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Long Duration Exposure Facility

January 01, 1970

NASA's Long Duration Exposure Facility, or LDEF (pronounced "eldef"), was a cylindrical facility designed to provide long-term experimental data on the outer space environment and its effects on space systems, materials, operations and selected spores' survival.[2][3] It was placed in low Earth orbit by Space Shuttle Challenger in April 1984. The original plan called for the LDEF to be retrieved in March 1985, but after a series of delays it was eventually returned to Earth by Columbia in January 1990.[3]

Long Duration Exposure Facility
LDEF, shortly before deployment, flies on the RMS arm of Space Shuttle Challenger over Baja California.
Mission typeMaterials research
OperatorNASA
COSPAR ID1984-034B
SATCAT no.14898
Websitecrgis.ndc.nasa.gov/historic/Long_Duration_Exposure_Facility_(LDEF)
Mission duration2076 days
Distance travelled1,374,052,506 km (853,796,644 mi)
Orbits completed32,422
Spacecraft properties
ManufacturerLangley
Launch mass9,724 kg (21,438 lb)[1]
Dry mass3,629 kg (8,001 lb)[1]
Start of mission
Launch dateApril 6, 1984, 13:58:00 (1984-04-06UTC13:58Z) UTC
RocketSpace Shuttle Challenger
STS-41-C
Launch siteKennedy LC-39A
End of mission
Recovered bySpace Shuttle Columbia
STS-32
Recovery dateJanuary 12, 1990, 15:16 (1990-01-12UTC15:17Z) UTC
Landing dateJanuary 20, 1990, 09:35:37 UTC
Landing siteEdwards Runway 22
Orbital parameters
Reference systemGeocentric
RegimeLow Earth
Eccentricity7.29E-4
Perigee altitude473.0 km (293.9 mi)
Apogee altitude483.0 km (300.1 mi)
Inclination28.5 degrees
Period94.2 minutes
 

It successfully carried science and technology experiments for about 5.7 years that have revealed a broad and detailed collection of space environmental data. LDEF's 69 months in space provided scientific data on the long-term effects of space exposure on materials, components and systems that has benefited NASA spacecraft designers to this day.[4]

History edit

Researchers identified the potential of the planned Space Shuttle to deliver a payload to space, leave it there for a long-term exposure to the harsh outer space environment, and retrieve it for analysis on a separate mission. The LDEF concept evolved from a spacecraft proposed by NASA's Langley Research Center in 1970 to study the meteoroid environment, the Meteoroid and Exposure Module (MEM).[2] The project was approved in 1974 and LDEF was built at NASA's Langley Research Center.[4]

LDEF was intended to be reused, and redeployed with new experiments, perhaps every 18 months.[5] but after the unintended extension of mission 1 the structure itself was treated as an experiment and intensively studied before being placed into storage.

Launch and deployment edit

The STS-41-C crew of Challenger deployed LDEF on April 7, 1984, into a nearly circular orbit at an altitude of 257 nautical miles.[6]

Design and structure edit

The LDEF structure shape was a 12 sided prism (to fit the shuttle orbiter payload bay), and made entirely from stainless steel. There were 5 or 6 experiments on each of the 12 long sides and a few more on the ends. It was designed to fly with one end facing earth and the other away from earth.[7] Attitude control of LDEF was achieved with gravity-gradient stabilization and inertial distribution to maintain three-axis stability in orbit. Therefore, propulsion or other attitude control systems were not required, making LDEF free of acceleration forces and contaminants from jet firings.[4] There was also a magnetic/viscous damper to stop any initial oscillation after deployment.[7]

It had two grapple fixtures. An FRGF and an active (rigidize sensing) grapple used to send an electronic signal to initiate the 19 experiments that had electrical systems.[7] This activated the Experiment Initiate System (EIS)[8]: 1538  which sent 24 initiation signals to the 20 active experiments. There were six initiation indications which were visible to the deploying astronauts [9]: 109  next to the active grapple fixture.[9]: 111 

Engineers originally intended that the first mission would last about one year, and that several long-duration exposure missions would use the same frame. The exposure facility was actually used for a single 5.7-year mission.

Experiments edit

The LDEF facility was designed to glean information vital to the development of the Space Station Freedom (that was eventually built as the International Space Station) and other spacecraft, especially the reactions of various space building materials to radiation, extreme temperature changes and collisions with space matter.

