteoroids and space debris traveling at high

speeds pose significant hazards, particularly to space walking astronauts. spacesuit material is made

of special layers of materials to help protect astronauts from meteoroids and small space debris.

Learning Outcomes

- Define planet.

- state basic facts about the planets in our solar system.

- Define and identify dwarf planets.

Officially, our solar system contains eight planets. most of us can probably name them, and aresomewhat familiar with them. You may be thinking, “Wait. I thought there were nine planets.” Thatwas true until 2006 when the International Astronomical Union (IAU), the governing body of astron-omy, revised the definition of “planet,” which left Pluto out of the traditional planet category.

The IAU’s definition of planet is "a celestial body that (a) is in orbit around the sun, (b) has suffi-cient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilib-rium (nearly round) shape, and (c) has cleared the neighborhood around its orbit." Let’s take a fewmoments and look at some interesting facts about each planet, as well as Pluto. We’ll start with mer-cury and go in order of each planet’s distance from the sun.

Mercurymercury is the closest planet to the sun, yet it is the most difficult

to see because of the sun’s glare on it. (Don’t look for mercury whilethe sun is in the sky. It could damage your eyes.) mercury is slightlylarger than the Earth’s moon and is the smallest of the eight planets.

mercury is only 36 million miles (0.39 AU) from the sun and re-volves around the sun every 88 days. It has a very elliptical orbit, andit moves about 30 miles (48 km) every second. mercury rotates veryslowly, taking 59 Earth days to rotate on its axis.

mercury, which has nomoons, has a rocky,crusty surface with manycraters resembling the craters of the Earth’s moon. manyof these craters were formed when rocks crashed into theplanet. mercury also has many lava flows and quakefaults on its surface. These craters, flows, and faults haveshaped the surface of the planet.

Except for small amounts of helium and hydrogen,mercury has no atmosphere. scientists believe that mer-cury has an iron core that extends through most of theplanet. mercury has significant temperature differences.Its daytime temperature reaches 800° F (427° C), whileits nighttime temperatures reach -300° F (184° C).

Pictures of mercury’s surface were first taken from

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The surface of Mercury

as seen from Mariner 10

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Mercury

the Mariner 10 spacecraft that made flybys in 1974 and 1975, photographing about 45% of the sur-face of mercury. The pictures displayed mercury’s many craters and loose, porous soil. It also gaveindications that ice existed at its poles, in deep craters, where the sun could not melt it. In the threeMariner 10 flybys, it was discovered that both a thin atmosphere and magnetic field existed.

In order to learn more about mercury, NAsA created the mEssENGER Program.Launched onAugust 2, 2004, mEssENGER conducted its first of three flybys of mercury on January 14, 2008.Information collected from mEssENGER’s three flybys along with the key images taken fromMariner 10 helped to produce the first global map of mercury in December of 2009. Beginning anorbital mission in 2011, mEssENGER is the first spacecraft to orbit mercury. Through the mEs-sENGER Program, scientists will gain valuable information to better understand mercury’s geologi-cal history, extreme density, magnetic field, core, poles, and exosphere.

VenusNext, is Venus. It is the closest planet to Earth in both dis-

tance and size and is often referred to as Earth’s sister. Venus is67 million miles (0.7 AU) from the sun. It takes 225 days to re-volve around the sun. It is a very hot planet with temperatures inexcess of 850° F (454° C). In fact, Venus is the hottest planet inthe solar system.

Even with the heat, Venus is covered with clouds. Theseclouds are made of water vapor and sulfuric acid, and they rotateat a different rate than the planet. These clouds rotate every fourdays; much faster than the 243 Earth days it takes for Venus torotate on its axis. By the way, Venus is the only known planet to rotate in a clockwise manner.

The atmosphere is 96% carbon dioxide and 4% nitrogen. There are also small amounts of water,oxygen, and sulfur. scientists believe volcanic activity is responsible for the sulfur found in the at-mosphere. Because of this thick layer of carbon dioxide and the clouds, the heat cannot escape.Therefore, there is very little temperature change on Venus.

The surface of Venus is a relatively smooth, hot desert. It does have some highlands and craters,too. Venus is the easiest planet to see at night and is the brightest of all. You can even see it in thedaytime if you know where to look. since it is the brightest planet that can be seen from Earth,Venus is referred to as the Evening star. Venus has no moons.

since Venus is the closest planet to Earth, it is also the most visited by our spacecraft. Mariner 2,5, and 10 visited Venus, as did Pioneer 1 and 2. The UssR’s Venera 9 and 10 also visited Venus.

The Magellan spacecraft, launched in may of 1989 aboard the space shuttle Atlantis, was sent toorbit Venus from 1990-1994. It collected radar images and was able to map more than 98% of theplanet’s surface. As a result of the mission, it was verified that volcanic materials cover most ofVenus.

Venus continues to be visited by spacecraft. The Venus Express, a European space Agency space-craft that was launched in November of 2005, is scheduled to remain operational until 2012. Also, inthe summer of 2010, Japan launched the Venus Climate Orbiter “Planet-C,” nicknamed “Akatsuki,”

which means “dawn.”Akatsuki should reveal much detail about the climate and atmosphere of Venus.As explained by Japan Aerospace Exploration Agency (JAXA), “The Venus Climate Orbiter ‘AKAT-sUKI’ (PLANET-C) is the world’s first planetary meteorological observation satellite to unveil themysteries of wind on Venus. It will explore the mechanism of the Venus climate by observing the at-mospheric movement and cloud formation process.” In learning about Venus, scientists also believethat they will develop a deeper understanding of Earth’s environment: past, present, and future.

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Venus

EarthAs far as we know, Earth is the only planet that sustains life.

Therefore, it is a unique planet. Earth is approximately 1 AU (93million miles) from the sun, and it takes the planet about 365days to make one revolution around the sun, which is one Earthyear. Remember that the average distance from the Earth to thesun is a straight line from the Earth to the sun. The average dis-tance that the Earth travels in its orbit around the sun (circumfer-ence of Earth’s orbit) is about 584 million miles (939,856,896km). If the Earth has to travel about 584 million miles to make acomplete orbit around the sun, and it takes about 365 days to dothis, can you figure out about how fast the Earth is travelingaround the sun (not taking into account other factors such asEarth’s wobble, one’s location on Earth, etc.)? You arecorrect if you calculated about 66,700 mph or 19 milesper second.

Besides speeding around the sun, the Earth alsomoves by rotating on its axis. One day on Earth is thetime it takes for the Earth to spin once on its axis, whichis 24 hours. Because the Earth spins on its axis onceevery 24 hours, we experience day and night. If Earth’scircumference at the equator is about 24,901 miles(40,074 km), and it takes 24 hours for a point on Earth’sequator to make one complete rotation, about how fast isthe Earth spinning on its axis? You are correct if you cal-culated a little over 1,000 miles per hour (or a little over a quarter of a mile per second).

Earth has four seasons because of the tilt of the Earth on its axis. Earth is tilted about 23.5° on itsaxis. Because of this, different parts of the Earth receive different amounts of direct sunlight at differ-ent times of the year. For example, when the northern hemisphere experiences summer, the northernhemisphere is tilted more towards the sun, and the rays of the sun hit the northern hemisphere at amore direct angle. It, therefore, is not the distance between the Earth and the sun that creates the sea-sons, but rather the tilt of the Earth on its axis.

Twice during the year, Earth experiences a solstice. A solstice occurs when the sun is at its highestor lowest point in the sky. This occurs in the summer and winter. The summer solstice for the North-ern Hemisphere occurs about June 21 and the winter solstice occurs around December 21. After thesummer solstice, the hours we receive daylight slowly get fewer and fewer until we reach the wintersolstice, which is the shortest day of the year in terms of daylight. After the winter solstice, theamount of daylight hours slowly increases until the summer solstice, which is the longest day of theyear in terms of daylight hours.

Twice a year, the Earth experiences an equinox. An equinox occurs when the amount of daylighthours and nighttime hours are about the same due to the position of Earth in its orbit around the sun,which causes the concentration of direct sunlight to be closest to the equator. The vernal equinox forthe Northern Hemisphere occurs about march 21 and marks the beginning of spring. The days willcontinue to get longer in terms of daylight hours up until the summer solstice, which marks the begin-ning of summer. The autumnal equinox occurs about september 21 and marks the beginning of fall.The days will continue to get shorter in terms of daylight hours and cooler as the winter solstice drawsnear.

Our atmosphere contains 78% nitrogen and 21% oxygen, with small amounts of argon, carbon-

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Earth

Tilt and seasons

41

dioxide, neon, helium, ozone, and hydrogen. This atmosphere provides the oxygen that we breatheand keeps the temperature of water as liquid, so that life is possible. Our atmosphere also acts like aprotective blanket. It contains clouds, and these clouds, along with the chemical composition of the at-mosphere, help absorb some of the sun’s radiation.

A common question people have about Earth is, “Why is the sky blue?” NAsA has an explanationthat is fairly easy to understand. “The light from the sun looks white, but it is really made up of all thecolors of the rainbow. When white light shines through a prism, the light is separated into all its col-ors. Like energy passing through the ocean, light energy travels in waves, too. some light travels inshort, choppy waves. Other light travels in long, lazy waves. Blue light waves are shorter than redlight waves. sunlight reaches Earth’s atmosphere and is scattered in all directions by all the gases andparticles in the air. Blue light is scattered in all directions by the tiny molecules of air in Earth’s at-mosphere. Blue is scattered more than other colors because it travels as shorter, smaller waves. This iswhy we see a blue sky most of the time.”

The surface of our planet is covered with over 70% water, with the Pacific Ocean accounting forover 50% all by itself. Orbiting Earth is its one moon, as discussed in the previous chapter. Themoon’s gravity pulls on Earth and Earth’s gravity pulls on the moon. This mutual attraction is strongenough to pull the water in the Earth’s oceans slightly towards the moon, creating tides.

While 70% of Earth is covered in water, the remaining 30% is covered with various land features.The Earth has anywhere from smooth pastures, to plateaus and small hills, to tremendous mountains. Wehave lush forests and barren deserts. Our planet sustains not only human life, but plant life and animallife, too. From a variety of life forms to landscapes to climates, Earth is an interesting planet to study.

MarsOf all of the planets, mars probably fascinates us the most. Over

the years, it has been the most publicized in books and movies, andjust about everyone knows it as the Red Planet. This is due to itsred color which can be seen even with the naked eye. This color isdue to the rock and dust covering the surface of mars. It has beenanalyzed and found to have a high iron content, so it has a rustylook. Because of the decreased gravitational pull of mars, the blow-ing dust on mars rises easily, which also contributes to the atmos-phere’s reddish pink appearance.

mars is about half as big as Earth and has about 1/9 the mass ofthe Earth. Because its gravitational pull is about 1/3 that of Earth’s,objects weigh only about 1/3 of what they weigh on Earth. For ex-ample, if something weighed 66 pounds on Earth, it would weighabout 22 pounds on mars.

mars has farther to travel around the sun than Earth, but it takes about the same time as Earth torotate once on its axis. The length of a martian day is about the same as an Earth day at 24 hours 37minutes. A martian year is about 687 Earth days, which is about twice as long as an Earth year. Howold are you on mars? Divide your age by two for a close estimate.

Although the atmosphere of mars is much less dense than Earth’s, mars has an atmosphere thatsupports a weather system. The atmosphere, which consists of 95% carbon dioxide, 3% nitrogen andtraces of oxygen, carbon monoxide, and water, includes clouds and winds. Blowing dust stormsoccur periodically over the surface. Daytime surface temperatures near the equator on mars canreach about 70° F (21° C), while nighttime temperatures can dip to -130° F (-90° C). The averageplanet temperature is about - 80° F (-62° C). Although a cold planet overall, mars does have fourseasons due to the tilt of its axis, which is about 25°.

Mars

The surface of mars is covered with deserts, high mountains, deepcraters, valleys, and huge volcanoes. One of mars’s volcanoes, Olympusmons, is the highest known mountain in our solar system. It is about 370miles (595 km) across and 17 miles (27 km) high. (That is much taller thanmt. Everest which is about 5.5 miles high.) The largest known canyon inour solar system is mars’s Valles marineras. It stretches over about 1/5 thecircumference of mars, which is about 2,490 miles (4,007 km). If placed onthe continental United states, it would stretch from the west coast to the eastcoast. some parts of the canyon reach between four and five miles deep,compared to the Grand Canyon’s lowest depth of about one mile (1.6 km).

Another geological feature on mars is its polar ice caps. The polarice caps are made of frozen carbon dioxide, or dry ice, and water ice.The water ice is located below frozen carbon dioxide. The ice capswax (get bigger) and wane (shrink) with the seasons, waxing in win-ter and waning in the summer.

Orbiting mars are its two small moons, Phobos and Deimos.Named after Greek mythological figures, their names translate tofear and panic. scientists believe that these potato-shaped moons areactually asteroids that got captured by the gravitational pull of mars. Phobos, slightly larger thanDeimos, orbits closer to its planet than any other moon in our solar system, orbiting about 3,700miles (5,955 km) from the planet. It is believed that in millions of years, Phobos might crash intomars or break apart before it reaches mars, resulting in smaller pieces of rocks orbiting mars.

mars’s average distance from the sun is approximately 141.6 million miles, which is about 1.5AU. If you could drive to mars when Earth and mars are closest together, it would take about 66.5years traveling at 60 mph. Depending on their positions in their orbits, the closest distance betweenEarth and mars is about 35 million miles (56,327,040 km), but they can reach a maximum distanceof about 250 million miles (402,336,000 km). The distance between the two planets is critical toplanning missions to mars.

In the mid to late 1960s, the Mariner spacecraft made flybys of mars and took lots of photos. Pic-tures revealed mars’s surface to be like the Earth’s moon. Then in the mid 1970s another probe,Viking I, touched down on mars. The primary mission of Viking I and Viking 2 was to determine iflife ever existed on mars. Unfortunately, the experiments were inconclusive even though more water

was found on mars than had been expected.In July 1997, the space probe called the mars Pathfinder

landed on mars. The next day the Pathfinder’s rover, SojournerTruth, began its exploration of the planet. The Sojourner was twofeet long and one foot tall. It studied the surface, analyzed thesoil and rocks, and conducted scientific experiments on mars.

