sts aborts. abort types there are two classifications of aborts available to the crews during the...

STS AbortsSTS Aborts


Abort TypesAbort Types

There are two classifications of aborts available to the crews There are two classifications of aborts available to the crews during the launch phase of the Space Shuttle mission. The first during the launch phase of the Space Shuttle mission. The first is the intact abort which enlist various procedures to return the is the intact abort which enlist various procedures to return the vehicle for a landing at the launch or alternate sites. The vehicle for a landing at the launch or alternate sites. The second is the contingency abort that is used for crew survival second is the contingency abort that is used for crew survival in a controlled glide by abandoning the vehicle with a crew-in a controlled glide by abandoning the vehicle with a crew-parachute landing.parachute landing.

Intact abortsIntact abortsThe intact aborts include from most desirable to least The intact aborts include from most desirable to least desirable:desirable:

Abort To Orbit (ATO) Abort To Orbit (ATO) Abort Once Around (AOA) Abort Once Around (AOA) Trans Atlantic Landing (TAL) Trans Atlantic Landing (TAL) Return To Launch Site (RTLS) Return To Launch Site (RTLS)


Abort TypesAbort Types

Contingency abortContingency abort

A contingency abort used for crew survival in more A contingency abort used for crew survival in more serious flight conditions caused by the loss of more serious flight conditions caused by the loss of more than one SSME, or failures in other systems that do than one SSME, or failures in other systems that do not allow a landing or RTLS abort. Most three not allow a landing or RTLS abort. Most three engine-out ascent scenarios necessitates this abort engine-out ascent scenarios necessitates this abort mode in which case the orbiter would have to be mode in which case the orbiter would have to be ditched, although a contingency abort is never ditched, although a contingency abort is never chosen if another abort option exists. The in-flight chosen if another abort option exists. The in-flight crew escape system would be used before ditching crew escape system would be used before ditching the Orbiter. the Orbiter.


Decision on abort modesDecision on abort modes

The decision on when to abort a mission and The decision on when to abort a mission and which abort mode to execute is based which abort mode to execute is based generally on the highest preferred type of generally on the highest preferred type of abort that is allowed by the remaining abort that is allowed by the remaining performance of STS/Orbiterperformance of STS/Orbiter

Timing for the abort is dependent on the Timing for the abort is dependent on the severity of the system/engine failure as is the severity of the system/engine failure as is the abort mode which makes the decision abort mode which makes the decision process a complex procedure of determining process a complex procedure of determining the cause and timing of the failure causing the cause and timing of the failure causing the abort quicklythe abort quickly


Decision on abort modesDecision on abort modes

If communications exists between the Orbiter If communications exists between the Orbiter crew and NASA's Mission Control Center-crew and NASA's Mission Control Center-HoustonHouston Calling the abort is the responsibility of the Calling the abort is the responsibility of the

Mission Control Center since it has more Mission Control Center since it has more complete knowledge of the Orbiter and its complete knowledge of the Orbiter and its position than the crewposition than the crew

If communications are lostIf communications are lost Crew has onboard information and Crew has onboard information and

equipment to allow them to determine the equipment to allow them to determine the optimum abort procedureoptimum abort procedure

STS Aborts - ATOSTS Aborts - ATO

IIntact Abortsntact Aborts

Abort To Orbit (ATO)Abort To Orbit (ATO)

An ATO is an abort mode that allows the Orbiter to An ATO is an abort mode that allows the Orbiter to achieve a lower orbital altitude when performance achieve a lower orbital altitude when performance has been losthas been lost

Temporary lower orbit can be used for transferring to Temporary lower orbit can be used for transferring to the planned orbit if possible, or to execute a the planned orbit if possible, or to execute a modified deorbit for a for landingmodified deorbit for a for landing Most preferable abort modeMost preferable abort mode


IIntact Abortsntact Aborts

Abort To Orbit (ATO)Abort To Orbit (ATO)

Only one abort executed in the STS programOnly one abort executed in the STS program Challenger flight launched on 29 July 1985 Challenger flight launched on 29 July 1985

5 min 45 sec into ascent a sensor problem caused 5 min 45 sec into ascent a sensor problem caused center engine #1 to shutdown prematurelycenter engine #1 to shutdown prematurely

Loss of thrust precluded Challenger from Loss of thrust precluded Challenger from achieving its 190 nm orbitachieving its 190 nm orbit

Instead placed in a 140 nm orbit as part of the Instead placed in a 140 nm orbit as part of the ATO procedureATO procedure

Lower orbit had little impact on the missionLower orbit had little impact on the mission Crew and Orbiter met objectives successfullyCrew and Orbiter met objectives successfully

STS Aborts - AOASTS Aborts - AOA

Intact AbortsIntact Aborts

Orbit Once-Around (AOA) Orbit Once-Around (AOA)

