national space transportation system overview

8/8/2019 National Space Transportation System Overview

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CONTENTS

SPACE SHUTTLE PROGRAM ......................................... 1SPACE SHUTTLE REQUIREMENTS ................................... 1LAUNCH SITES .................................................... 3BACKGROUND AND STATUS ........................................ 5MISSION PROFILE ................................................. 8Aborts ........................................................ 10

Return to Launch Site ............................................ 11Transatlantic Landing Abort ........................................ 12Abort to Orbit .................................................. 12Abort Once Around ............................................. 13Contingency Abort .............................................. 13ORBITER GROUND TURNAROUND .................................. 13

OPERATIONAL IMPROVEMENTS AND MODIFICATIONS ................ 18Orbiter ........................................................ 18

OMS and RCS System AC-motor-operated valves ......................... 18Primary Reaction Control System Thrusters .............................. 18Fuel Cell Power Plants ............................................ 18Auxiliary Power Units ............................................. 18Main Landing Gear .............................................. 19Nose Wheel Steering ............................................. 19Thermal Protection System ......................................... 20Wing Modification .............................................. 20Mid-Fuselage Modifications ........................................ 20General Purpose Computers ........................................ 20Inertial Measurement Units ......................................... 20Crew Escape System ............................................. 21Emergency Egress Slide ........................................... 2117-inch Orbiter/Extemal Tank Disconnects .............................. 21

Space Shuttle Main Engine Margin Improvement Program ............... 22SSME Hight Program ............................................ 22

Solid Rocket Motor Redesign ...................................... 23Original versus Redesigned SRM Field Joint ............................ 23Original versus Redesigned SRM Case-to-Nozzle Joint ..................... 23Nozzle ...................................................... 23Factory Joint ................................................. 26Propellant .................................................... 2 6Ignition System ................................................. 26Ground Support Equipment ........................................ 26Design Analysis Summary ......................................... 26Veilfication/Certification Test ....................................... 26Non-Destructive Evaluation ........................................ 26Contingency Planning ............................................ 29Independent Oversight ............................................ 29NSTS PROGRAM MANAGEMENT .................................... 29

NSTS Organization .............................................. 30Launch Constraing Procedures ..................................... 31Launch Decision Process ......................................... 31Management Communications ...................................... 32

CHRONOLOGY .................................................... 33

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SPACETRANSPORTATIONSYSTEMSPACESHUTTLE PROGRAM

The Space Shuttle is developed by theNational Aeronautics and Space Administration.NASA coordinates and manages the SpaceTransportation System (NASA's name for theoverall Shuttle program), includingintergovernmental agency requirements andinternational and joint projects. NASA alsooversees the launch and space flight requirementsfor civilian and commercial use.

The Space Shuttle system consists of fourprimary elements: an orbiter spacecraft, two SolidRocket Boosters (SRB), an external tank to housefuel and oxidizer and three Space Shuttle mainengines.The orbiter is built by Rockwell Intemational 's

Space Transportation Systems Division, Downey,Calif., which also has responsibility for theintegration of the overall space transportationsystem. Both orbiter and integration contracts areunder the direction of NASA's Johnson SpaceCenter in Houston, Texas.

The SRB motors are built by the WasatchDivision of Morton Thiokol Corp., Brigham City,Utah, and are assembled, checked out andrefurbished by United Space Boosters Inc.,Booster Production Co., Kennedy Space Center,Cape Canaveral, Fla. The external tank is built byMartin Marietta Corp. at its Michoud facility, NewOrleans, La., and the Space Shuttle main enginesare built by Rockwell's Rocketdyne Division,Canoga Park, Calif. These contracts are under thedirection of NASA's George C. Marshall SpaceFlight Center, Huntsville, Ala.

SPACE SHUTTLE REQUIREMENTSThe Shuttle will transport cargo into near Earth

orbit 100 to 217 nautical miles (115 to 250 statutemiles) above the Earth. This cargo -- or payload --is carried in a bay 15 feet in diameter and 60 ftlong.

Major system requirements are that the orbiterand the two solid rocket boosters b_ reusable.

Other features of the Shuttle:The orbiter has carried a flight crew of up to

eight persons. A total of 10 persons could becarried under emergency conditions The basicmission is 7 days in space. The crew compartmenthas a shirtsleeve environment, and the accelerationload is never greater than 3 Gs. In its return toEarth, the orbiter has a cross-range maneuveringcapability of 1,100 nautical miles (1,265 statutemiles).

The Space Shuttle is launched in an uprightposition, with thrust provided by the three SpaceShuttle engines and the two SRB. After about 2minutes, the two boosters are spent and areseparated from the extemal tank. They fall into theocean at predetermined points and are recoveredfor reuse.

LengthHeightWingspanApproximateweight* Grossift-off,whichwigvarydependingonpayloadweightandonboardconsumables

Nominalend-of-missionlandingwithpayload,whichwiflvarydependingonpayloadreturnweight

Thrust(sealevel} Solidrocketboosters Orbitermainengines

Cargobay Length Diameter

Overall Shuttle Orbiter184.2 feet76.6 feet

4.5 millionpounds

3,300,000 poundsofthrusteachinvacuum

122.17 feet56.67 feet78.06 feet

230,000 pounds

393,800 poundsof thrusteachat sealevldat104 percent60 feet15 feet

Space Shuttle ProgramThe Space Shuttle main engines continue

firing for about 8 minutes. They shut down justbefore the craft is inserted into orbit. The externaltank is then separated from the orbiter. It followsa ballistic trajectory into a remote area of the oceanbut is not recovered.

