TERM PAPER on Space Craft

7/27/2019 TERM PAPER on Space Craft

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TERM PAPER

PHY101: MECHANICSTopic: SPACE CRAFT

DOA: 26.08.2010

DOR: 22.09.2010

DOS: 10.11.2010

Submitted to: Submitted by:

Ms. Neeti Walia Mr.SAURABH MADEEL

Dept.of physics Roll no- B32

Reg.no-11003133


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ACKNOWLEDGEMENT:I take this opportunity to present my votes of thanks to all those guidepost who really

acted as lightening pillars to enlighten our way throughout this project that has led tosuccessful and satisfactory completion of this study.

We are really grateful to our HOD for providing us with an opportunity to undertakethis project in this university and providing us with all the facilities. We are highlythankful to Miss Neeti Walia for her active support, valuable time and advice, whole-hearted guidance, sincere cooperation and pains-taking involvement during the study andin completing the assignment of preparing the said project within the time stipulated,lastly.

We are thankful to all those, particularly the various friends , who have beeninstrumental in creating proper, healthy and conductive environment and including newand fresh innovative ideas for us during the project, their help, it would have beenextremely difficult for us to prepare the project in a time bound framework.

Name-SAURABH MADEEL

Regd.No-11003133

Roll no:- RE4001B32


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TABLE OF CONTENTS:


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INTRODUCTION :-

A spacecraft is a craft or machine designed for spaceflight. Spacecraft are used for a varietyof purposes, including communications, earth observation, meteorology, navigation,

planetary exploration and space tourism. Spacecraft and space travel are common themes inworks of science fiction.

On a sub-orbital spaceflight, a spacecraft enters space and then returns to the surface, withouthaving gone into an orbit. For orbital spaceflights, spacecraft enter closed orbits around theEarth or around other celestial bodies. Spacecraft used for human spaceflight carry people on

board as crew or passengers, while those used for robotic space missions operate either autonomously or telerobotically. Robotic spacecraft used to support scientific research arespace probes. Robotic spacecraft that remain in orbit around a planetary body are artificialsatellites. Only a handful of interstellar probes, such as Pioneer 10 and 11, Voyager 1 and 2 ,and New Horizons, are currently on trajectories that leave our Solar System.

DEFINITION OF SPACE CRAFT:-

Spacecraft is the collective name of devices, which are designed to be placed into space,comprising earth satellites, interplanetary and trans-solar types of space probes. Spacecraftcan be manned or unmanned.
http://en.wikipedia.org/wiki/Craft_(vehicle)http://en.wikipedia.org/wiki/Spaceflighthttp://en.wikipedia.org/wiki/Telecommunicationshttp://en.wikipedia.org/wiki/Earth_observation_satellitehttp://en.wikipedia.org/wiki/Weather_satellitehttp://en.wikipedia.org/wiki/Navigationhttp://en.wikipedia.org/wiki/Planetary_sciencehttp://en.wikipedia.org/wiki/Space_tourismhttp://en.wikipedia.org/wiki/Spaceflighthttp://en.wikipedia.org/wiki/Science_fictionhttp://en.wikipedia.org/wiki/Sub-orbital_spaceflighthttp://en.wikipedia.org/wiki/Outer_spacehttp://en.wikipedia.org/wiki/Orbithttp://en.wikipedia.org/wiki/Orbital_spaceflighthttp://en.wikipedia.org/wiki/Closed_orbithttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Astronomical_objecthttp://en.wikipedia.org/wiki/Human_spaceflighthttp://en.wikipedia.org/wiki/Robotic_space_missionhttp://en.wikipedia.org/wiki/Autonomous_robothttp://en.wikipedia.org/wiki/Teleroboticshttp://en.wikipedia.org/wiki/Space_probehttp://en.wikipedia.org/wiki/Satellitehttp://en.wikipedia.org/wiki/Interstellar_probehttp://en.wikipedia.org/wiki/Pioneer_10http://en.wikipedia.org/wiki/Pioneer_11http://en.wikipedia.org/wiki/Voyager_1http://en.wikipedia.org/wiki/Voyager_2http://en.wikipedia.org/wiki/New_Horizonshttp://en.wikipedia.org/wiki/Solar_Systemhttp://en.wikipedia.org/wiki/Solar_Systemhttp://en.wikipedia.org/wiki/New_Horizonshttp://en.wikipedia.org/wiki/Voyager_2http://en.wikipedia.org/wiki/Voyager_1http://en.wikipedia.org/wiki/Pioneer_11http://en.wikipedia.org/wiki/Pioneer_10http://en.wikipedia.org/wiki/Interstellar_probehttp://en.wikipedia.org/wiki/Satellitehttp://en.wikipedia.org/wiki/Space_probehttp://en.wikipedia.org/wiki/Teleroboticshttp://en.wikipedia.org/wiki/Autonomous_robothttp://en.wikipedia.org/wiki/Robotic_space_missionhttp://en.wikipedia.org/wiki/Human_spaceflighthttp://en.wikipedia.org/wiki/Astronomical_objecthttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Closed_orbithttp://en.wikipedia.org/wiki/Orbital_spaceflighthttp://en.wikipedia.org/wiki/Orbithttp://en.wikipedia.org/wiki/Outer_spacehttp://en.wikipedia.org/wiki/Sub-orbital_spaceflighthttp://en.wikipedia.org/wiki/Science_fictionhttp://en.wikipedia.org/wiki/Spaceflighthttp://en.wikipedia.org/wiki/Space_tourismhttp://en.wikipedia.org/wiki/Planetary_sciencehttp://en.wikipedia.org/wiki/Navigationhttp://en.wikipedia.org/wiki/Weather_satellitehttp://en.wikipedia.org/wiki/Earth_observation_satellitehttp://en.wikipedia.org/wiki/Telecommunicationshttp://en.wikipedia.org/wiki/Spaceflighthttp://en.wikipedia.org/wiki/Craft_(vehicle)