Two other rovers, Spirit and Opportunity, landed on the mar-tian surface in January 2004. Their missions were extended forthe fifth time in 2007. These rovers were able to study the geol-ogy of mars, which provides great insight into explanations ofthe past and present environment of mars. NAsA reported, “Op-portunity has returned dramatic evidence that its area of mars

stayed wet for an extended period of time long ago, with conditions that could have been suitable forsustaining microbial life. spirit has found evidence in the region it is exploring that water in someform has altered the mineral composition of some soils and rocks.” Originally scheduled for a 90-day mission, these rovers were still operating in 2010.

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Sojourner Truth

Valles Marineras

Olympus Mons

43

In July of 2008, a NAsA spacecraft, the Phoenix Mars Lander, confirmed water on mars.Phoenix had a scoop device that was able to dig up subsurface soil samples. It was also able to heatthe samples and analyze them. “We have water,” said William Boynton of the University of Arizona,lead scientist for the Thermal and Evolved-Gas Analyzer, or TEGA. “We’ve seen evidence for thiswater ice before in observations by the mars Odyssey orbiter and in disappearing chunks observedby Phoenix last month, but this is the first time martian water has been touched and tasted.” Phoenix

landed on mars on may 25, 2008 in the northern polar plains and operated for five months, twomonths longer than scheduled. Its mission not only confirmed water ice on mars, but also providedmore insight into its climate, soil, and history.

supporting both the Spirit and Opportunity rovers and the Phoenix lander is NAsA’s marsOdyssey orbiter. Along with detecting water ice on mars, the orbiter was launched in 2001 to mapthe chemical elements on mars and collect radiation data, the Johnson Propulsion Laboratory (JPL)in Pasadena, CA reported that “infrared mapping showed that a mineral called olivine is widespread.This indicated the environment has been quite dry, because water exposure alters olivine into otherminerals.” An instrument on the mars Odyssey found that the mars’s radiation level is two to threetimes higher than that around Earth. In addition to these accomplishments, the mars Odyssey helpedstudy landing sites for Spirit, Opportunity, and Phoenix and provided communication relay supportto them.

Other spacecraft have, are, and will study mars in order to gain more insight into our neighbor,which some people believe may have the right ingredients for life. Next to Earth, it certainly has themost favorable conditions of any of the other planets in our solar system. mars is the last in a line ofwhat is considered the inner terrestrial planets.

JupiterJupiter is the first in the line of the outer, gaseous planets in our

solar system. It is about 483.6 million miles from the sun, whichis about 5.2 AU. (Remember, 1 AU equals 93 million miles.) Atits closest distance to Earth, Jupiter is about 500 million miles(804,672,000 km) away. so, if you drove about 60 mph, it wouldtake you hundreds of years, actually close to 1,000 years, to reachJupiter.

Jupiter is the largest planet in our solar system. Its diameter isabout 88,700 miles (142,749 km). About 11 Earths could fitacross the diameter of Jupiter. Jupiter is so big that if it wereempty, every planet in our solar system could fit inside it. If you were only putting Earths inside it, itcould hold about 1,320 Earths. Even though Jupiter is the largest planet in our solar system, it stillisn’t as big as the sun. About 915 Jupiters could fit inside the sun.

As far as mass, Jupiter’s mass is so massive that it would take about 318 Earths to equal the massof Jupiter. Although it has a huge mass, it has a low density because it is composed primarily of hy-drogen, the lightest element. Jupiter’s large size, huge mass, and low density create a gravitationalpull on Jupiter that is about 2.5 times that of Earth’s. so, an object weighing 100 pounds on Earthwould weigh about 250 pounds on Jupiter.

A couple of other facts about Jupiter involve its revolution around the sun, its rotation on its axis,and its temperatures. Jupiter revolves in almost 12 Earth years. Even though Jupiter is huge, it ro-tates on its axis very quickly, about every ten hours. This causes a flattening effect at the poles and abulging effect at the equator. This fast rotation also enhances the weather patterns on Jupiter. It cre-ates high winds and giant storms on Jupiter, where the temperature ranges from over 60,000° F

Jupiter

(33,316° C) at its center, to -220° F (-140° C) at the upper cloud layers.Jupiter is a gas giant. Hydrogen is the most prominent gas (about 90%), followed by helium,

methane, and ammonia. The outer core of Jupiter is composed of liquid hydrogen and helium, andthese mix with the gaseous atmosphere to form belts of clouds. These belts are very colorful, butchange rapidly due to the high winds associated with the quick rotation of the planet. These beltsmake Jupiter look like a striped ball with a giant red spot in the lower half. The Giant Red spot is adistinguishing feature of Jupiter. This spot is a giant storm that is 30,000 miles (48,280 km) long and10,000 miles (16,093 km) wide.

A great deal of atmospheric activity on Jupiter is similar to that of Earth. However, Jupiter’sstorms seem to be powered by the planet itself rather than by the sun, as they are on Earth. Jupiter’shighly-compressed hydrogen at its center causes the planet to emit almost 70 percent more heat thanit absorbs from the sun. This leads scientists to speculate that the source of Jupiter’s stormy turbu-lence is the planet itself.

To learn more about Jupiter and its moons, spacecraft havebeen launched toward this gas giant since as early as the 1970s.The Pioneer probes, launched in the 1970s, were the first tovisit Jupiter. They discovered that the banded structure of theatmosphere was not present near the poles. The poles had athick blue-sky atmosphere. Detailed studies showed rapid mo-tions among the clouds and changes in the wind speeds. Begin-ning in 1979, Voyager probes were launched to study the outerplanets. In 1979, Voyager 1 discovered rings around Jupiter.Jupiter’s rings are dark and difficult to see, unlike those of sat-urn. It was the spacecraft Galileo that revealed that the ringsaround Jupiter are formed by dust.

The Galileo mission was launched in October 1989 with the help of the space shuttle Atlantis. Itsmission was to study Jupiter’s atmosphere and moons. After flybys of Earth and Venus, it capturedthe first close-up picture of an asteroid in 1991 on its way to Jupiter. It also discovered the firstknown asteroid to have a moon, which was named Dactyl. It observed the comet shoemaker-Levycrash into Jupiter in 1994. Galileo began exploring Jupiter and its moons in 1995. After several ex-tensions of its mission, Galileo’s journey finally came to an end on sept. 21, 2003 after disintegrat-ing in Jupiter’s atmosphere. Galileo provided about 14,000 pictures and returned importantinformation about Jupiter and its moons.

As of January 2009, Jupiter had 49 officially recognized moons with 14 other moons still beingreviewed for “official” status. Ganymede, Callisto, Io, and Europa are the four largest moons ofJupiter. These four are called the Galilean moons, named after their human 1610 discoverer, Galileo.

The icy Ganymede moon is the largest moon in our solar system. It is larger than the planet mer-cury, but not quite as big as mars. NAsA’s Galileo spacecraft indicated the presence of a magneticfield, making Ganymede the only known moon to have one. In 1996, the Hubble Space Telescope

detected a thin atmosphere containing oxygen, but the atmosphere is too thin to support life. Callisto is covered with craters, and, in 1999, the Galileo spacecraft detected

a thin atmosphere of carbon dioxide. Io also has a thin atmosphere, and it has active volcanoes that eject sulfuric

acid. A NAsA reference describes Io as “a giant pizza covered with meltedcheese and splotches of tomato and ripe olives; Io is the most volcanically activebody in the solar system.” NAsA’s Galileo spacecraft revealed that the volcanicactivity on Io is 100 times greater than Earth’s. With the exception of the vol-

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Galileo Spacecraft

Io

45

canic areas, Io has a very cold surface temperature. Europa appears to be the smoothest celestial body in our solar system and has a weak atmosphere.

“Europa’s oxygen atmosphere is so tenuous that its surface pressure is barely one hundred billionththat of the Earth,” said Principal Investigator Doyle Hall, of Johns Hopkins. "If all the oxygen onEuropa were compressed to the surface pressure of Earth’s atmosphere, it would fill only about adozen Houston Astrodomes. It is truly amazing that the Hubble Space Telescope can detect such atenuous trace of gas so far away." It is thought that there is a liquid ocean under Europa’s icy surface.Based on the information returned from Galileo, it could have two times as much water as all of theoceans on Earth. Could organisms exist in that ocean?

Other outer planet spacecraft, such as Ulysses, Cassini-Huygens, and New Horizons, have flownby Jupiter on their way to other destinations. The next Jupiter-specific mission will be Juno which isscheduled to launch in 2011 and arrive at Jupiter in 2016. As part of NAsA’s New Frontiers mis-sions, this polar orbiter will study Jupiter’s atmosphere, magnetic field, inner structure, and polarmagnetosphere.

SaturnAbout 887 million miles (or 9.5 AU) from the sun, saturn

is the sixth planet in our solar system and second in the lineof outer, gaseous planets. Its diameter is about 74, 898 miles(120,537 km) across, meaning that about 9.5 Earths could fitacross it. As the second largest planet in our solar system,saturn could hold about 764 Earths inside it. saturn, how-ever, is the only planet in our solar system that is less densethan water. This means saturn could actually float in a bodyof water, if the body of water was large enough to hold sat-urn. Objects weigh close to what they weigh here on Earth as the gravitational pull on saturn isabout 1.08 times that on Earth. so, if an object weighed 100 pounds on Earth, it would weigh 108pounds on saturn.

Like Jupiter, saturn rotates at a very fast 10 hours. However, it takes over 29 years to revolvearound the sun. Also like Jupiter, the combination of fast rotation and gaseous and liquid atmospherecreates very strong winds, clouds, and storms. The winds of saturn have been known to reach 1,100miles per hour (1770 km).

When we think of saturn, we think of its rings. The rings are easily the most recognizable fea-tures of saturn. Through a telescope, the rings are spectacular. They are made of ice chunks, dust,and rocks ranging from tiny particles to large boulders, or the size of grains of sugar to houses.The main rings are made up of hundreds of narrow ringlets. The entire ring system is about onemile thick and extends about 250,000 miles (402,336 km) from the planet. There are seven distinctrings, each designated by a letter ranging from A to G, around saturn. The first five were discov-ered by Galileo in 1610, and the final two lettered rings were discovered by the Pioneer space-craft. The Jet Propulsion Laboratory (JPL) and NAsA also report that “there are also several otherfaint unnamed rings made up of very fine icy particles.”

The planet itself has an icy rock core surrounded by metallic hydrogen with an outer layer of hy-drogen and helium. The hydrogen and helium are mainly liquid and turn to gas as they get to theouter surface.

Being 9.5 AU from the sun, the temperatures of saturn do not vary as much as many of the otherplanets. During the day it gets up to 130° F (54° C) and at night, down to -330° F (-201° C).

Pioneer and Voyager passed by saturn in the late 1970s and early 1980s and produced much in-

Saturn

formation about the planet. For instance, in was found that saturn’s outermost region contained itsatmosphere and cloud layers. saturn’s three main cloud layers are thought to consist of (from topdown) ammonia ice, ammonia hydrosulfide ice, and water ice.

To date, 62 moons have been identified orbiting saturn, but only 53 of them have been named sofar. Titan, one of saturn’s moons, is currently the only moon known to have clouds and a thick at-mosphere. Its atmosphere is made up of about 95% nitrogen and 3-5% methane, along with somesmall amounts of other compounds. It has an orange, hazy sky, and its surface temperature is about -289° F (-178° C). Its seasons, although all extremely cold, last about 7 years each.

We have learned, and continue to learn, a great deal about saturn and its moons due to theCassini-Huygens mission, a joint mission between the European space Agency, the Italian spaceAgency, and NAsA. Launched in 1997, the spacecraft arrived at saturn in 2004. The Cassini space-craft did gravity-assist flybys of Venus and Earth, and performed a flyby of Jupiter as it traveled tosaturn at a speed of 70,700 mph. (If you drove 60 mph using the same path that Cassini took to getto Jupiter, about 2 billion miles, it would take you 5,600 years.) scheduled to end in 2008, the proj-ect received two extensions, of which the second extension will keep its missiongoing until 2017.

In January 2005, the Huygens probe, which was bolted to the Cassini orbiter,detached from the Cassini orbiter and landed on Titan. This is the first time aprobe landed on a celestial body in the outer solar system, and Titan is an interest-ing moon to study. NAsA reported that “Huygens captured the most attention forproviding the first view from inside Titan’s atmosphere and on its surface. Thepictures of drainage channels and pebble-sized ice blocks surprised scientists withthe extent of the moon’s similarity to Earth. They showed evidence of erosionfrom methane and ethane rain. Combining these images with detections of methane and other gasesemanating from the surface, scientists came to believe Titan had a hydrologic cycle similar toEarth’s, though Titan’s cycle depends on methane and ethane rather than water. Titan is the onlyother body in the solar system, other than Earth, believed to have an active hydrologic cycle, and thatis known to have stable liquid on its surface.”

Remember, this liquid is not water; it is mostly methane, which, like water, can take the form of agas, liquid, and solid. NAsA and JPL’s Cassini Web site reports that “methane, instead of water,forms Titan’s clouds, rivers, and lakes. Cassini RADAR Team member Dr. Ralph Lorenz has deter-mined that with Titan’s low gravity and dense atmosphere, methane raindrops could grow twice aslarge as Earth’s raindrops, and they would fall moreslowly, drifting down like snowflakes. scientists think itrains perhaps only every few decades, but when it rains onTitan, it really pours.”

In a 2009 space.com article, it was stated that “saturn’smoon Titan may be worlds away from Earth, but the twobodies have some characteristics in common: wind, rain,volcanoes, tectonics, and other Earth-like processes allsculpt features on Titan, but act in an environment morefrigid than Antarctica. ‘It is really surprising how closelyTitan’s surface resembles Earth’s,’ said Rosaly Lopes, aplanetary geologist at NAsA’s JPL in Pasadena, Calif. ‘Infact, Titan looks more like the Earth than any other body inthe solar system, despite the huge differences in tempera-ture and other environmental conditions.’”

In Feb. 2010, NAsA reported, “Cassini’s travel scrap-

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Titan, one of

Saturn’s moons

Saturn

47

book includes more than 210,000 images: information gathered during more than 125 revolutionsaround saturn, 67 flybys of Titan, and eight close flybys of Enceladus. Cassini has revealed unex-pected details in the planet’s signature rings, and observations of Titan have given scientists aglimpse of what Earth might have been like before life evolved.”

