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Mars Cart

Brief Summary

Over the past three decades, more than 40 spacecraft have been launched towards

Mars, from flybys and orbiters to rovers and landers that touched surface of the Red

Planet. These spacecraft have shown us that Mars is rocky, cold, and dry beneath its

hazy, pink sky. From what we've discovered to date, Mars has given us hints at a

formerly volatile world where volcanoes once raged, meteors plowed deep craters, and

flash floods rushed over the land.

Today, Mars continues to throw out new questions with each landing or orbital pass

made by our spacecraft. At this time in the planet's history, Mars' surface cannot

support life, as we know it. A key science goal is determining Mars' past and future

potential for life.

Among the most sophisticated and exciting rover missions to date are NASA’s Mars

Pathfinder/Sojourner in 1997, the twin Mars Exploration Rovers (MER) Spirit and

Opportunity in 2004, and the Mars Science Laboratory (MSL) Curiosity in 2012. To

date, only Opportunity and Curiosity are continuing of their missions on the surface of

Mars. There are also orbiting missions including NASA’s Mars Reconnaissance Orbiter

(MRO), Mars Atmosphere and Volatile EvolutioN (MAVEN) and ESA’s Mars Express,

that continue to play integral roles in our understanding of the Red Planet.

Equipment Required

Mars Cart

Mars Exploration Rover Model

Laptop or iPad

HDMI Adapter for Laptop

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Mars Cart Mars Exploration Rover Model located by Gates Planetarium

Included on the Mars Cart:

Natural Color Mars Globe

Topographic Mars Globe

Gale Crater Model with MSL (Curiosity) landing site

3-D Printed Model of Gale Crater

MER Rock Abrasion Tool (RAT) abrasion surface model

Aerogel sample

Life on Mars in a Box

Several NASA Resource Binders

Set Up

Retrieve cart and laptop computer or iPad from 2003 storage room. Make sure you have a supply of the Space Odyssey website reference cards to give to our guests.

If using laptop, download the sets of photos on PowerPoint for (1) Mars Exploration Rover (MER) and (2) Mars Science Lab on the Space Odyssey portal:

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Retrieve the Mac to HDMI adapter from the storage area behind the MER Model if want to plug laptop into screens by Mars Exploration Rover model. Next to this adapter is a switcher box. Push button in the center to switch screens to laptop input.

Set-up cart and laptop to the right to the Mars Exploration Rover Exhibit (on the side of the West Atrium).

Use the AMX Panel by the Mars Exploration Rover exhibit to turn on lights

Mars Exploration Rovers

Main Teaching Points

Point out the major components and operation of the MER, using the full-size model.

Use MER mission video on the screens to show visitors how the MERs reached Mars and began operating

Using the Rock Abrasion Tool abrasion surface model, demonstrate how the MER’s RAT works.

New knowledge from the rovers and orbiting spacecraft contributes to meeting the four overarching goals of the Mars Exploration Program:

1. Determine if life ever arose on Mars,

2. Characterize the climate of Mars

3. Characterize the geology of Mars

4. Prepare for human exploration

Provide highlights of some of the discoveries that have been made by the Mars Exploration Rovers

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Background Information

Adapted from: http://mars.nasa.gov/mer/mission/spacecraft.html

The Rover Body

The rover body is called the warm electronics box, or "WEB" for short. Like a car body,

the rover body is a strong, outer layer that protects the rover´s computer, electronics,

and batteries (which are basically the equivalent of the rover´s brains and heart). The

rover body thus keeps the rover´s vital organs protected and temperature-controlled.

Like the human body, the Mars Exploration Rover cannot function well under

excessively hot or cold temperatures. In order to survive during the temperature swings

from day to night, the rover´s "vital organs" must not exceed extreme temperatures of -

40º Celsius to +40º Celsius (-40º Fahrenheit to 104º Fahrenheit).

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The rover´s essentials, such as the batteries, electronics, and computer, which are

basically the rover´s heart and brains, stay safe inside a Warm Electronics Box (WEB),

commonly called the "rover body."

There are several methods engineers used to keep the rover at the right temperature:

Preventing heat escape through gold paint

Preventing heat escape through insulation called "aerogel"

Keeping the rover warm through heaters

Making sure the rover is not too hot or cold through thermostats and heat

switches

Making sure the rover doesn't get too hot through the heat rejection system

Many of these methods are very important to making sure the rover doesn´t "freeze to

death" in the cold of deep space or on Mars. Many people often assume that Mars is

hot, but it is farther away from the sun and has a much thinner atmosphere than Earth,

so any heat it does get during the day dissipates at night. In fact, the ground

temperatures at the rover landing sites swing up during the day and down again during

the night, varying by up to 113 degrees Celsius (or 235 degrees Fahrenheit) per Mars

day. That´s quite a temperature swing, when you consider that Earth temperatures

typically vary by tens of degrees on average between night and day.

The rover is also kept warm by a special layer of insulation, called solid silica aerogel,

which prevents heat from escaping outside of the rover body walls. Aerogel traps heat

inside the rover body. It is a unique silicon-based substance nicknamed "solid smoke"

because it is 99.8% air. Aerogel is one thousand times less dense than glass, so it is

extraordinarily lightweight, which makes it much cheaper and easier to launch and fly to

Mars.

Aerogel is a powerful material. Not only can it block heat from leaving the Mars

Exploration Rover body, but it´s the same material used to trap "cosmic bullets" for the

Stardust spacecraft that flew through a comet's tail in January of 2004, just as the

rovers were reaching Mars.

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A sample of aerogel. Image courtesy NASA Aerogel samples on Mars Cart.