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HISTORY:

Spacecraft propulsion is based on jet propulsion as used by rocket motors. The principle of rocket propulsion was known as far back as 360B.C. In the 13th century solid rocket powered

arrows were used by the Chinese military.The Second World War and the cold war advanced rocket missile development in moderntime. Later, space opened up to exploration and commercial exploitation by satellites androbot spacecraft.

SPACE CRAFT DESIGN:

The design of spacecraft covers a broad area, including the design of both robotic spacecraft(satellites and planetary probes) , and spacecraft for human spaceflight (spaceships and spacestations) . The design of spacecraft is somewhat related to the design of rockets and missiles. Spacecraft design brings together aspects of various disciplines, namely:

Astronautics Systems engineering Communications engineering Computer engineering Software engineering Electrical engineering Control theory Thermal engineering Propulsion Mechanical engineering

SUBSYSTEMS :

A spacecraft system comprises various subsystems, dependent upon mission profile.Spacecraft subsystems comprise the spacecraft " bus" and may include: attitude determinationand control (variously called ADAC, ADC or ACS), guidance, navigation and control (GNCor GN&C), communications (Comms), command and data handling (CDH or C&DH), power
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(EPS), thermal control (TCS), propulsion, and structures. Attached to the bus are typically payloads.

1. LIFE SUPPORT:

Spacecraft intended for human spaceflight must also include a life support system for thecrew.

In human spaceflight, the life support system is a group of devices that allow a human beingto survive in outer space. NASA often uses the phrase Environmental Control and LifeSupport System or the acronym ECLSS when describing these systems for its humanspaceflight missions. The life support system may supply air, water and food. It must alsomaintain the correct body temperature, an acceptable pressure on the body and deal with the

body's waste products. Shielding against harmful external influences such as radiation andmicro-meteorites may also be necessary. Components of the life support system are life-critical, and are designed and constructed using safety engineering techniques.

2. ATTITUDE CONTROL:

A Spacecraft needs an attitude control subsystem to be correctly oriented in space andrespond to external torques and forces properly. The attitude control subsystem consists of sensors and actuators, together with controlling algorithms. The attitude control subsystem

permits proper pointing for the science objective, sun pointing for power to the solar arraysand earth-pointing for communications.The attitude of a vehicle is its orientation with respectto a defined frame of reference.