UranusUranus is about 1.7 billion miles (19.18 AU) from the sun, about

twice as far as saturn. Uranus is the first planet to be located with thehelp of a telescope, and it was discovered by an astronomer in 1781. Ithas only been since the mid 1980s that we have been able to increaseour knowledge of Uranus. This was due to the Us unmanned Voyager

2 mission which took the spacecraft on a flyby of Uranus in 1986. Uranus is the third largest planet in our solar system, and, like

Jupiter and saturn, it is a gas giant. Uranus has a rocky core sur-rounded by water, ammonia, and methane, in both ice and liquid form.The outer layer consists of hydrogen and helium gases. There is alsomethane in the upper atmosphere, and this gives Uranus a bluish greenish color.

It takes Uranus 84 years to revolve around the sun, and it rotates in about 18 hours. The averagetemperature is about -350° F (-212° C) on Uranus. Its environment is super cold because hardly anysolar radiation reaches Uranus. One unique thing about Uranus is that it spins on its side. scientiststhink that possibly some large body may have bumped into it, resulting in its current position. Be-cause Uranus is tilted 60° on its axis, daylight lasts 42 years followed by 42 years of night. Thismeans that even though the planet is rotating on its axis every 18 hours, it continues to face the sun-light for 42 years because of the 60° tilt.

Like saturn and Jupiter, Uranus has rings around it. It actually has 11 very narrow and blackrings. They are made of dust and chunks of rock. They are very dark and hard to see. Additionally,Uranus has 27 known moons. These moons are made of rocks and ice, and many of the moons, suchas Juliet, are named after characters in literature written by the famous English poet and playwrightWilliam shakespeare. In 2005, the Hubble Space Telescope provided new images and informationabout Uranus’s rings and moons.

NeptuneNeptune is the outermost of the gas planets and is the fourth largest

planet in our solar system. It was discovered in 1846 when scientistsdetermined that something was affecting the orbit of Uranus. Neptuneis about 3 billion miles (30 AU) from the sun, and it takes 165 Earthyears to complete an orbit. so, one year on Neptune equals a littleover 60,000 Earth days, or 165 Earth years. A Neptune day lasts about19 hours. During the day, daylight on Neptune is about 900 times lessbright than on Earth because Neptune is so far away from the sun,making high noon on Neptune seem like a dim twilight.

Neptune and Uranus are so similar they are sometimes called twins. Although a bit smaller thanUranus, both Neptune and Uranus could each hold about 60 Earths inside them. Neptune’s gravita-tional pull and average temperature are also very similar to that of Uranus. Neptune has a rocky coresurrounded by water, ammonia, and methane. The atmosphere consists of hydrogen, helium, andmethane. methane absorbs red light, not blue; therefore, Uranus and Neptune appear to have a blue

Uranus

Neptune

tint, with Neptune’s color being a bit more of a vivid, brighter blue. Regarding methane, pictures ofNeptune show bright clouds of methane ice crystals are present. Like Uranus, we learned a great dealabout Neptune thanks to Voyager 2.

Neptune is a windy planet, the windiest in our solar system. It has recorded winds of 1,500 milesper hour, which is close to the top speed of a F/A-18 Hornet, which is mach 2. storms similar tothose on Jupiter were found during missions. several large dark spots, or storms, were found duringthe Voyager missions. The largest of the storms, the Great Dark spot, was about the size of the Earth.The original Great Dark spot was gone when Hubble took photographs of Neptune in 1995.

Pictures indicate that Neptune has a very thin ring system, which is hard to detect. The ring sys-tem around Neptune is narrow and very faint. The rings are composed of dust particles that scientistsbelieve were made by tiny meteorites smashing into Neptune’s moons.

Neptune has 13 known moons, the largest of which is Triton. Triton is approximately three-fourths the size of Earth’s moon and circles Neptune in 5.875 days. The strange thing about Titan’smovement is that it rotates backwards compared to the other moons of Neptune. Voyager 2 showedactive geyser-like eruptions on Triton spewing invisible nitrogen gas and dark dust particles severalkilometers into space.

Thinking about a manned mission to Uranus? You might change your mind after reading this in-formation from JPL and NAsA: “Trying to land on Neptune is a really bad idea. Like the other threegiant planets, it is a big ball of gas that gradually becomes a hot liquid well below the clouds.There’s nothing on which to land. Anyone foolish enough to drop below the cloud tops would betorn by intense winds, frozen by super cold temperatures, and eventually smashed by the sheerweight of the atmosphere above, which, by the way, is poisonous to humans.”

Pluto A planet or not a planet? Astronomer Clyde

Tombaugh discovered Pluto in February 1930. Plutoremained our official ninth planet until 2006 whenthe International Astronomical Union (IAU) changedthe definition of “planet.” Pluto then no longer metall of the requirements to stay in the same league asthe other eight planets. Pluto was removed from“classical planet” status because it did not meet oneof the new requirements needed to be a planet. Thatrequirement is that the object must dominate its or-bital path. Pluto’s orbit actually crosses Neptune’s, and Pluto orbits in an area of icy rock bodiescalled the Kuiper (pronounced KY-per) Belt. The Kuiper Belt is located beyond Neptune’s orbit andreaches a little past the outermost point of Pluto’s orbit to the edge of our solar system.

Pluto was reclassified as a dwarf planet. A dwarf planet is “a celestial body that (a) is in orbitaround the sun, (b) has sufficient mass to assume a hydrostatic equilibrium (nearly round) shape, (c)has not cleared the neighborhood around its orbit, and (d) is not a satellite.” About two years afterbeing demoted to dwarf planet, the IAU created a special class of dwarf planets known as plutoids,which includes and is named after Pluto. Plutoids are dwarf planets that are located beyond Neptune.All plutoids are dwarf planets, but not all dwarf planets are plutoids. For example, between mars andJupiter, there is a dwarf planet called Ceres. It is not a plutoid because it is not located beyond Nep-tune, as is the case with Pluto.

An interesting characteristic about Pluto is its strange orbit. It is more elongated than any of theother traditional planets, and sometimes is actually closer to the sun than Neptune. For about 20 of

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Poor Pluto

Credit: MathiasPedersen.com

49

248 Earth years (or just a little over 1/12 of a Pluto year), Pluto’sorbit cuts inside Neptune’s, making it closer to the sun than Nep-tune. The last time Pluto’s orbit was inside Neptune’s was from1979-1999. The next time that will happen will be about the year2227.

When classified as a planet, Pluto was the smallest of all of theplanets in our solar system. Pluto’s diameter is about 2/3 that ofEarth’s moon, and Pluto is almost 4 billion miles (39.53 AU) fromthe sun. Pluto rotates once on its axis in about 6.5 Earth days. Ayear on Pluto is about 248 Earth years.

Pluto is a yellowish plutoid that is dark and frozen. The sunwould appear as a bright shining star in the sky, and the average temperature on Pluto is estimated tobe about -350° F (-212° C).

Pluto is believed to have a rocky core with a water and ice layer above the core. The surface ismade up of methane frost.

Hydra, Nix, and Charon are Pluto’s three known moons. (Yes, dwarf planets can have moons.)Charon is half the size of Pluto, making it difficult to tell the two apart. Charon’s rotational period isthe same as Pluto’s, so they travel in synchronous orbit together. However, they spin in opposite di-rections.

so little is known about Pluto and other plutoids, such as Eris, makemake (pronounced mAH-kee-mAH-kee), and others because they are so far away from Earth. much of what we know is be-cause of Earth-based observations and the Hubble Space Telescope. We hope to learn more aboutthese objects and the outer edge of our solar system, and we are counting on the New Horizons or-biter to help us. The New Horizons piano-sized spacecraft was launched in 2006. It will reach Plutoin 2015 and spend time studying Pluto and its moons before traveling further out to study other ob-jects in the Kuiper Belt.

SummaryWe have eight planets and a number of dwarf planets that make up our solar system. Our solar

system includes so many objects: our sun, planets, and moons. It also includes other celestial bodiessuch asteroids, comets, and meteoroids. Our solar system is just a small part of our galaxy which isjust a small piece of the great big universe. (see associated Activity Fourteen and Fifteen at the endof the chapter.)

Pluto

50

Activity Fourteen - How Old Are You?Purpose: Use math skills to determine your age on other planets

Materials: chart provided, pencil, paper, and calculator

Procedures:

1. Calculate your age in Earth days. One year = 365 days.

2. Calculate your age in Earth days for the other planets in the solar system.

3. Then convert the Earth days into Earth years. Example: 14 years old on Earth = 365 x 14 = 5110

Earth days.

Summary: No two planets in our solar sys-

tem take the same amount of time to make

one revolution around the sun; therefore, a

person’s age on Earth would not be the same

if he/she lived on another planet. For exam-

ple, a person who was 12 Earth years old

(4,380 Earth days) would be almost 50 years

old on mercury and just a little over 1 year

old on Jupiter.

Earth one year = 365 days

Mercury one year = 88 Earth days

Venus one year = 243 Earth days

Mars one year = 687 Earth days

Jupiter one year = 11.5 Earth years

Saturn one year = 29.5 Earth years

Uranus one year = 84 Earth years

Neptune one year = 165 Earth years

44

51

Activity Fifteen - Creating a Clay Model of the Solar System

Purpose: Use math skills and clay to create a visual scale model of the solar system.

Materials: 8 index cards, marker, 3 pounds of clay (or dough)

Procedures: Using a marker, label the 8 index cards with the

names of the 8 planets. Then using 3 pounds of modeling clay,

follow the 7 steps listed below.

step 1. Divide the clay into 10 equal parts (tenths).

• Use 6 tenths to make Jupiter.

• Use 3 tenths to make saturn.

• Use the remaining clay (1 tenth) in step 2.

step 2. Divide the remaining clay into tenths.

• Add 5 tenths to saturn.

• Use 2 tenths to make Neptune.

• Use 2 tenths to make Uranus.

• Use the remaining clay (1 tenth) in step 3.

step 3. Divide the remaining clay into fourths.

• Add 3 fourths to saturn.

• Use the remaining clay (1 fourth) in step 4.

step 4. Divide the remaining clay into tenths.

• Use 2 tenths to make Earth.

• Use 2 tenths to make Venus.

• Add 4 tenths to Uranus.

• Combine the remaining clay (2 tenths) and use in step 5.

step 5. Divide the remaining clay into tenths.

• Use 1 tenth to make mars.

• Add 4 tenths to Neptune.

• Add 4 tenths to Uranus.

• Use the remaining clay (1 tenth) in step 6.

step 6. Divide the remaining clay into tenths.

• Use 7 tenths to make mercury.

• Add 2 tenths to Uranus.

• Use the remaining clay (1 tenth) in step 7.

step 7. Divide the remaining clay into tenths.

• Add 9 tenths to Uranus.

Summary: No two planets are exactly the same size. This

activity makes it easy to compare and contrast the size of the

planets in our solar system to one another.

Check your work!

When you finish making

your 8 planets, you

should double-check

your work!

Use a metric ruler to

measure the diameter

of your clay planets in

millimeters (mm).

The diameter of your

planets should be close

to the “scale diameter”

measurements in the

chart.

52

6Aerospace Dimensions

SPACECRAFT

6Aerospace Dimensions

SPACECRAFT

MODULE

Civil Air PatrolMaxwell Air Force Base, Alabama

6

Aerospace Dimensions

SPACECRAFT

6

Aerospace Dimensions

SPACECRAFT

WRITTEN BY

DR. JEFF MONTGOMERY

DR. BEN MIllspauGh

DEsIGN

BaRB pRIBulICK

IllusTRaTIONs

pEGGY GREENlEE

EDITING

BOB BROOKs

susaN MallETT

phOTOGRaphY aND phOTOGRaphIC IMaGEs

BOEING, Nasa

NaTIONal aCaDEMIC sTaNDaRD alIGNMENT

JuDY sTONE

puBlIshED BY

NaTIONal hEaDQuaRTERs

CIVIl aIR paTROl

aEROspaCE EDuCaTION DEpuTY DIRECTORaTE

MaXWEll aFB, alaBaMa 36112

ThIRD EDITION

JuNE 2013

INTRODUCTION

ii

The Aerospace Dimensions module, Spacecraft, is the sixth of six modules, which combined,make up Phases I and II of Civil Air Patrol’s Aerospace Education Program for cadets. Each moduleis meant to stand entirely on its own, so that each can be taught in any order. This enables new cadetscoming into the program to study the same module, at the same time, with the other cadets. Thisbuilds a cohesiveness and cooperation among the cadets and encourages active group participation.This module is also appropriate for middle school students and can be used by teachers to supple-ment sTEm-related subjects.

Inquiry-based activities were included to enhance the text and provide concept applicability. Theactivities were designed as group activities, but can be done individually, if desired. The activitiesfor this module are located at the end of each chapter.

CONTENTS

iii

Introduction .............................................................................................ii

Contents...................................................................................................iii

National Academic Standard Alignment ..............................................iv

Chapter 1. Unmanned Spacecraft ..........................................................1

Chapter 2. Manned Spacecraft .............................................................16

Chapter 3. Living and Working in Space ............................................31

International Space Station

iv

National Academic Standard Alignment

Learning Outcomes- Define satellite.

- Describe an orbit.

- Define apogee and perigee.

- Identify sputnik.

- Define a space probe.

- Describe the related parts that make up a satellite system.

- Describe the global positioning system.

- Describe the X-37’s potential uses.

Important Terms

apogee - the highest point of an orbitCOMSAT - communications satelliteGNSS - Global Navigation satellite systems, the term used for navigational satellitesGOES - Geostationary Operational Environmental satelliteGPS - Global Positioning system, a navigational system used by all areas of societyITSO - International Telecommunications satellite Organization, the world’s largest commercial

satellite communications provider; now called INTELsATLANDSAT - satellite that locates natural resources and monitors conditions on the Earth’s surfaceNAVSTAR GPS - as of 2010, the only fully-operational GNssorbit - the path a satellite takes around a celestial bodyperigee - the lowest point of an orbitsatellite - natural or artificial object in space that orbits the Earthspace probe - satellites that either fly by, orbit, or land on a celestial body, other than EarthSputnik - the first artificial satellite (from Russia)

SATELLITESOrigin

The word satellite comes from the French language meaning a guardor attendant. In 1611, while studying the planets and stars, the Germanastronomer, Johannes Kepler, discovered several objects moving aroundJupiter. He named them satellites of Jupiter — the guardians of the giantplanet.