Science Instruments

On board the Mars Exploration Rovers are several science instruments. They include:

Panoramic Camera (Pancam)

Microscopic Imager (MI)

Engineering cameras: Hazcams and Navcams

Miniature Thermal Emission Spectrometer (Mini-TES)

Mössbauer Spectrometer (MB)

Alpha Particle X-Ray Spectrometer (APXS)

Rock Abrasion Tool (RAT)

Magnet Array

The instruments use calibration targets, including a sundial, to determine accurate

colors, brightnesses, and other information collected by the instruments.

The Panoramic Camera (Pancam)

Pancam is a high-resolution color stereo pair of CCD cameras used to image the

surface and sky of Mars. The cameras are located on a "camera bar" that sits on top of

the mast of the rover.

The Pancam Mast Assembly (PMA) allows the cameras to rotate a full 360° to obtain a

panoramic view of the Martian landscape. The camera bar itself can swing up or down

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through 180° of elevation. Scientists use Pancam to scan the horizon of Mars for

landforms that may indicate a past history of water. They also use the instrument to

create a map of the area where the rover lands, as well as search for interesting rocks

and soils to study.

The Pancam cameras are small enough to fit in the palm of your hand (270 grams or

about 9 ounces), but can generate panoramic image mosaics as large as 4,000 pixels

high and 24,000 pixels around.

Each "eye" of the Pancam carries a filter wheel that gives Pancam its multispectral

imaging capabilities. Images taken at various wavelengths can help scientists learn

more about the minerals found in Martian rocks and soils. Blue and infrared solar filters

allow the camera to image the sun. These data, along with images of the sky at a

variety of wavelengths, help to determine the orientation of the rover and provide

information about the dust in the atmosphere of Mars. The Pancam color imaging

system has, by far, the best capability of any camera ever sent to the surface of another

planet.

The Microscopic Imager

The Microscopic Imager is a combination of a microscope and a CCD camera that

provides information on the small-scale features of Martian rocks and soils. It

complements the findings of other science instruments by producing close-up views of

surface materials. Some of those materials are in their natural state, while others may

be views of fresh surfaces exposed by the Rock Abrasion Tool.

Microscopic imaging is used to analyze the size and shape of grains in sedimentary

rocks, which is important for identifying whether water may have existed in the planet's

past. The Microscopic Imager is located on the arm of the rover. Its field of view is 1024

x 1024 pixels in size and it has a single, broad-band filter so imaging is in black and

white.

Miniature Thermal Emission Spectrometer (Mini-TES)

Mini-TES is an infrared spectrometer that can determine the mineralogy of rocks and

soils from a distance by detecting their patterns of thermal radiation. All warm objects

emit heat, but different objects emit heat differently. This variation in thermal radiation

can help scientists identify the minerals on Mars. Mini-TES records the spectra of

various rocks and soils. These spectra are studied to determine the type of minerals

and their abundances at selected locations. One particular goal is to search for minerals

that were formed by the action of water, such as carbonates and clays. Mini-TES also

looks at the atmosphere of Mars and gathers data on temperature, water vapor, and the

abundance of dust.

Mini-TES weighs 2.1 kg (almost 5 lbs) and is located in the body of the rover at the

bottom of the "rover neck," known as the Pancam Mast Assembly (PMA).

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Mössbauer Spectrometer (MB)

Many of the minerals that formed rocks on Mars contain iron, and the soil is iron-rich.

The Mössbauer Spectrometer is an instrument that was specially designed to study

iron-bearing minerals. Because this science instrument is so specialized, it can

determine the composition and abundance of these minerals to a high level of accuracy.

This ability can also help us understand the magnetic properties of surface materials. It

is one of four instruments mounted on the turret at the end of the rover arm.

Measurements are taken by placing the instrument's sensor head directly against a rock

or soil sample. One Mössbauer measurement takes about 12 hours.

Alpha Particle X-Ray Spectrometer (APXS)

The APXS determines the elemental chemistry of rocks and soils using alpha particles

and X-rays. Alpha particles are emitted during radioactive decay and X-rays are a type

of electromagnetic radiation, like light and microwaves. The APXS carries a small alpha

particle source. The alphas are emitted and bounce back from a science target into a

detector in the APXS, along with some X-rays that are excited from the target in the

process. The energy distribution of the alphas and X-rays measured by the detectors is

analyzed to determine elemental composition. Knowing the elemental composition of

Martian rocks provides scientists with information about the formation of the planet's

crust, as well as any weathering that has taken place.

As with the other instruments on the arm of the rover, the APXS sensor head is small

enough to hold in your hand. Most APXS measurements are taken at night and require

at least 10 hours of accumulation time, although just X-ray alone will only require a few

hours.

Rock Abrasion Tool (RAT)

Rock Abrasion Tool (RAT). Image

courtesy NASA RAT Rock Sample on the Mars Cart

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The Rock Abrasion Tool is a powerful grinder, able to create a hole 45 millimeters

(about 2 inches) in diameter and 5 millimeters (0.2 inches) deep into a rock on the

Martian surface.

The RAT is located on the arm of the rover and weighs less than 720 grams (about 1.6

lbs.). It uses three electric motors to drive rotating grinding teeth into the surface of a

rock. Two grinding wheels rotate at high speeds. These wheels also rotate around each

other at a much slower speed so that the two grinding wheels sweep the entire cutting

area. The RAT is able to grind through hard volcanic rock in about two hours.