Attitude dynamics is the modeling of the changing position and orientation of a vehicle, dueto external forces acting on the body. Attitude control is the purposeful manipulation of controllable external forces (using vehicle actuators) to establish a desired attitude, whereasattitude determination is the utilization of vehicle sensors to ascertain the current vehicleattitude.

Mathematical and physical treatment of the basic aspects of these topics is well-developed, but the field is quite active with respect to advanced topics and applications.

Attitude control is the exercise of control over the orientation of an object with respect to aninertial frame of reference or another entity (the celestial sphere, certain fields, nearbyobjects, ...).
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Controlling vehicle attitude requires sensors to measure vehicle attitude, actuators to applythe torques needed to re-orient the vehicle to a desired attitude, and algorithms to commandthe actuators based on:

(1) sensor measurements of the current attitude and (2) specification of a desired attitude.

The integrated field that studies the combination of sensors, actuators and algorithms is calledGuidance, Navigation and Control (GNC).

3. GNC:

Guidance refers to the calculation of the commands (usually done by the CDH subsystem)needed to steer the spacecraft where it is desired to be. Navigation means determining aspacecraft's orbital elements or position. Control means adjusting the path of the spacecraft tomeet mission requirements. On some missions, GNC and Attitude Control are combined intoone subsystem of the spacecraft.

4. COMMAND AND DATA HANDLING:

The CDH subsystem receives commands from the communications subsystem, performsvalidation and decoding of the commands, and distributes the commands to the appropriatespacecraft subsystems and components. The CDH also receives housekeeping data andscience data from the other spacecraft subsystems and components, and packages the data for storage on a data recorder or transmission to the ground via the communications subsystem.Other functions of the CDH include maintaining the spacecraft clock and state-of-healthmonitoring.

5. POWER:

Spacecraft need an electrical power generation and distribution subsystem for powering thevarious spacecraft subsystems. For spacecraft near the Sun, solar panels are frequently usedto generate electrical power. Spacecraft designed to operate in more distant locations, for example Jupiter, might employ a Radioisotope Thermoelectric Generator (RTG) to generate

electrical power. Electrical power is sent through power conditioning equipment before it passes through a power distribution unit over an electrical bus to other spacecraftcomponents. Batteries are typically connected to the bus via a battery charge regulator, andthe batteries are used to provide electrical power during periods when primary power is notavailable, for example when a Low Earth Orbit (LEO) spacecraft is eclipsed by the Earth.

6. THERMAL CONTROL:

Spacecraft must be engineered to withstand transit through the Earth's atmosphere and the

space environment. They must operate in a vacuum with temperatures potentially rangingacross hundreds of degrees Celsius as well as (if subject to reentry) in the presence of
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plasmas. Material requirements are such that either high melting temperature, low densitymaterials such as beryllium and reinforced carbon-carbon or (possibly due to the lower thickness requirements despite its high density) tungsten or ablative carbon/carboncomposites are used. Depending on mission profile, spacecraft may also need to operate onthe surface of another planetary body. The thermal control subsystem can be passive,

dependent on the selection of materials with specific radiative properties. Active thermalcontrol makes use of electrical heaters and certain actuators such as louvers to controltemperature ranges of equipments within specific ranges.

7. PROPULSION:

Spacecraft may or may not have a propulsion subsystem, depending upon whether or not themission profile calls for propulsion. The Swift spacecraft is an example of a spacecraft thatdoes not have a propulsion subsystem. Typically though, LEO spacecraft (for example Terra(EOS AM-1) include a propulsion subsystem for altitude adjustments (called drag make-upmaneuvers) and inclination adjustment maneuvers. A propulsion system is also needed for spacecraft that perform momentum management maneuvers. Components of a conventional

propulsion subsystem include fuel, tankage, valves, pipes, and thrusters. The TCS interfaceswith the propulsion subsystem by monitoring the temperature of those components, and by

preheating tanks and thrusters in preparation for a spacecraft maneuver.

SOME IMPORTANT POINTS IN PROPULSION:

a. SPACECRAFT PROPULSION:

Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. There are many different methods. Each method has drawbacks and advantages, andspacecraft propulsion is an active area of research. However, most spacecraft today are

propelled by forcing a gas from the back/rear of the vehicle at very high speed through asupersonic de Laval nozzle. This sort of engine is called a rocket engine.