In today’s world, most of us realize the impact satellites have on ourlives. We know that they affect our televisions and our telephones, andeven help us in predicting the weather. They are a part of our daily lives.Today, astronomers still use the term satellite for natural objects in space. An example of a naturalobject in space is the moon. In fact, the moon is the Earth’s only natural satellite.

1

11

Johannes Kepler

In 1957, the Russianslaunched Sputnik, the firstartificial (manmade) satel-lite. since then, as-tronomers have used theterm satellite for either anatural or an artificial ob-ject in space. We com-monly call any object thatorbits the Earth a satellite.

Artificial Satellites

As mentioned earlier, the Earth has only onenatural satellite, but as you can tell from this chart,there are thousands of artificial satellites. since1957, about 40 countries have launched more than24,000 artificial satellites. Today, there are onlyabout 3,000 usable satellites orbiting the Earth.There are approximately 5,000-6,000 other man-made objects still orbiting Earth, but they are un-usable and considered space junk. Becausesatellites normally only stay in orbit for 5-20years, the rest of the 24,000 have fallen out oforbit and incinerated during reentry into Earth’satmosphere.

In the early days of artificial satellites, thesatellites were unmanned. These unmanned satel-lites are sometimes referred to as unmannedspacecraft. These satellites or spacecraft havemany different missions and are placed in cate-gories based on those missions. some of those cat-egories are communications, navigation, Earthobserving, and weather.

In 1958, the first communication satellite(COMSAT), Score, taped messages from orbit toEarth. It operated for only 13 days, but our nationwas excited. In 1962, Telstar 1 became the firstcommercial satellite. It retransmitted as many as60 two-way telephone conversations at one time.Today, the COmsAT business is huge and grow-ing. National and international corporations are fi-nancing the construction, launch, and operation ofseveral types of COmsATs, including direct tele-vision and video conferencing.

The International Telecommunications

Satellite Organization (ITsO) is the world’s largest commercial satellite communications provider.Now called INTELsAT, it manages a constellation of communications satellites to provide interna-tional broadcast services. In 1989, they launched a satellite that accommodated 15,000 two-way

Telstar I

TDRSS (COMSAT)

2

25,00010,000

Number of Artificial Satellites

1,000100

101

before 1957 1957 1970 1995 2010

voice circuits and two television channelssimultaneously. Now, the ITsO (INTEL-sAT) consists of 53 satellites and providesservices to more than 200 countries.

Another COmsAT is the Tracking andData Relay satellite system (TDRss). TheTDRss consists of nine active satellitesand provides a simultaneous full-time cov-erage for the space shuttle and otherNAsA low-Earth-orbiting spacecraft. Thissystem relays data and communicationsbetween the satellites and Earth.

NAsA established a Deep space Net-work (DsN) which consists of an interna-tional network of antennas that supportsinterplanetary spacecraft missions and as-tronomy observations for exploration ofthe universe. There are three deep spacecommunication facilities placed approxi-mately 120 degrees apart. This allowsthem to provide continuous comrnunica-

tions for planetary spacecraft.Communication satellites provide reliable and timely

communications information around the world. The commu-nications payload consists of the electronics and controls thatensure all signals are received, amplified, and retransmittederror-free to the appropriate destination. successful commu-nication links require a direct line of sight with both thetransmitting and receiving stations on Earth or other satel-lites. Communication today normally involves an intermedi-ate ground station rather than a direct satellite link.

By the late 1960s, navigational satellites came into exis-tence. The first navigational satellite, Transit, was developed toprovide Polaris missile submarines with the ability to fix accu-

Mariner 10 Mars ObserverSyncom IV Communications Satellite

3

Image of a GPS Satellite on orbit about the Earth

Transit Navigational Satellite

rate positions. Global Navigation Satellite Systems (GNSS) is the term now usedfor navigational satellites. GNss allows receivers to determine location (latitude,longitude, and altitude) to within a few meters and provides precise time, as wellas position. As of the summer of 2010, the United states NAVSTAR Global

Positioning System (GPS) was the only fully-operational GNss.Another category of satellites is the natural resources satellites. They locate

natural resources and monitor other conditions on the Earth’s surface. This is thetask of the LANDSAT series of satellites. some of the missions of Landsats are:measure and record radiant energy, monitor agricultural conditions, aid urbanplanners in future development, and manage coastal resources.

Another area where satellites have had a dramatic impact on our lives is inweather. Weather satellites have significantly upgraded the capability and accuracyof weather information. This, in turn, gives us timely information which wecan use for making daily decisions. The pictures we see on televisionweather reports come from Geostationary Operational Environmental

4

LANDSAT 4 image of the Gulf Coast

of southern Louisiana and MississippiLANDSAT: a Earth Observing Satellite

NAVSTAR Global Positioning System

GOES 8 weather satellite

atop an Atlas I rocket being

prepared for launch in 1994

Satellites (GOES). GOEs gives us pictures of the Earth’ssurface, pictures of clouds, and information which helpswith weather forecasting.

NAsA sent the first weather satellite, Tiros I, intospace on April 1, 1960. It sent back an image of a hurri-cane that same day. Weather satellites have come a longway since then. The weather satellites of today havetremendously added to the accuracy of our weather fore-casters. They provide the technology and information thathave particularly helped with forecasting severe weather.Accurately predicting severe weather saves property andlives.

Over the years, satellites have been used for obtainingscientific information in an effort to gain a better under-standing of space. Here are a few of the most importantsatellites and their missions. Explorer was the first andoldest Us satellite series. Explorer 1 was launched in

1958. It discovered the Van Allen Radiation Belts. Later that year, Explorer 3 provided more infor-mation about radiation in space and investigated the presence of micro meteoroids. In 1959, Ex-

plorer 6 gave us our first photograph of Earth from space.One group of satellites, the Orbiting solar Observatory (OsO), provided continuous solar obser-

vations for most of the 1960s and 1970s. The OsO series also furthered our studies of x-rays,gamma rays, and ultraviolet rays.

satellites or spacecraft that either fly by, orbit, or land on a celestial body, other than Earth, arecalled space probes. We’ve had several probes that we should briefly mention. The Rangers were thefirst probes to take pictures of the moon in preparation for the Apollo landings. The Mariner seriesflew by Venus and mercury and gave us pictures of the clouds of Venus and mercury’s cratered sur-face.

In the 1970s, the Pioneer probesgave us pictures of Jupiter and saturn.

5

Early hurricane imagery from Tiros I

Mariner IIPioneer leaving our solar system

In 1975, the Viking seriesexplored the environmentof mars. The Vikings ana-lyzed and photographedthe surface of mars withthe primary emphasis onthe search for life. In thelate 1970s, Voyager 1 and2 also encountered Jupiterand saturn. The Voyagers

provided greatly im-proved pictures and dataof these two planets.

Satellites as a System

satellites as a systemrefers to a satellite’s re-lated parts in a set or asystem. These systems aremade up of people, thespace environment which is orbited, subsystems that support the spacecraft in space, an Earth-boundand a space command and control system, and, finally, a means to get the spacecraft to orbit — alaunch.

There are many people involved in the design, manufacture, launch, and operation of any satel-lite. Plus, this system also includes the customers. As users of the information, they define the over-

6

The System of Satellite Constellations

Environment

PeopleCommand and Control

Launch

Spacecraft

Pictures of Saturn and Jupiter provided by Voyager

Satellite Sub Systems

The Satellite Constellation System

7

all purpose and requirements for thesatellites.

The space environment is somethingwe can’t control. It is extremely danger-ous for both humans and satellites. Forsatellites, atmosphere is a concern be-cause low Earth orbiting satellites mustbattle atmospheric drag, and of coursegravity, which will continue to pull thesatellites toward Earth. Radiation,charged particles, and solar flares arealso potentially dangerous for satellites.Radiation is heat energy emitted fromthe sun that is both good and bad. Theheat gives energy to the solar-poweredsatellites, but can bring harm to thesatellite’s protective coatings over time.The same is true with charged particles and solarflares. Over time these phenomena can harm thesatellite’s protective shields and damage electri-cal equipment.

micrometeorites and space debris can alsoharm satellites. some 20,000 tons of natural ma-terials make it into the Earth’s atmosphere everyyear. most of it burns up, but some does hit theEarth. manmade debris or junk is also a threat. Itis estimated there are over a billion tiny pieces ofjunk, such as slivers of metal and paint chips inspace. Why do we care? We care because in 1983a paint chip of .008 inches hit the spaceshuttle Challenger and caused a cratertwenty times its size (.16 inches) in anorbiter window. Traveling at over 1500miles per hour at impact, a paint chip hastremendous energy. Efforts are underwayto minimize the amount of debris eachmission leaves behind.

The subsystems refer to the supportthat is given to the spacecraft in space.These include the structure, the propul-sion system, attitude control, the powersystem, thermal control, and a commandand control system.

The first aspect that ties the subsys-tems together is the satellite’s mission.The mission defines the satellite’s pur-pose, what services will be provided,why the satellite is being built, and how

Space Environment

Asteroids

Image of a propulsion system being

used for acceleration in deep space

8

TDRSS Satellite tucked neatly into

the Cargo Bay of the Space Shuttle

The Satellite unfolds until its antennas and solar panels

stretch to dimensions larger than the size if a house.

A folded TDRSS Satellite

it should be designed. The first step of the design is to determine the payload requirements. The pay-load refers to the sensors and instruments used to perform the mission, which also determine theother requirements of the satellite.

The structure of a satellite is like a building. It has a frame and windows, and it is insulated tohelp control the temperature. It must be sturdy enough to survive the launch, yet light enough to getinto orbit. It supplies the support for the other subsystems.

The propulsion system provides the boost to get the satellite into orbit. It takes an enormousamount of power to get into the correct orbit and stay there.

To make minor corrections in direction, the attitude control system is used. It steers and controlswhere the satellite is pointed.

Obviously, the power is another important subsystem, and electrical power is the essential ingre-dient. The main source of electricity while the satellite is in orbit is the sun. The solar power is col-lected from the satellite’s solar cells and converted to energy to power the satellite.

A satellite experiences extreme temperature differences while in orbit. There are times when theEarth moves between a satellite and the sun. When this happens, the temperature drops dramatically.many measures can be used to control the temperature, but the most common are insulation andheaters. Both of these help keep the temperature within safe limits. This temperature data is all partof the thermal control subsystem.

The command and control function of a satellite is a communication system. The command por-

9

tion is the signal from the ground station to the satellite. The commands sent to the satellite are com-puter programs. The satellite collects the information and sends it back to the ground station. This iscalled telemetry and this is the information that tells a controller how the satellite is functioning.

The last part of the system is the launch, which gets the satellite into orbit. The mission require-ments determine the orbit needed to accomplish the mission. To meet these requirements, a satellitemust be launched from a particular launch site at a particular time. There is a launch window inwhich this can occur, but it is usually a short period of time. There may be only one or two launchwindows per day.

Orbits and Trajectories

An orbit is the movement or path a satellite takes around a ce-lestial body. We commonly call any object that orbits the Earth asatellite. studying the orbital motion of satellites helpsus understand the capabilities and limitations of thesesatellites.

Greek astronomer Ptolemy (A.D. 127-145) gave usthe first theory of motion of celestial bodies. His the-ory, the geocentric theory, placed the Earth at the cen-ter of the universe. He was wrong, but it was the firstorganized concept of the motion of celestial bodies.Celestial bodies are planets, stars, comets, and anyother large objects in space.

In the 1400s, Copernicus developed a heliocentrictheory of the universe. This theory placed the sun atthe center, and all the rest of the universe revolvedaround it. Copernicus was not entirely correct, becausethe universe does not revolve around the sun as do theplanets and other objects inside our solar system.

These ancient astronomers determined that the mo-tion of celestial bodies was not random. Kepler (infor-mation and photo on page 1) studied the motion and

Satellites orbit the Earth

Copernicus

Telemetry

measured the movement of planets.In the 1600s, he created rules ofmotion which we call Kepler’slaws. All celestial bodies, includingartificial satellites, obey Kepler’slaws. Kepler’s First Law states: Theorbit of each planet is an ellipse,with the sun at the focus.

In an elliptical orbit, the satel-lite’s altitude, velocity, and speedare not constant. Therefore, theshape varies. The shape can rangefrom being very elliptical to almostcircular. During an orbit, the orbit-ing object reaches a high point anda low point. Its highest point iscalled the apogee, and its lowestpoint is called its perigee. Theapogee represents the point where

the object is the farthest away from the body being orbited. The perigee represents the point wherethe object is the closest.

several years after Kepler, sir Isaac Newton developed his laws of motion. Newton’s Laws ofmotion are very helpful to understanding the movement of satellites. These laws are discussed in de-tail in module Four, Rockets. However, Newton’s First Law of motion, called the law of inertia,helps to explain how a satellite stays in orbit and how it leaves an orbit. The first law states that anobject at rest remains at rest and an object in motion remains in motion unless acted on by an unbal-anced force. Another of Newton’s laws, the Law of Universal Gravitation, explains the gravitationalattraction or pull between bodies in the universe. The Earth’s gravitational force is always toward thecenter of the planet. The Earth’s gravity is the dominant force affecting the motion of a satellite in anEarth orbit.

10

Gravity

Apogee Perigee

Elliptical orbit

Gravity pulling the bullet toward the center of the Earth

The Earth’s gravitational force pulling

toward the center of the planet

Varying Ellitical orbital shapes

Elliptical orbits

Gravity gives the orbit its shape. An example of a bullet fired from a gun helps to explain this. Asthe bullet is traveling in a straight line, gravity pulls the bullet toward the center of the Earth. Thecombination of the bullet’s speed and gravity creates a curved flight path. (see associated ActivitiesOne and Two at the end of the chapter.)

The Spacecraft as a VehicleTo get a better understanding of spacecraft and spaceflight, one must first have a basic knowledge

of the environment in which this craft will operate. From an altitude of approximately 62 milesabove the surface of the Earth,space is extremely hostile. Thepressure is near zero and thetemperature in deep space canapproach -400°F.