Once a fresh surface is exposed, scientists can examine the abraded area in detail

using the rover's other science instruments. This means that the interior of a rock may

be very different from its exterior. That difference is important to scientists as it may

reveal how the rock was formed and the environmental conditions in which it was

altered. A rock sitting on the surface of Mars may become covered with dust and will

weather, or change in chemical composition from contact with the atmosphere.

The RAT on Spirit wore out by the time the rover’s mission ended after more than 7

years on the planet’s surface.

Magnet Arrays

Mars is a dusty place and some of that dust is highly magnetic. Magnetic minerals

carried in dust grains may be freeze-dried remnants of the planet´s watery past. A

periodic examination of these particles and their patterns of accumulation on magnets of

varying strength can reveal clues about their mineralogy and the planet´s geologic

history.

The rover has three sets of magnetic targets that will collect airborne dust for analysis

by the science instruments. One set of magnets is carried by the Rock Abrasion Tool

(RAT). As the RAT grinds into Martian rocks, scientists have the opportunity to study the

properties of dust from these outer rock surfaces.

A second set of two magnets is mounted on the front of the rover at an angle so that

non-magnetic particles will tend to fall off. These magnets are reachable for analysis by

the Mössbauer and APXS instruments. A third magnet is mounted on the top of the

rover deck in view of the Pancam. This magnet is strong enough to deflect the paths of

wind-carried, magnetic dust.

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Engineering Cameras

Four Engineering Hazcams (Hazard Avoidance Cameras):

Mounted on the lower portion of the front and rear of the rover, these black-and-white

cameras use visible light to capture three-dimensional (3-D) imagery. This imagery

safeguards against the rover getting lost or inadvertently crashing into unexpected

obstacles, and works in tandem with software that allows the rover make its own safety

choices and to "think on its own."

The cameras each have a wide field of view of about 120 degrees. The rover uses pairs

of Hazcam images to map out the shape of the terrain as far as 3 meters (10 feet) in

front of it, in a "wedge" shape that is over 4 meters wide at the farthest distance.

Two Engineering Navcams (Navigation Cameras):

Mounted on the mast (the rover "neck and head), these black-and-white cameras use

visible light to gather panoramic, three-dimensional (3D) imagery. The Navcam is a

stereo pair of cameras, each with a 45-degree field of view to support ground navigation

planning by scientists and engineers. They work in cooperation with the Hazcams by

providing a complementary view of the terrain.

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Entry and Descent:

Below is a step-by-step guide of the entry and descent portion of the video that plays by the Mars Exploration Rover model. This is plan for entry and descent created by NASA prior to the arrival of Spirit and Opportunity on Mars in 2004.

Initial Preparations

Step One: Communications Prep Begins

Around 6:45 pm PST, the mission team will be preparing the spacecraft for communications during entry, descent, and landing. Spirit's cruise stage switches from its medium-gain antenna (which requires pointing toward Earth), to its low-gain antenna, which does not need to be pointed as precisely for the Deep Space Network antennas to pick up the signal. This switch slows the rate of data transmission, but is

necessary to allow communications to continue when the spacecraft changes its orientation to point its heat shield forward.

Step Two: Spacecraft Rotates

A few minutes after 7 pm PST, the spacecraft carrying Spirit will rotate to face its heat shield forward for its final approach.

Step Three: Transmission of Tones Begins

About a quarter after 8 pm PST, Spirit will begin transmitting tones back to Earth that indicate the spacecraft's status. A low-gain antenna on the spacecraft's backshell begins transmitting simple "tones" (sustained radio frequencies coded to report the spacecraft's status). These tones give Spirit a way to keep communicating after the cruise stage is jettisoned. A dictionary of about 100 possible tones can provide

information such as whether the cruise stage has separated, whether the parachute opens, and whether the deceleration rate is within the expected range.

Step Four: Cruise Stage Separates

As the tones begin, the cruise stage separation commences. This separation is the first stage the rover takes in shedding more than half of the spacecraft in which it has been warmly travelling during its 302.6 million mile journey through the frigid temperatures of space.

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"Six Minutes of Terror"

About 8:29 pm PST, one of the most challenging aspects of the mission begins. In only six minutes, the spacecraft will slow down from 12,000 to 0 miles per hour.

Step Five: Spirit enters the Martian atmosphere

The lander should come streaking in through the Martian atmosphere, going about 12,000 miles per hour. Given atmospheric friction, the outside surface of the heat shield will be as hot as the surface of the sun (1,447 degrees Celsius, or 2,637 degrees Fahrenheit), but the rover will be protected by the heat shield and will stay at about room temperature inside the lander. The heat shield also aerodynamically acts as the first

"brake" for the spacecraft, slowing Spirit down by thousands of miles per hour.

Step Six: Parachute Deploys

About four minutes later, the spacecraft slows to about 1,000 miles per hour and is only 30,000 feet above the Martian surface. At this point, a supersonic parachute is deployed. The parachute is based on the designs and experience of those used in the Viking and Pathfinder missions. The parachute for this mission is about 40% larger than Pathfinder's, and is made of two durable lightweight fabrics (polyester

and nylon).

Step Seven: Heat Shield Jettisons

Twenty seconds after the chute deploys, the heat shield's work is complete, and it separates from the lander.

Step Eight: Lander Separates

Ten seconds after the heat shield jettisons, the lander separates from the back shell and descends to the end of a "bridle", or tether. Spirit's altitude is about 20,000 feet at this point. The lander "rappels" down a Zylon tape on a centrifugal braking system built into one of the lander petals. The slow descent down the Zylon tape places the lander in position at the end of another bridle, which is made of a nearly 20-

meter-long (65-foot-long) braided Zylon, an advanced fiber material similar to Kevlar. The Zylon bridle provides space for airbag deployment, distance from the solid rocket motor exhaust stream, and increased stability. The bridle incorporates an electrical harness that allows the firing of the solid rockets from the backshell, as well as provides

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data from the backshell inertial measurement unit (which measures rate and tilt of the spacecraft) to the flight computer in the rover.