The Abort Once Around allows the vehicle to complete The Abort Once Around allows the vehicle to complete one orbit to setup normal entry and landing where one orbit to setup normal entry and landing where reduced Orbiter performance or reduced fuel does reduced Orbiter performance or reduced fuel does not allow entry to the planned orbitnot allow entry to the planned orbit

AOA uses two OMS burnsAOA uses two OMS burns

Second most preferable abort modeSecond most preferable abort mode

Approximately 90 minute return time Approximately 90 minute return time

Landing sites for the AOA are at KSC, White Sands NM, or Landing sites for the AOA are at KSC, White Sands NM, or Edwards AFBEdwards AFB

STS Aborts - AOASTS Aborts - AOA

STS Aborts - TALSTS Aborts - TAL


Transoceanic Abort Landing (TAL)Transoceanic Abort Landing (TAL)

The Transoceanic Abort Landing is employed for an The Transoceanic Abort Landing is employed for an engine failure beyond the RTLS limit but before engine failure beyond the RTLS limit but before reaching the Abort Once Around point.reaching the Abort Once Around point.

Suborbital TAL procedure includes one or more Suborbital TAL procedure includes one or more preselected landing sites on the European and preselected landing sites on the European and African continents based on the orbital inclinationAfrican continents based on the orbital inclination



Transoceanic Abort Landing (TAL)Transoceanic Abort Landing (TAL)

Does not need an OMS burn, but does require a Does not need an OMS burn, but does require a OMS/RCS propellant dump in flightOMS/RCS propellant dump in flight

TAL is the third most preferable abortTAL is the third most preferable abort

Landing site based on flight track (inclination) Landing site based on flight track (inclination) Moron, Spain (MRN)Moron, Spain (MRN) Dakar, Senegal (ZZA)Dakar, Senegal (ZZA) Ben Guerur, Morocco (BEN)Ben Guerur, Morocco (BEN)

STS Aborts - RTLSSTS Aborts - RTLS


Return To Launch Site (RTLS)Return To Launch Site (RTLS)

The RTLS is the most complex and least preferable The RTLS is the most complex and least preferable intact abort intact abort

Part of the post-failure flight can be under SRB thrust, Part of the post-failure flight can be under SRB thrust, and following separation, under SSME power for a and following separation, under SSME power for a return to the landing sitereturn to the landing site Part of which is in retrograde (reverse) flight under SSME Part of which is in retrograde (reverse) flight under SSME

powerpower




Used For loss of single SSME between liftoff Used For loss of single SSME between liftoff and 420s where not enough fuel remains for and 420s where not enough fuel remains for return and for three-engine returnreturn and for three-engine return Executed between liftoff and 3m 34s Executed between liftoff and 3m 34s

Approximately 24 minute return time Approximately 24 minute return time




The RTLS is divided into three stages The RTLS is divided into three stages

1. Powered stage - SSME and SRB still operating 1. Powered stage - SSME and SRB still operating Flight must continue until SRB separation to avoid Flight must continue until SRB separation to avoid

catastrophic structural failure catastrophic structural failure Flight is continued downrange to burn enough fuel to allow Flight is continued downrange to burn enough fuel to allow

turn, then return to KSC landing strip turn, then return to KSC landing strip Turn is executed during powered thrust (thrust reverse to Turn is executed during powered thrust (thrust reverse to

flight during last part of turn) flight during last part of turn)




2. ET separation2. ET separation RCS used to separate Orbiter from ET RCS used to separate Orbiter from ET

3. Glide phase3. Glide phase Normal gliding approach to landingNormal gliding approach to landing

STS Aborts - ContingencySTS Aborts - Contingency

Contingency AbortContingency Abort

Contingency aborts are caused by loss of more than Contingency aborts are caused by loss of more than one main engine or failures in other critical systemsone main engine or failures in other critical systems

Such an abort would maintain orbiter integrity for in-Such an abort would maintain orbiter integrity for in-flight crew escape if a landing cannot be made at a flight crew escape if a landing cannot be made at a suitable landing sitesuitable landing site

Contingency aborts due to system failures other than Contingency aborts due to system failures other than those involving the main engines would normally those involving the main engines would normally result in an intact recovery of vehicle and crewresult in an intact recovery of vehicle and crew

STS Aborts - ContingencySTS Aborts - Contingency

Contingency AbortContingency Abort

Loss of more than one main engine could result Loss of more than one main engine could result in a safe runway landingin a safe runway landing

In most three-engine-out cases during ascent, In most three-engine-out cases during ascent, the orbiter would have to be ditchedthe orbiter would have to be ditched

The in-flight crew escape system would be used The in-flight crew escape system would be used before ditching the Orbiterbefore ditching the Orbiter