If a spacecraft is going to op-erate in that environment, with-out a “pilot” or “crew,” it will,for all purposes, be a robot. Ifthe vehicle is unmanned, then itmust be controlled from a com-mand center on Earth. Thespacecraft can be scientific,technological, or a weapon ofwar.

To initiate a spacecraft mis-sion, it must first be launchedfrom one of many sites aroundthe world. If the flight plan isdesignated as “suborbital,” thespacecraft will be programmedto re-enter the atmosphere and return for a land-ing on the Earth’s surface.

If a mission is scheduled to go beyond theEarth’s gravity, it can remain in orbit around theEarth (like the GPs satellites). It can also ex-plore the solar system and beyond if space agen-cies, like NAsA and the European spaceAgency (EsA), have the funding. Unmanned ex-ploration can extend into galactic space.

One example of deep space exploration re-cently was the flight to mercury which occurredin January of 2008. NAsA’s MESSEngER

spacecraft gave scientists an entirely new look ata distant planet once thought to have characteris-tics similar to those found on our moon. After ajourney of more than 2 billion miles and threeand a half years, MESSEngER went into orbit

11

The Hubble Space Telescope: a space vehicle that needs many

subsystems working together to keep it operating for years

MESSENGER spacecraft

around mercury, and provided scientists with a better understanding of our solar system.There is a phrase that states “form follows function.” This means that a form, living or inanimate,

will have a certain shape if it is tofunction well in a given environ-ment. A classic example is theshark. It is designed for high speed,high maneuverability, and very lowhydrodynamic (water) drag. Com-pare the shark to a fighter plane,such as the F-16. The aircraft isvery sleek, has large control sur-faces for maneuverability, and haslow aerodynamic drag. space, onthe other hand, has only minuteamounts of water or air moleculesand the dynamic drag is very low.That is the reason most spacecraftare very unusual in shape. They canbe disks, blocks, rectangular, cylin-drical, etc. An example is the He-lios spacecraft. It is capable of flying at thousands of miles per hour, yet it is not designed toencounter any form of drag.

The Unmanned Spacecraft That Functions Like A Manned VehicleNAsA’s X-37 is an advanced technology flight demonstrator, which may help define the future of

space transportation. The X-37 will test and validate technologies in the environment of space, as

12

The F-16: designed to pass through the air with a very low aerodynamic drag

The Gray Nurse Shark as an

example of “form following function”

Image of the Helios spacecraft: designed to operate in an

environment with extremely low temperature,

extremely low pressure, and no aerodynamic drag

well as test system performance of the vehicle during orbital flight, reentry, and landing. The X-37will aid in the design and development of NAsA’s Orbital space Plane. This aerospace craft is de-signed for several missions, but one of the most significant is to provide a crew rescue and transportcapability to and from the International space station.

The X-37 will operate at the speed of mach 25 and test technologies in the hostile space environ-ment without posing a threat to a human flight crew. Among the technologies to be demonstratedwith the X-37 are improved thermal protection systems, avionics, the autonomous guidance system,and an advanced airframe.

As part of the X-37 project,the Boeing company’s Phan-tom Works division in Hunt-ington Beach, CA, isdeveloping two vehicles: theX-37 approach and landing testvehicle and the X-37 orbitaltest vehicle. These autonomousspace planes, which will haveno crew, will play a key role inNAsA’s effort to dramaticallyreduce the cost of sending hu-mans and life-support systemsinto space.

The X-37 is becomingAmerican’s military spaceplane that can beused for space-based surveillanceand reconnais-sance. The on-board engine is theRocketdyne AR-2/3, which is fueledby hydrogen perox-ide and the jet fuel,JP-8.

The X-37 wasoriginally designedto be carried intoorbit in the spaceshuttle cargo bay,but underwent re-design for launchon a Delta IV orcomparable rocketafter it was deter-mined that a shuttle

13

The X-37 Space Plane

The X-37’s unmanned, remote-controlled landing back on Earth

flight would be uneco-nomical.

The original vehi-cle, which was used inearlier atmosphericdrop glider tests, hadno propulsion system.Instead of an opera-tional vehicle’s pay-load bay doors it hadan enclosed and rein-forced upper fuselagestructure to allow it tobe mated with a moth-ership. most of thethermal protection tileswere made of inexpen-sive foam rather thanceramic; a small num-ber of the X-37’s tileswere actual ThermalProtection shield(TPs) tiles. TPs blan-kets were used in areas where heating would not have been severe enough to require tiles.

On April 7, 2006, the X-37 made its first free-glide flight. During landing, an anomaly caused thevehicle to run off the runway and it sustained minor damage. Following an extended down timewhile the vehicle was repaired, the program moved from the mojave Desert, CA, to Air Force Plant42 (KPmD) in Palmdale, California for the remainder of the flight test program.

On November 17, 2006, the Us Air Force announced it would develop the X-37B from the origi-nal NAsA X-37 A. The Air Force version is designated X-37B Orbital Test Vehicle (OTV). The X-37B was continued in development by the Air Force Rapid Capabilities Office and includespartnerships with NAsA and the Air Force Research Laboratory. Boeing is the prime contractor forthe OTV program. The first orbital flight of the X-OTV-1 occurred on April 22, 2010 on an Atlas Vrocket from SLC-41 at Cape Canaveral Air Force station in Florida. This mission marked the begin-ning of military operations in space.

From Sputnik 1, which was launched on October 4, 1957, to the present, the exploration of un-manned space flight continues. Whether it be for pure science or military superiority, the limit hasbeen raised to include the final frontier of space. Aerospace education is no longer just a study ofman and his/her exploration of the unknown, but also of vehicles that can go to other planets and re-turn data that can eventually bring us closer to how the universe came about. It is hard to imaginewhat life will be like 1,000,000 years from now, but almost daily what was science fiction is now be-coming science fact.

14

Cutaway image of the X-37

15

Activity One - Escape VelocityPurpose: This activity will demonstrate what it takes to achieveescape velocity, such as to leave the gravitational pull of the Earth toenter another area of space.

Materials: cardboard trough (shaped like an m ), two supports ofequal size (books or blocks), piece of glass (windowpane), steel ballbearing, and two strong bar magnets

Procedure: Be sure to study the diagram before you begin the activity toplace the items in the correct positions.1. Tilt the trough slightly upward and release the ball bearing toward the first magnet. What happens?

Does the steel ball have enough escape velocity to pull free of the first magnet?2. To increase the speed of the steel ball, increase the upward tilt of the trough even more and release

the ball near the upper end. What happens as the steel ball coasts through space, and approaches thesecond magnet?

Summary: Escape velocity is commonly described as the speed needed to “break free” from a gravi-tational field. The more speed that is applied to the space vehicle (steel ball) in this activity, thegreater the chance of escaping the gravitational pull of Earth (the first bar magnet) as you coastthrough space (glass pane) and approach the moon (the second bar magnet) with its own gravity field.High velocity is needed for a satellite to go into orbit in space.

Activity Two - Why Do Satellites Stay in Orbit?Purpose: This activity will demonstrate why satellites stay in orbit around the Earth.

Materials: a large thread spool, string, five metal washers, a nylon stocking, and a small rubber ball

Procedure:1. Cut a piece of nylon to put around the rubber ball.2. Tie one end of a string around the nylon.3. Put the other end of the string through the spool and attach the washers to it. 4. Hold the spool in one hand; the washers in the other.5. Begin to whirl the ball over your head.6. Gradually let go of the washers.As you increase the speed of the ball, the washers move

closer to the spool. As you slow down, the washers begin to fall away from the spool. 7. While the ball is whirling, have someone cut the string between the washers and the

spool. The ball will fly away from the spool in a straight line due to its inertia. The ball isheld in orbit around the spool by the string. This corresponds to the force of gravity on asatellite, which causes an inward pull.

Summary: The forward motion of the ball is its momentum. If the gravity of the string were not act-ing on the ball, the ball would continue in one direction. The swinging of the ball gives it its forwardmotion. When these two forces are equal, the ball remains in orbit, without falling into or flyingaway from the Earth (you). When the gravity (washers) is removed, the forces become unbalancedand the ball will fly off in a straight line. A satellite’s forward motion is controlled by rockets. Whenthe rockets are not fired, inertia keeps the satellite going in one direction. When the rockets are fired,the velocity is increased and the satellite can be propellled out of orbit.

11

16

Learning Outcomes- Identify various manned space flight projects and their missions.

- Identify the American and Russian joint manned spacecraft mission.

- Describe the accomplishments of Alan shepard and Neil Armstrong.

- state specific facts about the Hubble space Telescope.

- Discuss the overall mission of the International space station.

- Identify various space shuttle launches and their missions.

- Describe China’s effort in space.

Important Terms

Apollo - Us manned spaceflight project that put man on the moonApollo-Soyuz - manned spaceflight project linking American and soviet spacecraft in spaceGemini - Us manned spaceflight project that achieved the first walk in space, and the first two-man

capsuleMercury - Us first manned spaceflight projectSkylab - Us manned spaceflight project that put a laboratory into spaceSpace Shuttle - Us space Transportation system (sTs) for transporting into space and returning to Earth

FIRST IN SPACEThe soviet Union’s space flight programs

developed along the same lines as the American

programs and occurred approximately the same

times. However, the soviets had several firsts in

the space race.

In 1957, the soviets launched the first satel-

lite, Sputnik, into space. After that, the soviets

launched nine more Sputniks in about 3 1/2

years. The last two were accomplished in prepa-

ration for their first manned space flight.

The soviets also put the first man in space in

April 1961. major Yuri Gagarin was the first

man to escape the Earth’s atmosphere. Although

he only stayed up for one orbit, he described

sights no human eyes had ever seen before.

Then in June 1963, the soviets put the first

22

Yuri Gagarin, the first human in space

17

woman, Valentina Tereshkova, into space. she com-

pleted 48 orbits and was in space for three days before

returning safely to Earth.

In march 1965, Russian Cosmonaut, Alexei

Leonov, became the first person to “walk in space.” He

spent 20 minutes outside of his spacecraft. This oc-

curred about two months before the Americans

“walked in space.”

The soviets launched their first space station, Salyut

1, in April 1971. The soviets sent seven salyuts into

space to complete their space station missions. Salyut 7

fell back to Earth in 1991.

The soviets next space station model was Mir, the

Russian term for peace. Mir was launched in February

1986. Mir did not carry as many specific instruments,

so there was more room and comfort for the cosmo-

nauts (the Russian term for American astronauts). In

1998, the United states sent several space shuttles to

dock with Mir. American astronauts spent over two

years aboard Mir on different occasions.

Mir was scheduled to fall to Earth in 1999. However, the soviets boosted Mir so that it would stay in

space longer. In 2001, as Mir’s rocket boosters propelled it out of orbit, it burned up entering the Earth’s at-

mosphere. Its remains ended up in the Pacific Ocean. This ended a 15-year 2.2 billion mile journey and the

historic era of the Russian space station program.

PROJECT MERCURY The United states launched its first satellite in 1958, and by 1961 the Us was ready to attempt

manned spaceflight. America’s first manned spaceflight program was called Project Mercury. mer-

cury’s mission was to find out if a human could survive space travel, and

what, if any, effects would space travel have on the human body.

Project mercury lasted two years and consisted of six manned flights. The

first flight involved

sending one astronaut

into space. This first

flight was suborbital

and lasted for only 15

minutes, but on may

5, 1961, astronaut

Alan shepard became

the first American in

space. Project mer-

cury’s third manned

flight was also its first

orbital flight. DuringCutaway image of the Mercury capsule

Alan Shepard in

Mercury flight suit.

The Soviet Space Station, Mir

this flight, astronaut John Glenn became the first American to orbit the Earth.

He remained in orbit for four hours and fifty-five minutes, while orbiting the

Earth three times.

On the final mercury

flight, astronaut Gordon

Cooper orbited the Earth

22 times and stayed in

space for about 34 hours

and 20 minutes. Project

mercury answered the

basic questions about sur-

vival in space. Project

mercury accomplished its

mission.

PROJECT GEMINIThe next manned spaceflight project was Project Gemini. There were a

total of 10 Gemini flights between 1965 and 1966. Gemini was the first

two-man capsule, and during one of the missions, astronaut Ed White

achieved the first Us “space walk.” Additionally, Gemini allowed for the

first rendezvous and docking of a manned spacecraft with another satellite.

The Gemini flights gathered additional information about the effect of

spaceflight on the human body. The astronauts studied the effects of weightlessness and were in-

volved in an exercise program. At times, they removed their space suits and relaxed in shirtsleeves.

Because the flights lasted for several days, the astronauts were able to establish routines for sleeping

and eating. Enough information was gathered to convince scientists that a space flight could safely

last for several weeks or even months. These Gemini flights were very valuable in America’s plan to

place a man on the moon.

18

Gemini IV’s astronaut Ed White

during a 22-minute space walk

John Glenn entering his capsule, Friendship 7

The two-man Gemini capsule

Freedom 7, ready to

carry Shepard into space

19

PROJECT APOLLOAfter the Gemini missions

were completed, Project Apollo

took center stage in America’sspace program. From the early1960s, it was known that Apollo’smission would be to put a man onthe moon. so, the Apollo flightswere conducted with that overallgoal in mind. several of the earlyApollo flights traveled to themoon, orbited it, and returned toEarth. It was not until Apollo 11that the mission was accom-plished. Apollo 11 landed on themoon, and on July 20, 1969, NeilArmstrong was the first man towalk on the moon.

A few minutes later, Edwin“Buzz” Aldrin also stepped off the ladder ofthe Lunar module and joined Armstrong onthe moon. many have called that landing thegreatest scientific and engineering accom-plishment in history. After Apollo 11, therewere six more Apollo flights to the moon.Five of them resulted in successful moonlandings.

The only flight of the six that didn’t landon the moon was Apollo 13. Apollo 13 had tobe aborted due to an explosion in the space-craft. However, Apollo 13 did make a suc-cessful emergency landing back on Earth.