Step Nine: Radar Ground Acquisition Begins

Around 8:34 pm PST, when the lander is about 8,000 feet above the surface, radar systems on the lander determine its altitude and vertical velocity relative to the martian surface. These measurements will help the landing system decide how long to fire the retro rockets to bring the lander's verticle speed close to zero.

Step Ten: Descent imager takes pictures of the surface

While radar measurements are acquired, a descent imager will take three pictures of the surface and compare high-contrast features (for example, a crater) to determine the horizontal velocity at which the lander is moving across the surface. This measurement helps determine which transverse rockets should be fired in the retro rocket system.

Step Eleven: Data transmission to the Mars Global Surveyor orbiter begins

The descent UHF (ultra-high frequency) antenna, mounted on the lander, begins transmitting once the lander descends from the backshell, which stays attached to the parachute. From the lander's position at the bottom of a tether (aka bridle) connected to the backshell, this antenna can transmit to the Mars Global Surveyor orbiter that will be passing overhead at this time. The link allows Spirit to supplement the

tone-coded information with additional status reports that can be forwarded to Earth by Mars Global Surveyor almost immediately. The window for relaying information to Mars Global Surveyor closes by about 8:42 p.m., when the orbiter sets below the landing site's horizon, about seven minutes after Spirit hits the ground. Although this communication link has been extensively planned and simulated, there is no guarantee that Mars Global Surveyor will successfully relay information from Spirit. When the lander descends from the backshell, a low-gain X-band antenna mounted on the rover itself takes over from the backshell antenna the job of transmitting tones to Earth. It transmits tones until retro rockets fire, six seconds before impact. Then, during the spacecraft's impact, bouncing, and rolling, it transmits a carrier signal only.

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Step Twelve: Airbags inflate

Airbags inflate to protect the lander for a soft lading over the hard rocks on Mars. The airbags used in the Mars Exploration Rover mission are the same type that Mars Pathfinder used in 1997. Airbags must be strong enough to cushion the spacecraft if it lands on rocks or rough terrain and allow it to bounce across Mars' surface at freeway speeds after landing.

Step Thirteen: Retro rockets fire

At this point in entry, descent, and landing, the lander is only a football-field length off the ground. Three rockets fire, bringing the airbag-cocooned lander to zero vertical velocity nearly 40 feet off the ground.

Step Fourteen: Bridle is cut and first impact occurs

At about the height of a four-story building and three seconds before landing, the bridle is cut and the vehicle freefalls to the surface. The mass of Spirit and its lander is about 544 kilograms (1,200 pounds).

Final Landing Stage

Step Fifteen: Lander rolls to complete stop

The rover, protected by its lander structure and airbags, could bounce up to four or five stories high and roll as far as 1 kilometer (0.6 miles) across the martian surface before it comes to a complete stop around 8:45 pm PST.

Step Sixteen: Communication attempt begins

About 14 minutes after Spirit hits the ground and four minutes after it stops bouncing and rolling, transmission of tones resumes from the rover's low-gain X-band antenna. If the rover lands with its base petal down, this antenna will be near the top of the bundle and in a position that may be favorable to sending a signal to Earth. Its transmission of tones ends 150 seconds later. The lander, however, may not be in this

orientation. Therefore, beginning about three minutes later, another low-gain X-band

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antenna, this one mounted on the lander's base petal, transmits tones for 150 seconds as well.

Step Seventeen: Critical deployments begin

Immediately after landing, the rover will go through a series of critical deployments for 80 minutes or longer, depending on which base petal it lands. The lander will retract its airbags, deploy its lander petals and solar arrays, and raise its

panoramic camera mast.

Step Eighteen: Data transmission to the Mars Odyssey orbiter begins

The Mars Odyssey orbiter passes across the sky above the landing site for about 15 minutes. If Spirit gets through its critical deployments in time, it will use the rover's UHF antenna to send information, perhaps including images, to Odyssey. Odyssey forwards that information to Earth between 11 p.m. and midnight PST. However, Spirit might not be ready to communicate with Odyssey by the time the orbiter flies

overhead, especially if Spirit ends its roll with a side petal instead of its base petal down. Also, as with the communications attempt with Mars Global Surveyor (step eleven), there has never been a chance to test communications between a transmitter on the surface of Mars and an orbiter.

Step Nineteen: Spirit sleeps

Under normal conditions, the rover goes to sleep after the Odyssey pass.

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Mars Science Laboratory (Curiosity Mission)

Main Teaching Points

Show the Curiosity (MSL) landing site on the Gale Crater model and the general path being traveled by the rover.

New knowledge from the rovers and orbiting spacecraft contributes to meeting the four overarching goals of the Mars Exploration Program:

5. Determine if life ever arose on Mars,

6. Characterize the climate of Mars

7. Characterize the geology of Mars

8. Prepare for human exploration

Use PowerPoints on the Galaxy Guide Portal as well as the NASA resource binders on the cart to talk about Curiosity’s mission and highlight some of the major discoveries from the mission.