All current spacecraft use chemical rockets (bipropellant or solid-fuel) for launch, thoughsome (such as the Pegasus rocket and SpaceShipOne) have used air-breathing engines ontheir first stage. Most satellites have simple reliable chemical thrusters (often monopropellantrockets) or resistojet rockets for orbital station-keeping and some use momentum wheels for attitude control. Soviet bloc satellites have used electric propulsion for decades, and newer Western geo-orbiting spacecraft are starting to use them for north-south stationkeeping.

Interplanetary vehicles mostly use chemical rockets as well, although a few have used ionthrusters and Hall effect thrusters (two different types of electric propulsion) to great success.

b. NEED:

Artificial satellites must be launched into orbit, and once there they must be placed in their nominal orbit. Once in the desired orbit, they often need some form of attitude control so thatthey are correctly pointed with respect to the Earth, the Sun, and possibly some astronomical

object of interest. They are also subject to drag from the thin atmosphere, so that to stay inorbit for a long period of time some form of propulsion is occasionally necessary to make
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small corrections (orbital station keeping) . Many satellites need to be moved from one orbitto another from time to time, and this also requires propulsion. A satellite's useful life is over once it has exhausted its ability to adjust its orbit.

Spacecraft designed to travel further also need propulsion methods. They need to be launched

out of the Earth's atmosphere just as satellites do. Once there, they need to leave orbit andmove around.

For interplanetary travel, a spacecraft must use its engines to leave Earth orbit. Once it hasdone so, it must somehow make its way to its destination. Current interplanetary spacecraftdo this with a series of short-term trajectory adjustments. In between these adjustments, thespacecraft simply falls freely along its trajectory. The most fuel-efficient means to move fromone circular orbit to another is with a Hohmann transfer orbit: the spacecraft begins in aroughly circular orbit around the Sun. A short period of thrust in the direction of motionaccelerates or decelerates the spacecraft into an elliptical orbit around the Sun which istangential to its previous orbit and also to the orbit of its destination. The spacecraft fallsfreely along this elliptical orbit until it reaches its destination, where another short period of thrust accelerates or decelerates it to match the orbit of its destination. Special methods suchas aerobraking are sometimes used for this final orbital adjustment.

Some spacecraft propulsion methods such as solar sails provide very low but inexhaustiblethrust; an interplanetary vehicle using one of these methods would follow a rather differenttrajectory, either constantly thrusting against its direction of motion in order to decrease itsdistance from the Sun or constantly thrusting along its direction of motion to increase itsdistance from the Sun. The concept has been successfully tested by the Japanese IKAROSsolar sail spacecraft.

Spacecraft for interstellar travel also need propulsion methods. No such spacecraft has yet been built, but many designs have been discussed. Since interstellar distances are very great,a tremendous velocity is needed to get a spacecraft to its destination in a reasonable amountof time. Acquiring such a velocity on launch and getting rid of it on arrival will be aformidable challenge for spacecraft designers.

c. EFFECTIVENESS:

When in space, the purpose of a propulsion system is to change the velocity, or v, of aspacecraft. Since this is more difficult for more massive spacecraft, designers generally

discuss momentum, mv. The amount of change in momentum is called impulse. So the goalof a propulsion method in space is to create an impulse.

When launching a spacecraft from the Earth, a propulsion method must overcome a higher gravitational pull to provide a net positive acceleration. In orbit, any additional impulse, evenvery tiny, will result in a change in the orbit path.

The rate of change of velocity is called acceleration, and the rate of change of momentum iscalled force. To reach a given velocity, one can apply a small acceleration over a long periodof time, or one can apply a large acceleration over a short time. Similarly, one can achieve agiven impulse with a large force over a short time or a small force over a long time. This

means that for maneuvering in space, a propulsion method that produces tiny accelerations but runs for a long time can produce the same impulse as a propulsion method that produces
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large accelerations for a short time. When launching from a planet, tiny accelerations cannotovercome the planet's gravitational pull and so cannot be used.

The Earth's surface is situated fairly deep in a gravity well. The escape velocity required toget out of it is 11.2 kilometers/second. As human beings evolved in a gravitational field of 1g

(9.8 m/s), an ideal propulsion system would be one that provides a continuous accelerationof 1g (though human bodies can tolerate much larger accelerations over short periods). Theoccupants of a rocket or spaceship having such a propulsion system would be free from allthe ill effects of free fall, such as nausea, muscular weakness, reduced sense of taste, or leeching of calcium from their bones.