Aldrin joins Armstrong on the Moon

Neil Armstrong, the first human to walk on the Moon

The Apollo 11 astronauts, Edwin E. "Buzz"

Aldrin, Michael Collins, and Neil A. Armstrong

PROJECT SKYLABProject Skylab, the next spaceflight

project, used a lot of leftover equipmentfrom the Apollo missions. Skylab’s mis-sion was to put a laboratory into space.scientists had been interested in continu-ing their studies of the effects of long-du-ration space flights using a mannedorbiting laboratory. This was accom-plished when Skylab was launched inmay 1973.

Skylab had about the same amount ofroom as a three-bedroom house. It alsocontained all of the food, water, and oxy-gen needed to support the entire mission.

Three different crews spent time in thelab. The first crew manned Skylab for 28days. The second crew spent 58 daysaboard the laboratory. The final crewspent 84 days in space. The main lesson that came from Skylab was that people could live and work inspace for at least three months with no ill effects.

PROJECT APOLLO-SOYUZAfter the Apollo flights, the last manned

space launch before the space shuttle was theApollo-Soyuz Test Project. This occurred inJuly 1975 and involved a linkup in space ofAmerican and soviet manned spacecraft. Thiswas a unique moment in history. These two su-perpowers that had been involved in a well-pub-licized space race for 15 years, met and shookhands in space. This was indeed a special mo-ment.

The two crews docked together and spent twodays moving between the capsules helping eachother with scientific experiments. Among theAmerican crew were former mercury and Gemini astronauts. Among the soviet crew wasAlexei Leonov, the first man to “walk in space.”This joint venture truly was an historic event.

Apollo-Soyuz marked the end of an era. Itmarked the end of the expendable spacecraft. Anew era was being ushered in, the era of thereusable space vehicle, the space shuttle.

20

Skylab

Image of the Apollo-Soyuz project

21

SPACE SHUTTLEThe United states space Transportation system (sTs), commonly known as the space shuttle Pro-

gram, has served the country well for 30 years. However, as this module is being prepared, plans are todiscontinue the program in 2012. Proposed new space programs are in the planning stages to replace theaging system. more about those new programs will be discussed later in this chapter but, first let’s dis-cuss the space shuttle Program and its accomplishments over the years.

From 1975 until 1981, the Us didn’t have any astronauts in space, but that changed with the spaceshuttle. In April 1981, the Space Shuttle was launched. The space shuttle provided a system for trans-portation into space and a return back to Earth. This has been a major advantage of the shuttle since itcan be used again and again.

The space shuttle consists of three main parts: the orbiter, the solid rocket boosters, and the externaltank. The orbiter looks like an airplane and is about the same size as a DC-9 jet. The orbiter carries thecrew and the payload. The other two parts are required to launch the shuttle into space. The boostersburn away and the tank separates early into the flight.

When the shuttle was first built it could remain in space for 14 days. That time has increased to 30days now. When it is time for the shuttle to return to Earth, the astronauts fire the two orbital maneuver-ing engines, which slow down the shuttle. The shuttle then reenters the Earth’s atmosphere.

The first space shuttle was actually the Enterprise, but it was only used for flight tests. It was not de-signed for going into space. The other five space shuttle spacecraft have all gone into space and havebeen used for a variety of missions. They are the Columbia, Challenger, Discovery, Atlantis, and En-

deavour.

The first four flights of the Columbia were mainly tests. most of the concern centered around how theColumbia would handle reentry into theEarth’s atmosphere and how its protectiveshields would perform. sTs-5 was the firstreal operational flight, and it occurred in No-vember 1982. From orbit, the sTs-5launched two satellites.

Over the years, the space shuttle has beenused in many ways to further our knowledgeof space. The first American woman in space,Dr. sally Ride, was aboard the Challenger forsTs-7. sTs-9 delivered the first European

The Rollout of the Space Shuttle Challenger

before it’s first launch in 1983

Dr. Sally Ride, first American woman in space,

with the crew of the Challenger mission STS-7

space Agency spacelab into space.sTs-13 placed the Long Duration Ex-posure Facility (LDEF) into space toconduct experiments. A few yearslater, the LDEF was retrieved and themany experiments analyzed.

On January 28, 1986, less than twominutes after takeoff, the Challenger

(sTs-51L) exploded. The entire crewof seven died. A leak in one of thesolid rocket boosters was the cause.After the Challenger accident, theshuttle program was suspended forover two years. After design changeswere made, and safety procedures andprecautions taken, on september 29,1988 the space shuttle flights re-sumed.

In April 1990, the shuttle Discov-

ery deployed the Hubble Space Tele-

scope. The Hubble Telescope isoperating at over 300 miles above theEarth and is free of any atmosphericinterference. Therefore, the objects

are seen much more clearly than fromground observations. The telescope is ex-pected to operate until at least 2014 due toservicing provided by three separate spaceshuttle missions.

Atlantis, with mission sTs-34, placedthe galileo probe into space. The galileo

probe investigated Jupiter and its moonsuntil 2003. In 1993, sTs-55 carried the Eu-ropean developed Spacelab into orbit. manyuseful experiments were conducted fromthe Spacelab.

In July 1994, Payload specialist Chiakimukai became the first Japanese woman tofly in space. she was part of sTs-65 thatperformed more than 80 experiments thatdelved into life sciences, space biology,human physiology, and radiation biology. InFebruary 1995, Pilot Eileen Collins becamethe first female shuttle pilot. Later in 1995,the 100th Us human space launch occurredwhen sTs-71 was launched. sTs-71 alsomarked the first Us space shuttle andRussian space station Mir docking.

22

Two astronauts repairing and servicing

the Hubble Space Telescope

Atlantis launching Galileo probe into space

23

In 1996, five space agencies (NAsA/Us; European space Agency/Europe; French spaceAgency/France; Canadian space Agency/Canada; and Italian space Agency/Italy) and research scientistsfrom 10 countries worked together on the primary payload for sTs-78. more than 40 experiments wereconducted on microgravity science, human physiology, and space biology. sTs-78 was the first to con-duct comprehensive sleep studies and task performance in microgravity.

In 1998, the ninth and final space shuttle-Mir docking took place, and then later in 1998, John Glennreturned to space. John Glenn had been the first American to orbit the Earth in 1962, and after a success-ful career in the Us senate, he became the oldest human to venture into space when he was part of thecrew aboard sTs-95. John Glenn was 77 years old when he returned to space. In December 1998, thefirst International space station (Iss) flight occurred with sTs-88. This was the first of several missionsto construct the Iss. (You can read more about the Iss in later chapters of this module.)

sTs-93 was launched in 1999 and commanded by Commander Eileen Collins. This was the firstspace shuttle in history to be commanded by a woman. she was the first woman pilot and eventuallythe first woman commander in space.

In 2001, as part of sTs-102, astronauts susan Helms and Jim Voss conducted the longest spacewalkin shuttle history. The spacewalk lasted 8 hours and 56 minutes. Then in 2002, mission specialist JerryRoss, aboard sTs-110, became the first human to fly in space seven times.

On February, 1, 2003, sTs-107 Columbia and her seven-member crew were lost during re-entry overTexas. Damage was sustained during launch and this created a hole allowing hot gases to melt the wingstructure. The resulting investigation and modifications interrupted shuttle flight operations for morethan two years.

In may 2009, the sTs-118 crew included Barbara morgan, and she became the first teacher to visitspace. morgan had been the backup teacher when the 1986 Challenger disaster occurred. Also in 2009,sTs-125 conducted the final servicing mission for the Hubble space Telescope. Hubble’s lifespan wasextended until at least 2014.

As mentioned at the beginning of this section, the sTs program is coming to an end. A special spaceshuttle mission scheduled for sTs-133 will be piloted by Eric Boe, a former CAP spaatz cadet and cur-rent CAP senior member.This will be Eric Boe’ssecond mission aboard aspace shuttle. This willmark the 36th shuttle mis-sion to the Iss, the 133rdshuttle flight, and the finalflight of the Discovery or-biter.

The space shuttle hasbeen the workhorse ofAmerica’s space programsince 1981. The shuttlehas carried many astro-nauts to successful mis-sions and these missionshave greatly increased ourknowledge of space. (seeassociated Activity Threeat the end of the chapter.)

Eileen Collins STS 93 Mission Commander

24

MANNED SPACEFLIGHT – THE HUMAN VENTURE CONTINUESThe Timeline of Manned Space Flight – 1961-2010*

Russia / UssR United states China Total

1961–1970 16 25 41

1971–1980 30 8 38

1981–1990 24 37 61

1991–2000 20 63 83

2001–2010 20 31 3 54

Total missions 110 164 3 277

*As of August 2010

A CURRENT PICTUREAs has been discussed, and as the chart above indicates, Russia and the United states have been

active in spaceflight programs since the 1960s. For many years the two countries have worked sideby side achieving major accomplishments in the exploration of space. many other countries havealso been active in space, particularly with the development of the International space station (Iss).Countries such as, Canada, Japan, and Brazil and many others have contributed to the developmentof the Iss. But there is another country that hasn’t been part of the Iss, but is now very active inpursuing space, and that country is China.

In 2003, China launched its first manned spacecraft, ShenZhou 5, and then followed that with twomore manned spacecraft missions in 2005 and 2008. China is also developing a spacecraft dockingsystem that should be ready in 2010 or 2011. Then, China intends to place an astronaut on the moon.many observers believe that will happen in the next few years. so, China is aggressively catching upto Russia and the United states.

meanwhile, Russia’s current space priorities include developing new communications, naviga-tion, and remote sensing spacecraft. Russia’s current space budget remains unchanged with approxi-mately 50% spent on their manned space program. Russia has indicated that they want to completetheir segment of the Iss and also are considering missions to the moon and mars. Russia is alsoworking on new rocket launchers to support their missions.

The United states space program is at a crossroads. The current Constellation program is underreview and may be cancelled. Its goal of returning to the moon and then on to mars may be in jeop-ardy. The Us is currently considering continu-ing pursuit of mars and/or concentrating oncommercial spaceflights. With the end of thespace shuttle program, immediate political de-cisions will determine the direction and extentof America’s future space involvement. Tripsto the Iss are still a distinct possibility, butAmerican astronauts may be traveling onRussian rockets. On the other hand, the Ares Icrew launch vehicle and the Orion capsulemay still carry American astronauts to the Iss.As of the preparation of this module, these dif-ficult decisions had not been made. (see asso-ciated Activity Four at the end of the chapter.) China Astronaut

25

Activity Three - The Space Shuttle GliderPurpose: This activity creates a model of the space shuttle glider (orbiter) and allows experimentationwith how the shuttle glides in for a landing.

Materials: old file folders (1 makes 2 gliders), glue sticks or hot glue, scissors

Procedure:1. Copy the templates shown on following pages on color copier.2. Glue the templates to heavy paper or file folders.3. Using scissors, neatly cut out all parts.4. Cut 13 V-shaped notches in the fuselage to create tabs along outside edge.5. Fold tabs out.6. Glue or tape three nose weights to underside of your glider. Use fourth nose weight

provided, if needed for extra trim after assembly.7. Fold fuselage along middle line.8. starting at the nose, glue or tape fuselage to deck and wing assembly. match tabs on fuselage exactly

to the ones printed on the deck and wing assembly.9. To close the nose, glue or tape the two halves together using tabs provided.10. Fold vertical stabilizer assembly. 11. Fold out tabs A and B. Except for tabs A and B, glue or tape vertical stabilizer assembly to make one

solid piece.12. Attach, with glue or tape, vertical stabilizer to fuselage, matching tab A with

point A and tab B with point B.

Preflight Instructions:For best results, launch your shuttle glider with agentle, level toss. Bend the Body Flap upslightly for greater lift.

Summary: The space shuttle glider is ascale model of the actual space shuttleorbiter in the space Transportation sys-tem (sTs). As the glider is put to-gether, discussion can revolve aroundsuch terms as fuselage, tail and wing as-sembly, and vertical stabilizer assembly.These terms can be compared to airplaneparts. The fuselage is the main body of theaircraft that holds crew, passengers, and the cargo(called the payload). The actual shuttle’s wing span is 78ft. The shuttle’s vertical tail consists of a structural fin surface,the rudder/speed brake surface, a tip, and a lower trailing edge. The ruddersplits into two halves to serve as a speed brake. Like the fin of an aircraft, the vertical stabilizer keeps theshuttle on course in the Earth’s atmosphere, and helps it to steer.

22G L U ES T IC K

Space Shuttle Glider

Assembly Example

26

Space Shuttle Glider Bottom

27

Cut 13Notches

Line of Fold

Line of Fold

Fold UpTabs

Space Shuttle Glider

Fuselage Assembly

28

Deck and Wing

Assembly

29

Vertical Stabilizer Assembly

Glider kit designed for NAsA byKentron Hawaii, Ltd.Artist: Roland O. Powell

t

a

b

b

t

a

b

a

30

Activity Four - See How the Earth Looks to an Astronaut

Purpose: This activity will help you understand the perspective of an astronaut as he/she views Earth

from space.

Materials: 16" Earth globe and a 4" moon globe

Procedure:

1. Using the summary information below, calculate the distance

between the Earth and the moon using a model where the

Earth is 16 inches in diameter and the moon is 4 inches in di-

ameter. (The Earth is 30 Earth diameters from the moon, or

about 40 feet.)

2. measure the distance from your calculation. Inflate a 16-inch Earth

from space globe.

3. Have one person hold the Earth globe at the beginning point of the distance meas-

urement you made.

4. Have another person hold the moon globe at the ending point of the distance

measurement you made.

5. standing with the person holding the moon globe, you can “look back” at Earth and have an idea of

the view of our planet from space.

Summary: The distance from the Earth to the moon is 240,000 miles on average, because the moon is

in an elliptical orbit around Earth (due to the gravitational pull of the sun). so, sometimes, it is closer to

the Earth than other times. The circumference of the Earth is 25,000 miles. Considering the size of the

Earth, the moon is about 9.5 Earth circumferences away from the moon. In relation to the scaled Earth

and moon in this activity, that means if the circumference of the 16” diameter Earth globe is 50.24”

(C=πd), then the distance from the Earth globe to the moon globe should be 9.5 x 50.24” = 477.28” or

39.77 ft (about 40 ft).

31

Learning Outcomes- Describe Space Station Alpha.

- Explain the differences between Mir and Skylab.

- Define Spacelab.