Background Information

The scientific instruments aboard Curiosity are:

Mast Camera (Mastcam)

Mars Hand Lens Imager (MAHLI)

Mars Descent Imager (MARDI)

Alpha Particle X-Ray Spectrometer (APXS)

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Chemistry & Camera (ChemCam)

Chemistry & Mineralogy X-Ray Diffraction/X-Ray Fluorescence Instrument (CheMin)

Sample Analysis at Mars (SAM) Instrument Suite

Radiation Assessment Detector (RAD)

Dynamic Albedo of Neutrons (DAN)

Rover Environmental Monitoring Station (REMS)

Mars Science Laboratory Entry Descent and Landing Instrument (MEDLI)

More information on each of the instruments can be found at:

http://mars.jpl.nasa.gov/msl/mission/instruments/

Gale Crater Adapted from mars.jpl.nasa.gov/msl/mission/timeline/prelaunch/landingsiteselection/aboutgalecrater/

At 11:32 p.m. MDT on Aug. 5, 2012, the Mars Science Laboratory rover, Curiosity,

landed on Mars at 4.5 degrees south latitude, 137.4 degrees east longitude, at the foot

of a layered mountain inside Gale Crater, within 1/3 miles of its target after a journey of

nearly 360 million miles The crater is named for Australian astronomer Walter F. Gale

(1865-1945).

Gale Crater formed when a meteor hit Mars in its early history, about 3.5 to 3.8 billion

years ago. The meteor impact punched a hole in the terrain. The explosion ejected

rocks and soil that landed around the crater. Scientists chose Gale Crater as the landing

site for Curiosity because it has many signs that water was present over its history.

Water is a key ingredient of life as we know it.

Minerals called clays and sulfates are byproducts of water. They also may preserve

signs of past life--if it existed, that is. The history of water at Gale, as recorded in its

rocks, will give Curiosity lots of clues to study as it pieces together whether Mars ever

could have been a habitat for small life forms called microbes. Gale is special because

we can see both clays and sulfate minerals, which formed in water under different

conditions.

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'Mount Sharp' on Mars Compared to Three Big Mountains on Earth

The landing site for NASA's Mars rover Curiosity was chosen for giving the mission

access to examine the lower layers of a mountain inside Gale Crater.

Gale Crater spans 96 miles (154 kilometers) in diameter and holds a mountain (which is

informally named "Mount Sharp" to pay tribute to geologist Robert P. Sharp) rising

higher from the crater floor than Mount Rainier rises above Seattle! Gale is about the

combined area of Connecticut and Rhode Island.

Curiosity landed within a landing ellipse approximately 4 miles wide and 12 miles long

(7 kilometers by 20 kilometers). The landing ellipse is about 14,400 feet (4,400 meters)

below Martian "sea level" (defined as the average elevation around the equator). The

expected near-surface atmospheric temperatures at the Gale Crater landing site during

Curiosity's primary mission (1 Martian year or 687 Earth days) are from - 130 F to 32 F

(-90 C to 0 C).

Layering in the central mound (Mount Sharp) suggests it is the surviving remnant of an

extensive sequence of deposits. Some scientists believe the crater filled in with

sediments and, over time, the relentless Martian winds carved Mount Sharp, which

today rises about 3.4 miles (5.5 kilometers) above the floor of Gale Crater--three times

higher than the Grand Canyon is deep!

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This map shows the route driven by NASA’s Curiosity Mars rover from the location

where it landed in August 2012 to its location in early March 2016, approaching a

geological waypoint called “Naukluft Plateau.”

Curiosity departed the “Gobabeb” waypoint, where it scopped samples from sand dunes

for analysis, on February 3, 2016, with a drive during the 1,243rd Martian day, or sol, of

the rover’ work on Mars.

The base image for the map is from the High Resolution Imaging Science Experiment

(HiRISE) camera on NASA’s Mars Reconnaissance Orbiter. Bagnold Dues form a band

of dar, wind-blown material at the foot of Mount Sharp.

Discoveries (as of May 2015) Adapted from http://mars.nasa.gov/msl/mission/science/results/

A Suitable Home for Life: The Curiosity rover finds that ancient Mars had the right

chemistry to support living microbes. Curiosity finds sulfur, nitrogen, oxygen,

phosphorus and carbon-- key ingredients necessary for life--in the powder sample

drilled from the "Sheepbed" mudstone in Yellowknife Bay. The sample also reveals clay

minerals and not too much salt, which suggests fresh, possibly drinkable water once

flowed there.

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Organic Carbon Found in Mars Rocks: Organic molecules are the building blocks of life,

and they were discovered on Mars after a long search by the Sample Analysis at Mars

(SAM) instrument in a powdered rock sample from the "Sheepbed" mudstone in

"Yellowknife Bay." The finding doesn't necessarily mean there is past or present life on

Mars, but it shows that raw ingredients existed for life to get started there at one time. It

also means that ancient organic materials can be preserved for us to recognize and

study today.

Present and Active Methane in Mars' Atmosphere: The Tunable Laser Spectrometer

within the SAM instrument detected a background level of atmospheric methane and

observed a ten-fold increase in methane over a two-month period. The discovery of

methane is exciting because methane can be produced by living organisms or by

chemical reactions between rock and water, for example. Which process is producing

methane on Mars? What caused the brief and sudden increase?

Radiation Could Pose Health Risks for Humans: During her trip to Mars, Curiosity

experienced radiation levels exceeding NASA's career limit for astronauts. The

Radiation Assessment Detector (RAD) instrument on Curiosity found that two forms of

radiation pose potential health risks to astronauts in deep space. One is galactic cosmic

rays (GCRs), particles caused by supernova explosions and other high-energy events

outside the solar system. The other is solar energetic particles (SEPs) associated with

solar flares and coronal mass ejections from the sun. NASA will use Curiosity's data to

design missions to be safe for human explorers

A Thicker Atmosphere and More Water in Mars' Past: The SAM instrument suite has

found Mars' present atmosphere to be enriched in the heavier forms (isotopes) of

hydrogen, carbon, and argon. These measurements indicate that Mars has lost much of

its original atmosphere and inventory of water. This loss occurred to space through the

top of the atmosphere, a process currently being observed by the MAVEN orbiter.