The law of conservation of momentum means that in order for a propulsion method to changethe momentum of a space craft it must change the momentum of something else as well. Afew designs take advantage of things like magnetic fields or light pressure in order to changethe spacecraft's momentum, but in free space the rocket must bring along some mass toaccelerate away in order to push itself forward. Such mass is called reaction mass.

In order for a rocket to work, it needs two things: reaction mass and energy. The impulse provided by launching a particle of reaction mass having mass m at velocity v is mv. But this particle has kinetic energy mv/2, which must come from somewhere. In a conventional solid, liquid, or hybrid rocket, the fuel is burned, providing the energy, and the reaction productsare allowed to flow out the back, providing the reaction mass. In an ion thruster, electricity isused to accelerate ions out the back. Here some other source must provide the electricalenergy (perhaps a solar panel or a nuclear reactor) , while the ions provide the reaction mass.

When discussing the efficiency of a propulsion system, designers often focus on effectivelyusing the reaction mass. Reaction mass must be carried along with the rocket and isirretrievably consumed when used. One way of measuring the amount of impulse that can beobtained from a fixed amount of reaction mass is the specific impulse, the impulse per unitweight-on-Earth (typically designated by Isp). The unit for this value is seconds. Since theweight on Earth of the reaction mass is often unimportant when discussing vehicles in space,specific impulse can also be discussed in terms of impulse per unit mass. This alternate formof specific impulse uses the same units as velocity (e.g. m/s), and in fact it is equal to theeffective exhaust velocity of the engine (typically designated ve). Confusingly, both valuesare sometimes called specific impulse. The two values differ by a factor of gn, the standardacceleration due to gravity 9.80665 m/s ( Ispgn = v e).

A rocket with a high exhaust velocity can achieve the same impulse with less reaction mass.However, the energy required for that impulse is proportional to the exhaust velocity, so thatmore mass-efficient engines require much more energy, and are typically less energyefficient. This is a problem if the engine is to provide a large amount of thrust. To generate alarge amount of impulse per second, it must use a large amount of energy per second. Sohigh-mass-efficient - engines require enormous amounts of energy per second to producehigh thrusts. As a result, most high-mass-efficient engine designs also provide lower thrustdue to the unavailability of high amounts of energy.
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d. METHODS:

Propulsion methods can be classified based on their means of accelerating the reaction mass.There are also some special methods for launches, planetary arrivals, and landings.

Reaction engines Delta-v and propellant Power use and propulsive efficiency Power to thrust ratio Rocket engines Electromagnetic propulsion

8. STRUCTURES:

Spacecraft must be engineered to withstand launch loads imparted by the launch vehicle, andmust have a point of attachment for all the other subsystems. Depending upon mission profile, the structural subsystem might need to withstand loads imparted by entry into theatmosphere of another planetary body, and landing on the surface of another planetary body.

9. GROUND SEGMENT:

The ground segment, though not technically part of the spacecraft, is vital to the operation of the spacecraft. Typical components of a ground segment in use during normal operationsinclude a mission operations facility where the flight operations team conducts the operationsof the spacecraft, a data processing and storage facility, ground stations to radiate signals to

and receive signals from the spacecraft, and a voice and data communications network toconnect all mission elements.

10. LAUNCH VEHICAL:

The launch vehicle is used to propel the spacecraft from the Earth's surface, through theatmosphere, and into an orbit, the exact orbit being dependent upon mission configuration.The launch vehicle may be expendable or reusable. In spaceflight, a launch vehicle or carrier rocket is a rocket used to carry a payload from the Earth's surface into outer space. A launchsystem includes the launch vehicle, the launch pad and other infrastructure. Usually the

payload is an artificial satellite placed into orbit, but some spaceflights are sub-orbital whileothers enable spacecraft to escape Earth orbit entirely. A launch vehicle which carries its

payload on a suborbital trajectory is often called a sounding rocket.