- Describe the significance of Salyut 1.

- Describe the living and working conditions in space.

- Describe the different space suits.

- Define and give examples of spinoffs from the space program.

- Describe possible future space endeavors.

Important Terms

Mir - Russia’s space station of the 1980s and 1990sSalyut - Russia’s first space stationSkylab - first space station of the UsSpacelab - European space Agency’s first space station

SPACE STATIONSThe idea of a permanent space station has been with us since the beginning of the space race. The

benefit of having a way station en route to the moon or the planets has been recognized for sometime. For scientific, research, and even military reasons, a permanent space station has been consid-ered a necessity.

Russia launched the first space station,Salyut 1, in April 1971. Russian astronautsdocked and stayed on board for three weeks.Salyut 1 stayed in space for six months,then burned up when it reentered theEarth’s atmosphere.

Russia continued to launch severalspace stations in the Salyut series. manyof the missions resulted in Russian as-tronauts staying in space for 1-2months. Salyut 6 and 7 both stayed inspace about four years. The as-tronauts stayed aboard Salyut 7for a record 234 days.

The success of the Salyut

series brought on the nextmodel of Russian space sta-

Soyuz TMSpacecraft Docking

Compartment

Hatch

Portholes

Work andDining Table

Treadmill

Solar panels

ExerciseBicycle

Work Compartment

Toilet and Washing Area

SatelliteAntenna

PropulsionCompartment

Docking Port for Progress Supply Vehicles

Rendezvous Antenna

Control Center

33

The Mir Space Station

32

tion, the Mir. Mir

was launched inFebruary 1986 andwas about the samesize as Salyut. How-ever, Mir didn’tcarry as much scien-tific equipment, so ithad more privacy,comfort, and spacefor the astronauts.

In 1998, Mir was

frequently in the

news. This was due

to several malfunc-

tions that were oc-

curring. The United

states sent the space

shuttle to Mir sev-

eral times to help

with repairs. In fact,

American astronauts

spent over two years

aboard Mir on differ-

ent missions. Mir

was scheduled to fall

back to Earth in

1999. However, The

Russians boosted

Mir to stay in space

longer. so, despite

early problems Mir remained in space until 2001.

The first Us space station was Skylab. As mentioned earlier, it was launched in may 1973 two

years after Salyut. Three different crews lived in the Skylab. The last crew stayed for 84 days, which

was the longest of the crews. During their stays, the crews conducted many experiments. They

demonstrated that people could live and work in space. No other crews visited Skylab, but it re-

mained in space for six years before reentering Earth’s atmosphere and falling back to Earth. most of

Skylab burned up on reentry, but some pieces landed in the Indian Ocean and were recovered.

The European space Agency developed a “short-term” space station called Spacelab, which was

a reusable laboratory used inside the payload bay of a space shuttle. Spacelab was used on over 20

space shuttle missions between 1983 and 1998, providing an environment dedicated to scientific re-

search and hands-on experiments.

Radiator

Shower

Waste Disposal

Food Table

Skylab StudentExperiments

Earth ObservationWindow

French Ultra-violetExperiment

Food Freezer

EnvironmentalControl System

Entry Hatch &Airlock Interface

Locker Stowage

Water Supply

Waste Mgt Odor Filter

Body Weight Device

Fecal UrineSampling

Waste Tank

MicrometeoroidShield

WASTE MGTCOMP

SLEEP COMPARTMENT

Skylab StudentExperimentED-52 Web FormationOperational Mode

WARD ROOM

FORWARD COMPARTMENT

EXPERIMENTCOMPARTMENT

Skylab Orbital Workshop

33

INTERNATIONALSPACE STATION (ISS)

The Iss is an internationallydeveloped research facility beingassembled in low Earth orbit.After several years of planningand preparation, the first missionto assemble the Iss took place inNovember 1998. The Iss isscheduled for completion in2011. It is the largest interna-tional scientific project in historywith sixteen countries contribut-ing to this massive undertaking.The countries involved are:UsA, Russia, Japan, Canada,Brazil, and 11 European coun-tries.

The purpose of the Iss is toachieve long-term exploration ofspace and to provide benefits tothe people of Earth. since No-vember 2000, a continual humanpresence has existed on the Iss.Astronauts began by staying a few days on the Iss and some have now extended that stay to a fewmonths. During this time, hundreds of scientific experiments have been conducted on the Iss.Human research, microgravity, life sciences, physical sciences, and astronomy are a few of the pri-mary fields that have been studied.

The Iss is the largest satellite in space and can be seen from Earth with the naked eye. It orbitsthe Earth at an altitude that varies from 173 miles (278 km) to 286 miles (460 km) at a speed of

The International Space Station on orbit

Spacelab on board the Space Shuttle Columbia

34

17,227 miles per hour. The Iss constantly loses altitude due to atmospheric drag but is boostedseveral times a year to regain its higher altitudes. It completes 15.7 orbits in a 24-hour period.You can track the Iss to determine when you can view it as it flies overhead. Go tohttp://www.spaceflight.nasa.gov/realdata/sightings/ for sighting opportunities.

LIVING AND WORKING ON SPACE STATIONSWhat is it like inside a space station? Well, first of all, microgravity or near weightlessness exists

inside the Iss. We have probably all seen pictures of astronauts floating around inside of space sta-tions. This is not really a problem. Astronauts have learned how to cope with near weightlessness.They can hold on to the walls, or they can wear special cleats, or they can even strap themselves in ifthey want.

The air inside the Iss is a mixture of oxygen and nitrogen. This works better than breathing pureoxygen. Also, the temperature is regulated so that the astronauts are comfortable in t-shirts andshorts or sport shirts and pants.

On the Skylab, the crews had a dining room, a toilet area, and bedrooms.The astronauts could eat either hot or cold food. They would place their feetand legs in restraints and could actually sit and eat. As for sleeping, the astro-nauts had sleeping bags placed vertically on the walls. They could fasten them-selves in and go to sleep.

Living on the International space station (Iss) is similar to the previousspace stations, but also different. First of all, the food has gotten better. Astro-nauts pick their menus months ahead of time knowing how important their dietis in space. The Iss has a microwave and a refrigerator, so even though dehy-drated food is still used, so is frozen food. Drinks and soups are still sippedthrough plastic bags and straws. solid food is eaten with a knife and fork ontrays with magnets to prevent them from floating away.

Working is also a part of life inside a space station. Astronautshave their housekeeping chores to perform. Plus, they have their re-search and experiments to conduct. sometimes they have satellitesto deploy or retrieve, or maybe they have to repair a satellite. Physi-cal activities are a normal daily occurrence on the flights. so, thereis plenty to keep the astronauts busy.

Near weightlessness causes loss of bone and muscle mass, so ex-ercise is very important to astronauts. To prevent this muscle loss,astronauts exercise daily. The Iss is equipped with two treadmillsand a stationary bicycle. Astronauts must strap themselves to theequipment to keep from floating away. The negative effects of nearweightlessness reverse quickly once astronauts return to Earth.

sleeping in the Iss is similar to earlier space stations. Astronautsstill sleep in wall-mounted sleeping bags that zip them into the bag. They also have arm restraints tokeep their arms from floating above their head while they sleep.

Astronauts spend most of their waking moments conducting scientific experiments and observa-tions. They are also involved in maintaining the Iss and repairing equipment, as necessary. Gener-ally, the astronauts work for 10 hours during the weekdays and 5 hours on saturday. The rest of thetime they either relax or do catch-up activites. The Iss doesn’t have a shower, so the astronauts takesponge baths or clean themselves with washcloths and wet towels. Each astronaut has a personal hy-giene kit with toothbrush, toothpaste and shampoo. (see associated Activities Five and six at the endof the chapter.)

Near weightless in space

Foot restraints

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EXTRAVEHICULAR ACTIVITIES (EVA)These last few paragraphs have discussed life inside a space station. Now, let’s spend a little time

discussing life outside the space station. many times a space shuttle mission would include repair-ing a satellite. This involved going outside of the shuttle. The general term used for going outside ofthe shuttle is Extravehicular Activity.

Russian Alexei Leonov accomplished the first EVA or “space walk” in march 1965. He was out-side of his spacecraft for about 20 minutes. Less than three months later, Ed White was the firstAmerican to “walk” in space. This occurred in June 1965. White was outside the spacecraft for 22minutes traveling at 18,000 miles per hour. since 1965, there have been many EVAs in space.

One recent EVA involved the Hubble Space Telescope. Astronauts made repairs to the Hubble

Telescope during an EVA. These successful repairs will allow the telescope to stay in space longer. “spacewalks” have become a very routine part of most of the Iss missions. There have been well

over 250 “spacewalks.” The longest one occurred in 2001 when the “space walk” of astronautssusan Helms and Jim Voss lasted for 8 hours and 56 minutes. They were part of the sTs-102 Dis-

covery crew and despite the numerous “spacewalks” that have occurred since 2001, this record stillstands.

Eating with food strapped

to cabin ceiling

Exercising muscles to keep them

from wasting away in microgravity

Eating with food

strapped to lap

A nice warm shower A shave Sally Ride in a sleep restraint

SPACE SUITSObviously, a subject that

comes to mind when talkingabout space walks is spacesuits. space suits have changeda lot over the years. Let’s take alook at the evolution of thespace suit. space suit designbegan in the 1930s with high-altitude flyers. These suits werereally pressure suits. Over thenext 30 years, the technologyimproved. However, the earlyastronauts of Project mercurystill wore pressure suits.

During the Gemini flights, alightweight, easily-removablespace suit was developed. It wasduring Gemini 7 that space suitswere taken off inside of thespacecraft for the first time.Prior to that, astronauts leftthem on during the entire flight.

Initially, the space suitswere very immobile. It washard for the astronauts to movearound. However, as the spaceflights progressed and morewas expected of the astronauts,

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An EVA near Skylab An Atlantis EVA

Taking a look at the Hubble Space Telescope

Pressure suits worn by the seven

Mercury astronauts

A more advanced suit for moon

walking for the Apollo astronauts

Lightweight space suits

wore by Gemini astronauts

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the space suits got better. Comfort andmobility became higher priorities.

The Apollo moon suit was more ad-vanced than previous suits. The astronautscarried their oxygen on their backs andcould communicate, as well. The suit alsohad a supply of drinking water and a col-lection point for going to the bathroom.

All of these space suits consisted ofseveral layers of material. This protectedthe astronauts during EVAs. For instance,the Apollo suit protected the astronaut intemperatures of over 250° F, while alsoprotecting against harmful radiation.

All of these space suits were madespecifically for the individual astronaut.That changed with the space shuttle. Theshuttle suit was much easier to put on.The astronauts dressed one layer at atime. The shuttle suit was made of sev-eral parts that could accommodate a manor a woman. It was also reusable and expected to last for 15 years.

In 1984, the astronauts used the manned maneuvering Unit (mmU) for the first time. This unit fiton the back of the astronaut’s space suit and allowed him or her to move around without being tied tothe spacecraft. The mmU was used on three missions, all of which occurred in 1984. After the Challenger tragedy in 1986, the use of the mmU was discontinued due to safety concerns. An im-proved version of the mmU, the simplified Aid for EVA Rescue (sAFER), was first flight-tested dur-ing sTs-64 in 1994. It was developed for use in case a tethered astronaut performing as EVA becameuntethered.

As you can see, space suits have come a long way. The improvements in the suits have allowed theastronauts to do much more in space, and do it more efficiently. To see NAsA ideas for future space-suits, “Google” future spacesuits on the internet. You will be amazed at the future technology plannedto protect mankind in space. (see associated Activities seven and Eight at the end of the chapter.)

THE FUTURE IN SPACEDue to our enduring fascination with space, indications are that space travel will continue into the

unforeseeable future. We have come a long way since Russia launched Sputnik in 1957, and witheach additional mission we seem to learn more and more. In many people’s minds, this increasedknowledge justifies a persistent, progressive space program.

For almost the last 30 years, the United states’ space Transportation system (sTs), has been theprimary mode of space transportation. The space shuttle is scheduled to retire in 2011. What will re-place it? As of the preparation of this module the answer is unclear. Indications are that the Interna-tional space station (Iss) will remain in space until at least 2020. so, it’s easy to assume trips willbe made to the Iss. Russia and the United states are seeking more cooperation in space travel, andusing a Russian space shuttle to take American astronauts to the Iss is being considered.

In 1999, the X-37 Orbital Test Vehicle began as a NAsA project and was transferred to the UsDepartment of Defense in 2004. The X-37’s first test flight was in 2006 at Edwards Air Force Base,

The Manned Maneuvering Unit

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California, and then its first orbital flight was inApril 2010 using an Atlas V rocket. Its successfulreturn to earth resulted in two more missions, onein 2011 and another in 2012.

In 2006, the Us Air Force announced it woulddevelop its own version of the X-37. They called itthe X-37B Orbital Test Vehicle (OTV), and it wasdesigned to remain in orbit for up to 270 days at atime. The OTV-1 was launched in 2010 andplaced in low Earth orbit for testing. It circled theEarth every 90 minutes on an orbit of from 249 to262 miles above Earth. In December 2010, theOTV-1 landed at Vandenberg AFB, CA, after 224days in space, becoming America’s first au-tonomous orbital landing onto a runway. OTV-2 and OTV-3 missions have continued with efforts totest new space technologies. The missions have been classified.

NAsA has looked beyond 2020 and has envisioned something like the Spaceliner. This vehiclewould take off like a plane, most likely on a rail system, and be powered by air-breathing rockets andramjets. The spaceliner is being designed to take about 50 passangers to 47-50 miles above Earth andthen glide back to Earth at hypersonic speeds of more than 15,000 mph. This would enable passengersto fly from Europe to Australia in 90 minutes. The spaceliner is aiming to fly passengers by 2050.This is one idea, but the technological challenges are daunting and funding must be available. Regard-less, if space travel continues, it is the goal to make it cheaper, safer, and more reliable.