Curiosity Finds Evidence of An Ancient Streambed: The rocks found by Curiosity are

smooth and rounded and likely rolled downstream for at least a few miles. They look like

a broken sidewalk, but they are actually exposed bedrock made of smaller fragments

cemented together, or what geologists call a sedimentary conglomerate. They tell a

story of a steady stream of flowing water about knee deep.

More information on the latest discoveries can be found at:

http://mars.jpl.nasa.gov/msl/news/whatsnew/

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History of Landers on Mars

Main Teaching Points

Using globes, point out Mars spacecraft landing sites – Viking 1 & 2, Mars Pathfinder/Sojourner, Phoenix, Spirit and Opportunity and Curiosity. Use this as a starting point to talk about the history of robotic landers on Mars and some of the major discoveries

Background Information

Adapted from http://mars.nasa.gov/programmissions/missions/past/

Successful, or partially successful Mars Missions (up to March 2016)

Spacecraft Country Flyby Orbiter Stationar

y Lander

Rover Other

Mars 1 U.S.S.R. 1963

Mariner 4 U.S. 1965

Mariners 6 & 7 U.S. 1969

Mariner 9 U.S. 1971

Mars 2 U.S.S.R. 1971

Mars 3 U.S.S.R. 1971 1971

Mars 5 U.S.S.R. 1975

Viking 1 & 2 U.S. 1976 1976

Fobos 2 U.S.S.R. Flyby of Mars’

Moon Phobos --

1987

Mars

Pathfinder/Sojourner

U.S. 1997 1997

Mars Global

Surveyor

U.S. 1997

Mars Odyssey U.S 2001

Mars Express E.S.A. 2003

Mars Exploration

Rovers

U.S. 2004

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Mars

Reconnaissance

Orbiter

U.S. 2006

Phoenix U.S. 2008

Mars Science

Laboratory

U.S. 2012

Mars Atmosphere

and Volatile

EvolutioN (MAVEN)

U.S. 2014

Mars Orbiter Mission

(MOM)

India 2014

ExoMars Trace Gas

Orbiter with

Schiaparelli entry,

descent and landing

demonstrator

E.S.A./Russia 2016

(Enroute)

2016

(Enroute)

Viking Missions

Orbiters Launch: August 20, 1975 (Viking 1); September 9, 1975 (Viking 2) Arrival: June 19, 1976 (Viking 1); August 7, 1976 (Viking 2)

Landers Landing: July 20, 1976 (Viking 1); September 3, 1976 (Viking 2) Mass: 576 kilograms (1,270 pounds) Science instruments: Biology instrument, gas chromatograph/mass spectrometer, X-ray fluorescence spectrometer, seismometer, meteorology instrument, stereo color cameras, physical and magnetic properties of soil, aerodynamic properties and composition of Martian atmosphere with changes in altitude.

NASA's Viking Project found a place in history when it became the first U.S. mission to land a spacecraft safely on the surface of Mars and return images of the surface. Two identical spacecraft, each consisting of a lander and an orbiter, were built. Each orbiter-lander pair flew together and entered Mars orbit; the landers then separated and descended to the planet's surface.

The Viking 1 lander touched down on the western slope of Chryse Planitia (the Plains of Gold), while the Viking 2 lander settled down at Utopia Planitia.

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Besides taking photographs and collecting other science data on the Martian surface, the two landers conducted three biology experiments designed to look for possible signs of life. These experiments discovered unexpected and enigmatic chemical activity in the Martian soil, but provided no clear evidence for the presence of living microorganisms in soil near the landing sites. According to scientists, Mars is self-sterilizing. They believe the combination of solar ultraviolet radiation that saturates the surface, the extreme dryness of the soil and the oxidizing nature of the soil chemistry prevent the formation of living organisms in the Martian soil.

The Viking mission was planned to continue for 90 days after landing. Each orbiter and lander operated far beyond its design lifetime. Viking Orbiter 1 continued for four years and 1,489 orbits of Mars, concluding its mission August 7, 1980, while Viking Orbiter 2 functioned until July 25, 1978. Because of the variations in available sunlight, both landers were powered by radioisotope thermoelectric generators -- devices that create electricity from heat given off by the natural decay of plutonium. That power source allowed long-term science investigations that otherwise would not have been possible. Viking Lander 1 made its final transmission to Earth November 11, 1982. The last data from Viking Lander 2 arrived at Earth on April 11, 1980.

Pathfinder

Launch: December 4, 1996

Rover Mass: 10.6 kilograms (23 pounds) Science instruments: Alpha Proton X-ray Spectrometer, three Cameras (also technology experiments)

Mars Pathfinder was originally designed as a technology demonstration of a way to deliver an instrumented lander and a free-ranging robotic rover to the surface of the red planet. Pathfinder not only accomplished this goal but also returned an unprecedented amount of data and outlived its primary design life.

Mars Pathfinder used an innovative method of directly entering the Martian atmosphere, assisted by a parachute to slow its descent through the thin Martian atmosphere and a giant system of airbags to cushion the impact. The landing site, an ancient flood plain in Mars' northern hemisphere known as Ares Vallis, is among the rockiest parts of Mars. It was chosen because scientists believed it to be a relatively safe surface to land on and one which contained a wide variety of rocks deposited during a catastrophic flood.