11. PAYLOAD:

The payload is dependent upon the mission of the spacecraft, and is typically regardedas the part of the spacecraft "that pays the bills". Typical payloads could include
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scientific instruments (cameras, telescopes, or particle detectors, for example), cargo,or a human crew.

In military aircraft or space exploration, the payload is the carrying capacity of anaircraft or space ship, including cargo, munitions, scientific instruments or experiments. External fuel, when optionally carried, is also considered part of the

payload.

The fraction of payload to the total liftoff weight of the air or spacecraft is known asthe "payload fraction" . When the weight of the payload and fuel are consideredtogether, it is known as the "useful load fraction ". In spacecraft, "mass fraction" isnormally used, which is the ratio of payload to everything else, including the rocketstructure.

0

For a rocket the payload can be a spacecraft launched with the rocket, or in the case of a ballistic missile, the warheads. Compare the throw-weight, which includes more than thewarheads.

Examples

Examples of payload capacity:

Antonov An-225: 250,000 kg Saturn V:

o Payload to Low Earth Orbit 118,000 kgo Payload to Lunar orbit 47,000 kg

Space Shuttle: o Payload to Low Earth Orbit 24,400 kg (53,700 lb)o Payload to geostationary transfer orbit 3,810 kg (8,390 lb)

Trident missile: 2800 kg
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Automated Transfer Vehicle

Payload : 16,900 lb 8 racks with 2 x 0.314 m3 and 2 x 0.414 m3

o Envelope: each 1.146 m3 in front of 4 of these 8 rackso Cargo mass: Dry cargo: 1,500 - 5,500 kgo Water: 0 - 840 kgo Gas (Nitrogen, Oxygen, air, 2 gases/flight): 0 - 100 kgo ISS Refueling propellant: 0 - 860 kg (306 kg of fuel, 554 kg of oxidizer)o ISS re-boost and attitude control propellant: 0 - 4,700kg

Total cargo upload capacity: 7,667 kg

PAYLOAD CONSTRAINTS:

Launch and transport system differ not only on the payload that can be carried but also in thestresses and other factors placed on the payload. The payload must not only be lifted to itstarget, it must also arrive safely, whether elsewhere on the surface of the Earth or a specificorbit. To ensure this the payload, such as a warhead or satellite, is designed to withstandcertain amounts of various types of "punishment" on the way to its destination. The variousconstraints placed on the launch system can be roughly categorized into those that cause

physical damage to the payload and those that can damage its electronic or chemical makeup.

Examples of physical damage include extreme accelerations over short time scales caused byatmospheric buffeting or oscillations, extreme accelerations over longer time scales caused byrocket thrust and gravity, and sudden changes in the magnitude or direction of theacceleration caused by how quick engines are throttled and shut down, etc. Damage toelectrical or chemical/biological payloads can be sustained through things such as extremetemperatures (hot or cold), rapid changes in temperature, rapid pressure changes, contact withfast moving air air streams causing ionization, and radiation exposure from cosmic rays, theVan-Allen Belts, solar wind, etc.

TYPES OF LAUNCH VEHICAL:

Expendable launch vehicles are designed for one-time use. They usually separate from their payload, and may break up during atmospheric re-entry. Reusable launch vehicles, on theother hand, are designed to be recovered intact and used again for subsequent launches. For orbital spaceflights, the Space Shuttle is currently the only launch vehicle with componentswhich have been used for multiple flights. Non-rocket space launch alternatives are at the

planning stage.

Launch vehicles are often characterized by the amount of mass they can lift into orbit. For example, a Proton rocket has a launch capacity of 22,000 kilograms (49,000 lb) into low
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Earth orbit (LEO). Launch vehicles are also characterized by the number of stages theyemploy. Rockets with as many as five stages have been successfully launched, and there have

been designs for several single-stage-to-orbit vehicles. Additionally, launch vehicles are veryoften supplied with boosters, which supply high thrust early on in the flight, and normally in

parallel with other engines on the vehicle. Boosters allow the remaining engines to be

smaller, which reduces the burnout mass of later stages, and thus allows for larger payloads.