Altitude range for bailout approximately 20,000’ to Altitude range for bailout approximately 20,000’ to 10,000’10,000’

STS Aborts – ContingencySTS Aborts – Contingency

STS Landing SitesSTS Landing Sites

End-of-Mission SitesEnd-of-Mission Sites

Kennedy Space Center, Florida Kennedy Space Center, Florida

Edwards Air Force Base, California Edwards Air Force Base, California

White Sands Space Harbor, New MexicoWhite Sands Space Harbor, New Mexico

STS Landing Sites U.S. & CanadaSTS Landing Sites U.S. & Canada

STS Augmented Landing SitesSTS Augmented Landing Sites

Istres Air Base, France Istres Air Base, France

Moron Air Base, Spain Moron Air Base, Spain

Zaragoza Air Base, Spain (high inclination orbit only) Zaragoza Air Base, Spain (high inclination orbit only)

Yundum Airport, Banjul, The Gambia (low inclination Yundum Airport, Banjul, The Gambia (low inclination orbit only) orbit only)

Base Aerienne, Ben Guerir, MoroccoBase Aerienne, Ben Guerir, Morocco

Dakar, SenegalDakar, Senegal

STS Augmented Landing Sites - AtlanticSTS Augmented Landing Sites - Atlantic

STS Emergency Landing SitesSTS Emergency Landing Sites

Dyess Air Force Base, Texas Dyess Air Force Base, Texas Ellsworth Air Force Base, South Dakota Ellsworth Air Force Base, South Dakota Grant County (Moses Lake), Washington Grant County (Moses Lake), Washington Lincoln Municipal Airport, Nebraska Lincoln Municipal Airport, Nebraska Mountain Home Air Force Base, Idaho Mountain Home Air Force Base, Idaho Orlando International Airport, Florida Orlando International Airport, Florida Tamanrassett, Algeria Tamanrassett, Algeria Amberley, Australia Amberley, Australia Darwin, Australia Darwin, Australia Lajes Air Base, Azores (mid inclination orbit only) Lajes Air Base, Azores (mid inclination orbit only) Nassau, Bahamas Nassau, Bahamas Gran Canaria (Las Palmas), Canary Islands Gran Canaria (Las Palmas), Canary Islands Amilcar Cabral, Cape Verde Amilcar Cabral, Cape Verde Naval Support Activity Souda Bay, Crete (mid inclination orbit only) Naval Support Activity Souda Bay, Crete (mid inclination orbit only) Navy Support Facility Diego Garcia, Chagos Island Navy Support Facility Diego Garcia, Chagos Island Koln-Bonn, Germany Koln-Bonn, Germany Roberts International Airport (Monrovia), Liberia Roberts International Airport (Monrovia), Liberia King Khalid International Airport, Saudi Arabia King Khalid International Airport, Saudi Arabia Hoedspruit, South Africa Hoedspruit, South Africa Arlanda, Sweden Arlanda, Sweden Esenboga, Turkey Esenboga, Turkey Royal Air Force Base Fairford, United Kingdom (high inclination orbit only) Royal Air Force Base Fairford, United Kingdom (high inclination orbit only) Kinshasa, Zaire Kinshasa, Zaire Shannon, IrelandShannon, Ireland Beja, PortugalBeja, Portugal

STS Launch Abort SitesSTS Launch Abort Sites

Myrtle Beach, South Carolina (high inclination orbit only) Myrtle Beach, South Carolina (high inclination orbit only) Marine Corps Air Station Cherry Point, North Carolina (high Marine Corps Air Station Cherry Point, North Carolina (high

inclination orbit only) inclination orbit only) Naval Air Station Oceana, Virginia Beach, Virginia (high Naval Air Station Oceana, Virginia Beach, Virginia (high

inclination orbit only) inclination orbit only) Dover Air Force Base, Delaware (high inclination orbit only) Dover Air Force Base, Delaware (high inclination orbit only) Otis Air National Guard Base, Massachusetts (high inclination Otis Air National Guard Base, Massachusetts (high inclination

orbit only) orbit only) Pease Air National Guard Base, New Hampshire (high Pease Air National Guard Base, New Hampshire (high

inclination orbit only) inclination orbit only) Naval Air Station Bermuda (low or mid inclination orbit only) Naval Air Station Bermuda (low or mid inclination orbit only) Gander, Newfoundland, CanadaGander, Newfoundland, Canada Goose Bay, Newfoundland, CanadaGoose Bay, Newfoundland, Canada Halifax International Airport, Nova Scotia, CanadaHalifax International Airport, Nova Scotia, Canada St. John's, Newfoundland, CanadaSt. John's, Newfoundland, Canada Stephenville, Newfoundland, CanadaStephenville, Newfoundland, Canada

FinisFinis

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