The lander, formally named the Carl Sagan Memorial Station following its successful touchdown, and the rover, named Sojourner after American civil rights crusader Sojourner Truth, both outlived their design lives — the lander by nearly three times, and the rover by 12 times.

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From landing until the final data transmission on September 27, 1997, Mars Pathfinder returned 2.3 billion bits of information, including more than 16,500 images from the lander and 550 images from the rover, as well as more than 15 chemical analyses of rocks and soil and extensive data on winds and other weather factors. Findings from the investigations carried out by scientific instruments on both the lander and the rover suggest that Mars was at one time in its past warm and wet, with water existing in its liquid state and a thicker atmosphere.

For more information, see the Mars Pathfinder home page.

Planned Future Missions:

2018 -- InSight (NASA) Interior Exploration Using Seismic Investigations, Geodesy

and Heat Transport lander.

2018 -- ExoMars Rover (ESA and Russia) European Rover with ground penetrating

radar and drill and Russian stationary station. Will use ExoMars Trace Gas Orbiter

as communications relay.

2020 -- Rover (NASA) based on Curiosity and with new instruments including

ground penetrating radar and more sophisticated instrumentation.

Search for Life on Mars

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Water is key to life as we know it. Early Mars missions (2001 Mars Odyssey, Mars

Exploration Rovers (Spirit and Opportunity), Mars Reconnaissance Orbiter, Mars

Phoenix Lander) were designed to make discoveries under the previous Mars

Exploration Program science theme of "Follow the Water." Progressive discoveries

related to evidence of past and present water in the geologic record make it possible to

take the next steps toward finding evidence of life itself.

We know that Mars’ polar caps contain water ice. In 2015, NASA's Mars

Reconnaissance Orbiter (MRO) provided the strongest evidence yet that liquid water

flows intermittently on present-day Mars.

Using an imaging spectrometer on MRO, researchers detected signatures of hydrated

minerals on slopes where mysterious streaks are seen on the Red Planet. These

darkish streaks appear to ebb and flow over time. They darken and appear to flow down

steep slopes during warm seasons, and then fade in cooler seasons. They appear in

several locations on Mars when temperatures are above minus 10 degrees Fahrenheit

(minus 23 Celsius), and disappear at colder times.

The Mars Science Laboratory mission and its Curiosity rover mark a transition between

the themes of "Follow the Water" and "Seek Signs of Life." In addition to landing in a

place with past evidence of water, Curiosity has been seeking evidence of organics, the

chemical building blocks of life. Places with water and the chemistry needed for life

potentially provide habitable conditions. The Curiosity rover has found sulfur, nitrogen,

oxygen, and phosphorus and carbon-- key ingredients necessary for life--in the powder

sample drilled from the "Sheepbed" mudstone in Yellowknife Bay. The sample also

reveals clay minerals and not too much salt, which suggests fresh, possibly drinkable

water once flowed there.

Future Mars missions would likely be designed to search for life itself in places identified

as potential past or present habitats.

There are several conditions that are necessary for life:

Source of molecules from which to build its own cellular structures and for

reproduction

Source of energy to maintain biological order and to fuel the many chemical

reactions that occur in life

Liquid medium, most likely liquid water, for transporting the molecules of life

Evidence of some of these conditions have already been found on Mars.

Mars has a few potential energy sources: cosmic rays, UV rays, and volcanos (such

as Olympus Mons, pictured in the center of the Life on Mars in a Box.

In 2004, Spirit discovered the mineral goethite (upper right corner) in the Columbia

Hills region of Mars. Goethite is an iron mineral that forms only in the presence of

water (liquid, gas or solid).

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In 2011, Opportunity discovered a hydrated calcium sulfate mineral believed to be

gypsum (lower right corner) in Endeavor Crater. Scientists think this likely formed

from water dissolving calcium from volcanic rocks.

Piece of the Murchison meteorite (upper left) contains non-biological carbon in the

form of amino acids, and shows the availability of life-building molecules.

Piece of the Shergottite meteorite (lower left) from Mars, which contains non-

biological carbon created by volcanic action during the early history of Mars, shows

a second source of life-building molecules (Steele et al, Science, 2012)

The key to this puzzle is whether all these ingredients for life came together in the right

proportions at the right time.

Other Cool Stuff to Try

Show pictures from MER and MSL showing sedimentary rocks, sand dunes, actual use of RAT and the MRL’s drill and laser/spectrograph.

For young kids explain why the sun’s energy is the “rover’s breakfast”.

Using globes, point out major Mars features: Olympus Mons, Valles Marineris (canyon nearly 11 times as long and the Grand Canyon and 5 times as deep), and Hellas Planitia (the largest visible impact crater known in the Solar System).

Questions and Answers

Have we found life on Mars?

Not yet. We have found a lot of evidence of some of the chemical building blocks of life

such as water (including snow and ice) and organic carbon compounds including

methane, but so far no direct indication of life. The current atmosphere of Mars consists

of about 96% carbon dioxide, 1.93% argon and 1.89% nitrogen along with traces of

oxygen and water; not very conducive to the larger life forms as we know them on

Earth. The atmospheric pressure at the surface is only a small fraction of Earth; roughly

equal to that found 35 km (22 mi) above the earth’s sea level.

Why is Mars the color red?

Mars is known as the Red Planet because iron minerals in the Martian soil oxidize, or

rusted, causing the soil -- and the dusty atmosphere -- to look red.

How do we drive the rovers?