VEHICAL ASSEMBLY:

Various methods are used to move an assembled launch vehicle onto its launch pad, eachmethod with its own specialized equipment. These assembly activities take place as part of the overall launch campaign for the vehicle. In some launch systems, like the Delta II, thevehicle is assembled vertically on the pad, using a crane to hoist each stage into place. TheSpace Shuttle orbiter, including its external tank, and solid rocket boosters, are assembledvertically in NASA' s Vehicle Assembly Building, and then a special crawler-transporter moves the entire stack to the launch pad while it is in an upright position. In contrast, theSoyuz rocket is assembled horizontally in a processing hangar, transported horizontally, andthen brought upright once at the pad.

DERIVATION AND RELATED TERMS:

In the English language, the phrase carrier rocket was used earlier, and still is occasionally, inBritain. A translation of that phrase is used in German, Russian, and Chinese. In the 1950s,the US Air Force disliked the term carrier due to the competitive nature of their relationshipwith the US Navy and their high profile operation of aircraft carriers. As an alternative,Project Vanguard provided a contraction of the phrase "Satellite Launching Vehicle"abbreviated to "SLV". This provided a term in the list of what the rockets were allocated for:flight test, or actually launching a satellite. The contraction would also apply to rockets whichsend probes to other worlds or the interplanetary medium.

ORBITAL LAUNCH VEHICALS:

Sounding rockets are normally used for brief, inexpensive space and microgravityexperiments. Current human-rated suborbital launch vehicles include SpaceShipOne and the

upcoming Space Ship Two, among others.

The delta-v needed for orbital launch is generally between 7,600 and 8,000 metres per second(25,000 and 26,000 ft/s), although there is no upper limit. How much delta-v is needed can bedetermined by using a combination of air-drag, which is determined by ballistic coefficient, gravity losses, altitude gain and the horizontal speed necessary to give a suitable perigee. Thedelta-v required for altitude gain varies, but is around 2 kilometres per second (1.2 mi/s) for 200 kilometres (120 mi) altitude.

Minimising air-drag entails having a reasonably high ballistic coefficient, which generallymeans having a launch vehicle that is about 10 20 metres (33 66 ft) long. Vehicles which

use hydrogen fueled stages should be even longer, since hydrogen has such low density.Leaving the atmosphere as early on in the flight as possible provides an air drag of around
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300 metres per second (980 ft/s). The horizontal speed necessary to achieve low earth orbit isaround 7,800 metres per second (26,000 ft/s).

The calculation of the total delta-v for launch is complicated, and in nearly all casesnumerical integration is used; adding multiple delta-v values provides a pessimistic result,

since the rocket can thrust while at an angle in order to reach orbit, thereby saving fuel as itcan gain altitude and horizontal speed simultaneously

REGULATION:

Under international law, the nationality of the owner of a launch vehicle determines whichcountry is responsible for any damages resulting from that vehicle. Due to this, some

countries require that rocket manufacturers and launchers adhere to specific regulations inorder to indemnify and protect the safety of people and property that may be affected by aflight.

In the US, any rocket launch that is not classified as amateur, and also is not "for and by thegovernment," must be approved by the Federal Aviation Administration' s Office of Commercial Space Transportation (FAA/AST), located in Washington, DC

REUSABLE VESSELS:

The first reusable spacecraft, the X-15, was air-launched on a suborbital trajectory on July 19,1963. The first partially reusable orbital spacecraft, the Space Shuttle, was launched by theUSA on the 20th anniversary of Yuri Gagarin' s flight, on April 12, 1981. During the Shuttleera, six orbiters were built, all of which have flown in the atmosphere and five of which haveflown in space. The Enterprise was used only for approach and landing tests, launching fromthe back of a Boeing 747 and gliding to deadstick landings at Edwards AFB, California. Thefirst Space Shuttle to fly into space was the Columbia, followed by the Challenger, Discovery, Atlantis, and Endeavour. The Endeavour was built to replace the Challenger whenit was lost in January 1986. The Columbia broke up during re-entry in February 200

The first automatic partially reusable spacecraft was the Buran (Snowstorm), launched by the

USSR on November 15, 1988, although it made only one flight. This spaceplane wasdesigned for a crew and strongly resembled the U.S. Space Shuttle, although its drop-off
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boosters used liquid propellants and its main engines were located at the base of what would be the external tank in the American Shuttle. Lack of funding, complicated by the dissolutionof the USSR, prevented any further flights of Buran. The Space Shuttle has since beenmodified to allow for autonomous re-entry via the addition of a control cable running fromthe control cabin to the mid-deck which would allow for the automated deployment of the

landing gear in the event a un-crewed re-entry was required following abandonment due todamage at the ISS.