Another distinct possibility is commercial space travel. Virgin Galactic and scaled Compositesare working together to make commercial space travel a reality. scaled Composites is the companythat in 2004 won the $10 million X-Prize for flying at a altitude of 62 miles or 100 kilometers, re-turning safely to Earth, and then repeating the flight within two weeks. The spacecraft was calledSpaceShipOne. Now, the two companies are building a spacecraft called SpaceShipTwo that will takepassengers into space. Initially, tickets can be purchased for $200,000. The spacecraft is designed toseat six passengers and two pilots and fly to about 68 miles, or 110 kilometers. The passengers willexperience a 2 ½ hour flight with several minutes of near weightlessness. Already, countries areplacing orders for the SpaceShipTwo.After about 50-100 test flights,SpaceShipTwo is expected to takepassengers in 2014.

Regardless of the direction ittakes, the United states will probablystay heavily involved in space formany years. Additionally, Russia hasannounced a renewed interest inspace, and China is coming on strongand wants to increase its involve-ment. China has even expressed in-terest in placing a person on themoon. so, with these and other coun-tries involved, the exploration ofspace should remain an importantissue for the world for many years.

The X-37 in the clouds

Future Transatmospheric Aircraft

Cre

dit: N

AS

A/M

ars

ha

ll

39

SPINOFFS FROM THE SPACE PROGRAM – Putting Space Technology To Work Back On Earth

Our day-to-day lives have been touched by many space technologies. It has been recorded thatsince the mid-seventies, over 1,600 documented NAsA inventions have benefitted our quality of lifeand has provided Americans with a large number of jobs.

many have heard that Tang, Velcro, and microcomputers were all spinoffs of space technology.Actually, this is not the case; however, there have been some achievements that are very common-place in our daily lives. A few examples, put into an easy-to-understand form are:

TV Satellite Dish

NAsA developed ways to correct errors in the signals coming from satel-lites. This technology is used to reduce noise (that is, interference to pictureor sound) in TV signals coming from satellites.

Medical Imaging

NAsA developed ways to process signals from spacecraft to produceclearer images. (see more on digital information and how spacecraft sendimages from space on the internet.) This technology also makes possiblethese photo-like images of the inside of the human body.

Vision Screening System

This uses techniques developed for processing space pictures to examineeyes of children and find out quickly if they have any vision problems. Thechild doesn’t have to say a word!

Ear Thermometer

Instead of measuring temperature using a column of mercury (which ex-pands as it heats up), this thermometer has a lens-like a camera and detectsinfrared energy, which we feel as heat. The warmer something is (like yourbody), the more infrared energy it puts out. This technology was originallydeveloped to detect the birth of stars.

Fire Fighter Equipment

Fire fighters wear suits made of fire-resistant fabric developed for use inspace suits.

Smoke Detector

This was first used in the Earth orbiting space station called Skylab

(launched back in 1973) to help detect any toxic vapors. It is now used inmost homes and other buildings to warn people of fire.

Sun Tiger Glasses

This comes from research done on materials to protect the eyes ofwelders working on spacecraft. Protective lenses were developed that blockalmost all the wavelengths of radiation that might harm the eyes, while let-ting through all the useful wavelengths that let us see.

Automobile Design Tools

This is a computer program developed by NAsA to analyze a space-craft or airplane design and predict how parts will perform. It is nowused to help design automobiles. This kind of software can save carmakers a lot of money by letting them see how well a design will workeven before they build a prototype.

Cordless Tools

Portable, self-contained power tools were originally developed tohelp Apollo astronauts drill for moon samples. This technology has ledto the development of such tools as the cordless vacuum cleaner, powerdrill, shrub trimmers, and grass shears.

Aerodynamic Bicycle Wheel

A special bike wheel uses NAsA research in airfoils (wings) and de-sign software developed for the space program. The three spokes on thewheel act like wings, making the bicycle very efficient for racing. sur-prisingly, this technology has also helped in the design of more aerody-namic bicycle helmets.

Thermal Gloves and Boots

These gloves and boots have heating elements that run on recharge-able batteries worn on the inside wrist of the gloves or embedded in thesole of the ski boot. This technology was adapted from a spacesuit de-signed for the Apollo astronauts.

Space Pens

The Fisher space Pen was developed for use in space. most pens de-pend on gravity to make the ink flow into the ball point. For this spacepen, the ink cartridge contains pressured gas to push the ink toward theball point. That means you can lie in bed and write upside down withthis pen. Also, it uses a special ink that works in very hot and very coldenvironments.

The Most Famous Spinoff

Football helmets use a padding of Temper Foam, a shock absorbingmaterial, that was first developed for use in aircraft seats. It is the mostrecognized and widely-used NAsA spinoff. Temper Foam, whose origindates back to 1966, was developed to absorb shock and offer improvedprotection and comfort in NAsA’s airplane seats. It has paid its divi-dends to Earth repeatedly, and in many different ways. It has padded the

helmets of the Dallas Cowboys throughout the 1970s and 1980s, protected bedridden patients frombedsores, and comforted the feet of thousands wearing stylish shoes that incorporate the cushioningmaterial in their insoles.

Four decades later, the world has come to realize that there are no bounds to Temper Foam’s ben-efits. Though the rights to the technology have been shared amongst various manufacturers, the orig-inal product maker is still going strong, pushing Temper Foam into new arenas, includingautomotives, amusement parks, prosthetics, sleep items, and modern art.

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41

Ski Boots

These ski boots use accordion-like folds, similar to the design of spacesuits, to allow the boot to flex without distortion, yet still give support andcontrol for precision skiing.

Failsafe Flashlight

This flashlight uses NAsA’s concept of system redundancy, which meansalways having a backup for the parts of the spacecraft with the most impor-tant jobs. This flashlight has an extra-bright primary bulb and an independ-ent backup system that has its own separate lithium battery (also a NAsAdeveloped technology) and its own bulb.

Invisible Braces

These teeth-straightening braces use brackets that are made of a nearlyinvisible translucent (almost clear) ceramic material. This material is a spin-off of NAsA’s advanced ceramic research to develop new, tougher materialsfor spacecraft and aircraft.

Edible Toothpaste

This is a special foamless toothpaste developed for the astronauts to usein space (where spitting is not a very good idea).

Joystick Controllers

Joystick controllers are used for lots of things now, including computergames and vehicles for people with disabilities. These devices evolved fromresearch to develop a controller for the Apollo Lunar Rover, and from otherNAsA research into how humans actually operate (called "human factors").

Advanced Plastics

spacecraft and other electronics need very special, low-cost materials asthe base for printed circuits (like those inside your computer). some of these"liquid crystal polymers" have turned out to be very good, low-cost materi-als for making containers for foods and beverages.

spinoff technology has had a large impact within the field of medicine. Thousands of lives havebeen saved with the development of procedures and machines such as:

1. A NAsA-developed chemical process was responsible for the development of kidney dialysismachines.

2. The need to find imperfections in aerospace structures and components, such as castings,rocket motors, and nozzles, led to the development of a medical CAT scanner which searchesthe human body for tumors or other abnormalities. CAT stands for Computer Tomography scan.

3. It is well known that the near weightlessness experienced while living in space can lead tophysical deterioration, cardiovascular problems, and muscle atrophy. A space exercise machineled to the development of a physical therapy and athletic development machine used by foot-ball teams, sports clinics, and medical rehabilitation centers.

4. A hospital food service system employs a cook/chill concept for serving food. The system al-lows staff to prepare food well in advance, maintain heat, visual appeal, and nutritional value,while reducing operating costs.

Because of budget changes and the amount of funding available to space exploration, it is diffi-cult to predict what the future will be in aerospace technology. However, we, as Americans, can saythat our space adventure over the past 50 years has been of great benefit to all mankind.

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33Activity Five - Investigating Near WeightlessnessPurpose: This activity will use the scientific method and in-

quiry to experiment with the concept of near weightlessness.

Materials: ping-pong ball, golf ball, plastic Dixie cup,

round wooden bead or a metal nut, and a piece of string

Procedure:

1. Cut the string into two pieces, one long and one short.

2. Attach the longer piece to the rim of the plastic cup like a

pail handle.

3. Attach the wooden bead or metal nut to one end of the

shorter piece by tying a knot at the end to hold the bead on the string.

4. start with the ping-pong ball and the golf ball. Hold one ball in each hand. From the same height and

at the same time, drop the two balls. Observe the results.

5. set the plastic cup on a table.

6. Hold the string with the bead at the end over the cup. Let go of the string and observe. What happens?

7. Now carefully stand on a chair or stool. Hold the string handle of the cup. Hold the end of the bead

string in the same hand, with the string in the middle of the handle so the bead hangs over the cup.

8. Hold the cup and the ball high and drop them together. What happens this time?

9. Discuss as a group what was expected to happen and what actually happened for each action.

Summary: Galileo (1564-1642) was a scientist who achieved many accomplishments in the fields of as-

tronomy and physics. Galileo was the person who discovered that all objects fall at a constant rate of

speed on Earth, no matter what their size or weight. Due to Galileo’s experiments, today we have an ac-

curate picture of how the near “weightlessness” in space works. Near weightlessness occurs when two

objects (the bead and the cup) are free-falling in gravity. But what keeps the space shuttle from free

falling to the Earth like the cup and the bead? A spacecraft can maintain its free fall for a very long pe-

riod of time by traveling fast enough -- about 7.5 kilometers (4.7 miles) per second — horizontally, so

that even though it is being pulled toward the center of the earth, its free-fall path is parallel to the earth’s

curvature. In other words, the spacecraft continually falls all the way around the earth. This microgravity

or sensation of weightlessness refers to an environment in which the local effects of gravity have virtu-

ally been eliminated by free-fall.

Plastic cup

String Handle

Ping-PongBall

GolfBall

String with wooden bead attached

Activity Six - How Does Motion Cause Disorientation?Purpose: This activity will demonstrate how our senses help orient us in

space and how motion causes disorientation.

Materials: swivel chair, blindfold, pencil, and a friend

Procedure:

1. Ask a friend to sit in a swivel chair and put on a blindfold. The friend

places arms out in front of the body, holding a pencil in an upright posi-

tion.

2. Ask your friend to point the pencil in the direction of rotation as you

turn the chair. slowly stop the chair. Then turn the chair in the opposite direc-

tion. Watch the pencil.

3. stop the chair. Watch the pencil. In what direction did your friend point the pencil after the first rotation?

When the chair was stopped? After the second rotation? Discuss how our senses help orient us in space.

Summary: The results of this activity are that motion causes disorientation and sight is one of our

senses that help us stay oriented. In space, there is a disorientation resulting from the conflict between

the signals coming from the vestibular system (consisting of the semicircular canals and the special or-

gans of the inner ear), which no longer correspond with the visual and other sensory information sent to

the brain and the new spatial reality. The normal concepts of "up" and "down" no longer apply. This

same disorientation is demonstrated in the activity because of the blindfold and the

spinning of the chair.

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Activity Seven - Keeping Cool

Purpose: This activity will demonstrate how a spacesuit liquid cooling

system works to moderate body heat.

Materials: 2 empty coffee cans with plastic snap-on lids, 2 ther-

mometers (must be able to read a full range of temperatures from

freezing to boiling), black spray paint, floodlight and light fixture,

plastic aquarium tubing (6 meters), masking tape, 2 buckets, ice,

water, stopwatch or watch with a second hand, graph paper, and

metal punch or drill

Procedure:

1. spray paint the outside of both cans black and permit them to dry.

2. Punch a hole in the center of each lid and insert a thermometer.

3. Punch a second hole in one of the lids large enough to admit the aquarium tubing. Also punch a hole in

the side of that can near its base.

4. Form a spiral coil with the plastic tubing along the inside wall of the can with the hole punched in its

side. Be sure that the coil doesn’t touch the thermometer directly. Do not pinch the tube. Extend the

tube’s ends out of the can, one through the hole in the can and the other through the hole in the lid. The

upper end of tube should reach into the elevated water bucket and the other should hang down from

the side of the can toward the lower bucket.

5. set up the floodlight so that it will shine on the sides of the two cans. make sure the light is equidis-

tant from the two cans.

6. Fill one bucket with ice and water. make sure there is enough ice to chill the water thoroughly.

7. Elevate the ice water bucket on a box or some books next to the can with the tubing.

8. Insert the long end of the aquarium tubing into the bottom of the ice water bucket. Using your mouth,

suck air from the other end of the tube to start a siphoning action. Permit the water to drain through

the tubing that runs through the black can into a second bucket on the floor.

9. Immediately turn on the floodlight so that both cans are equally heated.

10. Begin recording temperatures, starting with an initial reading of each thermometer just before the

light is turned on and every 30 seconds thereafter until the water runs out.

11. Plot the temperature data on graph paper, using a solid line for the can that held the ice water and a

dashed line for the other can. Construct the graph so that the temperature data are along the Y (verti-

cal) axis and the time data along the X (horizontal) axis.

12. Compare the slope of the plots for the two cans.

Summary: In spacesuit design, one of the challenges is to maintain a comfortable temperature inside the

suit when the temperatures in space are so extreme. This activity demonstrates how chilled water can

keep a metal can from heating up even when exposed to the strong light of a floodlight. An astronaut’s

body heat, released from exertion during extravehicular activities, can quickly build up inside a space

suit, leading to heat exhaustion. Body heat is controlled by a liquid cooling garment made from stretch-

able spandex fabric and laced with small diameter plastic tubes that carry chilled water. The water is cir-

culated around the body. Excess body heat is absorbed into the water and carried away to the suit’s

backpack, where it runs along a porous metal plate that permits some of it to escape into outer space.

The water instantly freezes on the outside of the plate and seals the pores. more water circulates along

the back of the plate. Heat in the water is conducted through the metal to melt the ice directly into water

vapor. During the process, the circulating water is chilled.

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Activity Eight - Bending Under PressurePurpose: This activity simulates the mobility of a spacesuit arm.

Materials: 2 long balloons, 3 plastic bracelets or thick

rubber bands

Procedure:

1. Inflate one balloon fully and tie it.

2. Inflate the second balloon, but while it is inflating, slide the bracelets

or bands over the balloon so that the balloon looks like sausage links.

3. Compare the "bendability" of the two balloons.

Summary: maintaining proper pressure inside a spacesuit is essential

for survival. However, pressure produces problems. An inflated spacesuit is hard to bend. Designers

have learned to strategically place breaking points at appropriate places to make the suit bend more. In

this activity, the rings serve as the breaking points. These rings create joints. Further spacesuit research

has shown that built-in ribs, like a clothes dryer or vacuum cleaner hose, promote easier bending.