There are 38 primary Reaction Control System(RCS) engines and six vemier RCS engineslocated on the orbiter. The first use of selectedprimary reaction control system engines occurs atorbiter/external tank separation. The selected

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primaryreactioncontrolsystemenginesareusedin theseparationsequenceoprovideanattitudeholdfor separation.Thentheymovetheorbiterawayfrom theexternaltank to ensureorbiterclearanceromtheareof therotatingexternalank.Finally,theyreturnto anattitudeholdpriorto theinitiationof thefiringof theOrbitalManeuveringSystem(OMS)engineso placetheorbiterintoorbit.Theprimaryand/orvemierRCSenginesareusednormallyonorbit to provide attitude pitch,

roll and yaw maneuvers as well as translationmaneuvers.

orbit, and only one thrusting sequence is used fordeorbit.The orbiter's velocity on orbit is

approximately 25,405 feet per second (17,322statute miles per hour). The deorbit maneuverdecreases this velocity approximately 300 fps(205 mph) for reentry.

In some missions, only one OMS thrustingsequence is used to place the orbiter on orbit. Thisis referred to as direct insertion. Direct insertion isa technique used in some missions where there arehigh-performance requirements, such as a heavy

SolidRocketBooster12.17 FeetDiameter

ExternalTank _ _ |

:: '-++-'-- " I122.17 Feet - [

Orbiter Tank-OrbiterAttachments

76.6 Feet

149.16 Feet154.2 Feet

184.2 Feet

Space Shuttle Statistics

OrbiterWeightinPoundsApproximate}OrbiterVehicle TotalDryWeightWith TotalDryWeight(OV} ThreeSpaceShuttle WithoutThreeSpecs

MainEngines ShuttleMainEnginesOV-102 Columbia 178,289 157,289OV-103 Discovery 171,419 151,419OV-104Atlantis 171,205 151,205

SolidRocketBoosterWeightsnPounds(Approximate)1,300,000, EachatLaunchPropellantWeight1,100,000, Each).InertWeight192,000, Each.

ExternalTankWeightinPoundsApproximate)1,655,600 WithPropellants.nertWeight66,000.

56.8!

ool_ _!

The two OMS engines are used to place theorbiter on orbit, for major velocity maneuvers onorbit and to slow the orbiter for reentry, called thedeorbit maneuver. Normally, two OMS enginethrusting sequences are used to place the orbiter on

payload or a high orbital altitude. This techniqueuses the Space Shuttle main engines to achieve thedesired apogee (high point in an orbit) altitude,thus conserving orbital maneuvering systempropellants. Following jettison of the external

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tank, only one OMS thrusting sequence is requiredto establish the desired orbit altitude.For deorbit, the orbiter is rotated tail first in

the direction of the velocity by the primary reactioncontrol system engines. Then the OMS enginesare used to decrease the orbiter's velocity.

During the initial entry sequence, selectedprimary RCS engines are used to control theorbiter's attitude (pitch, roll and yaw). Asaerodynamic pressure builds up, the orbiter flightcontrol surfaces become active and the primaryreaction control system engines are inhibited.

During entry, the thermal protection systemcovering the entire orbiter provides the protectionfor the orbiter to survive the extremely hightemperatures encountered during entry. Thethermal protection system is reusable (it does notbum offor ablate during entry).

The unpowered orbiter glides to Earth andlands on a runway like an airplane. Nominaltouchdown speed varies from 184 to 196 knots(213 to 225 miles per hour).

The main landing gear wheels have a brakingsystem for stopping the orbiter on the runway, andthe nose wheel is steerable, again similar to aconventional airplane.

There are two launch sites for the SpaceShuttle. Kennedy Space Center (KSC) in Floridais used for launches to place the orbiter inequatorial orbits (around the equator), andVandenberg Air Force Base launch site inCalifornia will be used for launches that place fileorbiter in polar orbit missions.

Landing sites are located at the KSC andVandenberg. Additional landing sites are providedat Edwards Air Force Base in California and WhiteSands, N.M. Contingency landing sites are alsoprovided in the event the orbiter must return toEarth in an emergency.LAUNCH SITES

Space Shuttles destined for equatorial orbitsare launched from the KSC, and those requiringpolar orbital planes will be launched fromVandenberg.

Orbital mechanics and the complexities ofmission requirements, plus safety and thepossibility of infringement on foreign air and landspace, prohibit polar orbit launches from the KSC.

Kennedy Space Center launches have anallowable path no less than 35 degrees northeastand no greater than 120 degrees southeast. Theseare azimuth degree readings based on due eastfrom KSC as 90 degrees.

A 35-degree azimuth launch places thespacecraft in an orbital inclination of 57 degrees.This means the spacecraft in its orbital trajectoriesaround the Earth will never exceed an Earthlatitude higher or lower than 57 degrees north orsouth of the equator.

A launch path from KSC at an azimuth of 120degrees will place the spacecraft in an orbitalinclination of 39 degrees (it will be above or below39 degrees north or south of the equator).

national space transportation system overview

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