Per the Vision for Space Exploration, the Space Shuttle is due to be retired in 2010 duemainly to its old age and high cost of program reaching over a billion dollars per flight. TheShuttle's human transport role is to be replaced by the partially reusable Crew ExplorationVehicle (CEV) no later than 2014. The Shuttle's heavy cargo transport role is to be replaced

by expendable rockets such as the Evolved Expendable Launch Vehicle (EELV) or a ShuttleDerived Launch Vehicle.

Scaled Composites' Space Ship One was a reusable suborbital spaceplane that carried pilotsMike Melvill and Brian Binnie on consecutive flights in 2004 to win the Ansari X Prize. TheSpaceship Company will build its successor Space Ship Two. A fleet of Space Ship Twosoperated by Virgin Galactic should begin reusable private spaceflight carrying paying

passengers in 2011.

( The Apollo 15 Command/Service Module as viewed from the Lunar Module on August 2, 1971)

REFRENCE:

1. Efunda.com2. Wikipedia.com3. hus.parkingspa.com4. scientificamerican.com5. spacecraft.com6. nationalgeographic.com
http://en.wikipedia.org/wiki/Vision_for_Space_Explorationhttp://en.wikipedia.org/wiki/Crew_Exploration_Vehiclehttp://en.wikipedia.org/wiki/Crew_Exploration_Vehiclehttp://en.wikipedia.org/wiki/Evolved_Expendable_Launch_Vehiclehttp://en.wikipedia.org/wiki/Shuttle_Derived_Launch_Vehiclehttp://en.wikipedia.org/wiki/Shuttle_Derived_Launch_Vehiclehttp://en.wikipedia.org/wiki/Scaled_Compositeshttp://en.wikipedia.org/wiki/SpaceShipOnehttp://en.wikipedia.org/wiki/Spaceplanehttp://en.wikipedia.org/wiki/Mike_Melvillhttp://en.wikipedia.org/wiki/Brian_Binniehttp://en.wikipedia.org/wiki/Ansari_X_Prizehttp://en.wikipedia.org/wiki/The_Spaceship_Companyhttp://en.wikipedia.org/wiki/The_Spaceship_Companyhttp://en.wikipedia.org/wiki/SpaceShipTwohttp://en.wikipedia.org/wiki/Virgin_Galactichttp://en.wikipedia.org/wiki/Private_spaceflighthttp://en.wikipedia.org/wiki/Apollo_15http://en.wikipedia.org/wiki/Lunar_Modulehttp://hus.parkingspa.com/http://hus.parkingspa.com/http://en.wikipedia.org/wiki/Lunar_Modulehttp://en.wikipedia.org/wiki/Apollo_15http://en.wikipedia.org/wiki/Private_spaceflighthttp://en.wikipedia.org/wiki/Virgin_Galactichttp://en.wikipedia.org/wiki/SpaceShipTwohttp://en.wikipedia.org/wiki/The_Spaceship_Companyhttp://en.wikipedia.org/wiki/The_Spaceship_Companyhttp://en.wikipedia.org/wiki/Ansari_X_Prizehttp://en.wikipedia.org/wiki/Brian_Binniehttp://en.wikipedia.org/wiki/Mike_Melvillhttp://en.wikipedia.org/wiki/Spaceplanehttp://en.wikipedia.org/wiki/SpaceShipOnehttp://en.wikipedia.org/wiki/Scaled_Compositeshttp://en.wikipedia.org/wiki/Shuttle_Derived_Launch_Vehiclehttp://en.wikipedia.org/wiki/Shuttle_Derived_Launch_Vehiclehttp://en.wikipedia.org/wiki/Evolved_Expendable_Launch_Vehiclehttp://en.wikipedia.org/wiki/Crew_Exploration_Vehiclehttp://en.wikipedia.org/wiki/Crew_Exploration_Vehiclehttp://en.wikipedia.org/wiki/Vision_for_Space_Exploration


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Documents

TERM PAPER on Space Craft