Unfortunately, there is no joystick for driving a Mars rover. Due to the long distances

between earth and Mars, radio communications take between 4-5 minutes, so

everything needs to be planned in advance. Before a rover “hits the road,” engineers

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send computer commands overnight, telling it where to go the next day. Depending on

how tricky the terrain is, rover drivers have two options.

They can send a string of specific commands like: “Drive forward 5 meters; then turn

right 90 degrees.” The rover turns its wheels enough times to add up to 5 meters, then

turns in place.

Or if it looks safe, they can let the rover think on its own. They write commands like:

“See that rock over there? Find your way there safely.” Then, using two cameras like

human eyes, the rover gets a 3D view of hazards such as large rocks and steep slopes.

After mapping the danger zones, it plots the safest route to avoid them.

Either way, engineers always check to see if the rover completed its drive as planned.

Using the rover’s cameras to check, engineers then verity the rover’s new location.

How do we communicate with the rovers?

The NASA Deep Space Network (DSN) of large dish antennas provides the primary link

to the rovers.

Not only can the rovers send messages directly to the DSN stations, but they can uplink

information to other spacecraft orbiting Mars. The 2001 Mars Odyssey, Mars Global

Surveyor and MAVEN orbiters act as relays that can pass along news to and from Earth

for the rovers. The European Space Agency’s ExoMars orbiter, currently enroute to

Mars, will also have this capability.

The orbiting spacecraft are closer to the rovers than the DSN antennas on Earth and

require less rover signal energy. The orbiters have Earth in their field of view for much

longer time periods than the rovers on the ground.

Expected to have a lifetime of only 90 days, why is Opportunity still operating

after 12 years on the surface?

The designers of Opportunity and Spirit anticipated that fine dust would eventually limit

the power generated from the rovers’ solar panels, reducing and ending the power

source for the spacecraft. Unexpectedly the Mars winds and “dust devils” have

periodically swept much of the dust from the solar panels.

What do the colors on the two Mars globes represent?

The red-colored globe shows the true color of Mars. The multi-colored globe shows the

topography of Mars with the colors representing elevations of the terrain. Blue is the

lowest, then green, red, brown and finally white showing the highest elevation.

Why do rovers have multiple wheels?

Opportunity has six wheels, each with its own individual motor. The two front and two

rear wheels also have individual steering motors (1 each). This steering capability

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allows the vehicle to turn in place, a full 360 degrees. The 4-wheel steering also allows

the rover to swerve and curve, making arching turns. The 6 wheel design, along with

the “rocker” suspension allows the rover body to be balanced as it moves over rocks

and uneven ground and through sandy patches.

How fast do the rovers go?

Opportunity has a top speed on flat hard ground of 4-5 centimeters (2 inches) per

second. However, in order to ensure a safe drive, the rover is equipped with hazard

avoidance software that causes the rover to stop and reassess its location every few

seconds. So, over time, the vehicle achieves an average speed of 1 centimeter per

second. The rover is programmed to drive for roughly 10 seconds, then stop to observe

and understand the terrain it has driven into for 20 seconds, before moving safely

onward for another 10 seconds. It has moved up to 140 meters (460 ft.) in one day.

How long does it take to get to Mars?

The total journey time from Earth to Mars takes between 150-300 days depending on

the speed of the launch, the alignment of Earth and Mars, and the length of the journey

the spacecraft takes to reach its target. Mars and Earth are traveling at different speeds

and distances in their orbits around the sun. You can’t point a rocket at Mars because

by the time you got there, Mars would have already moved. Instead, spacecraft

launched from Earth need to be pointed at where Mars is going to be.

It also depends on how much fuel you’re willing to burn to get there. More fuel, shorter

travel time. NASA engineers use a method of travel called a Hohmann Transfer Orbit –

or a Minimum Energy Transfer Orbit – to send a spacecraft from Earth to Mars with the

least amount of fuel possible. With this method you boost the orbit of your spacecraft

so that it’s following a larger orbit around the Sun than the Earth. Eventually that orbit

will intersect the orbit of Mars – at the exact moment that Mars is there too.

About every 26 months (2.1 years) an optimum launch window presents itself and it is

during this time that any spacecraft traveling to Mars are launched.

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Background materials (websites, videos, articles, digital collections links, etc.)

Mars Facts and Mars Exploration:

http://solarsystem.nasa.gov/planets/profile.cfm?Object=Mars

http://mars.jpl.nasa.gov/

http://science.nasa.gov/about-us/smd-programs/mars-exploration/

http://exploration.esa.int/mars/

Pathfinder/Sojouner:

http://solarsystem.nasa.gov/missions/profile.cfm?Sort=Target&Target=Mars&MCode

=Pathfinder&Display=ReadMore

Mars Exploration Rovers (Opportunity and Spirit):

http://mars.nasa.gov/mer/home/index.html

http://www.nasa.gov/mission_pages/mer/index.html#.VND5LS7lxmg

http://www.jpl.nasa.gov/missions/details.php?id=5909

http://www.jpl.nasa.gov/missions/details.php?id=5917

Mars Science Lab (Curiosity):

http://mars.nasa.gov/msl/mission/overview/

http://www.nasa.gov/mission_pages/msl/index.html#.VND5li7lxmg

http://www.jpl.nasa.gov/missions/mars-science-laboratory-curiosity-rover-msl/

ESA ExoMars:

http://www.esa.int/Our_Activities/Space_Science/ExoMars

Trajectory to Mars:

https://www.youtube.com/watch?v=Js0Io4qJT4c&feature=youtube_gdata

https://solarsystem.nasa.gov/basics/bsf4-1.php

http://www.phy6.org/stargaze/Smars1.htm