Some of the experiments had a cover that opened after deployment and was designed to close after about a year,[10] e.g., Space Environment Effects (M0006).[11]

There was no telemetry, but some active experiments recorded data on a magnetic tape recorder that was powered by a lithium sulfur dioxide battery,[10] e.g., the Advanced Photovoltaic Experiment (S0014), which recorded data once a day,[12] the German Solar cell study (S1002),[12]: 91  and the Space Environment Effects on Fiber Optics Systems (M004).[11]: 182 

Six of the seven active experiments that needed to record data used one or two Experiment Power and Data System (EPDS) modules.[8]: 1545  Each EPDS contained a processing and control module, a magnetic tape recorder and two LiSO2 batteries.[8]: 1536  One experiment (S0069) used a 4-track magnetic tape module not as part of an EPDS.[8]: 1540 

Fifty-seven science and technology experiments — involving government and university investigators from the United States, Canada, Denmark, France, Germany, Ireland, the Netherlands, Switzerland, and the United Kingdom — flew on the LDEF mission.[4][3] Interstellar gases also would be trapped in an attempt to find clues into the formation of the Milky Way and the evolution of heavier elements.[4] Some examples are investigation of exposure effects on:

and physics in low gravity – e.g. crystal growth.[13]

At least one of the on-board experiments, the Thermal Control Surfaces Experiment (TCSE), used the RCA 1802 microprocessor.[14]

Experiment results edit

EXOSTACK edit

In the German experiment EXOSTACK, 30% of Bacillus subtilis spores survived the nearly 6 years exposure to outer space when embedded in salt crystals, whereas 80% survived in the presence of glucose, which stabilize the structure of the cellular macromolecules, especially during vacuum-induced dehydration.[15][16]

If shielded against solar UV, spores of B. subtilis were capable of surviving in space for up to 6 years, especially if embedded in clay or meteorite powder (artificial meteorites). The data may support the likelihood of interplanetary transfer of microorganisms within meteorites, the so-called lithopanspermia hypothesis.[16]

SEEDS edit

The Space Exposed Experiment Developed for Students (SEEDS) allowed students the opportunity to grow control and experimental tomato seeds that had been exposed on LDEF comparing and reporting the results. 12.5 million seeds were flown, and students from elementary to graduate school returned 8000 reports to NASA. The L.A. Times misreported that a DNA mutation from space exposure could yield a poisonous fruit. While incorrect, the report served to raise awareness of the experiment and generate discussion.[17] Space seeds germinated sooner and grew faster than the control seeds. Space seeds were more porous than terrestrial seeds.[18]

Retrieval edit

 
LDEF after retrieval.

At LDEF's launch, retrieval was scheduled for March 19, 1985, eleven months after deployment.[4] Schedules slipped, postponing the retrieval mission first to 1986, then indefinitely due to the Challenger disaster. After 5.7 years its orbit had decayed to about 175 nautical miles and it was likely to burn up on reentry in a little over a month.[6][9]: 15 

It was finally recovered by Columbia on mission STS-32 on January 12, 1990.[19] Columbia approached LDEF in such a way as to minimize possible contamination to LDEF from thruster exhaust.[20] While LDEF was still attached to the RMS arm, an extensive 4.5 hour survey photographed each individual experiment tray, as well as larger areas.[20] Nevertheless, shuttle operations did contaminate experiments when concerns for human comfort out-weighed important LDEF mission goals.[21]

Columbia landed at Edwards Air Force Base on January 20, 1990.[4] With LDEF still in its bay, Columbia was ferried back on the Shuttle Carrier Aircraft to the Kennedy Space Center on January 26. Special efforts were taken to ensure protection against contamination of the payload bay during the ferry flight.[4]

Between January 30 and 31, LDEF was removed from Columbia's payload bay in KSC's Orbiter Processing Facility, placed in a special payload canister, and transported to the Operations and Checkout Building. On February 1, 1990, LDEF was transported in the LDEF Assembly and Transportation System to the Spacecraft Assembly and Encapsulation Facility – 2, where the LDEF project team led deintegration activities.[20]

 
Columbia arrives at Kennedy Space Center with LDEF still in its payload bay.
 
LDEF is removed from Columbia's payload bay

See also edit

References edit

  1. ^ a b "Long Duration Exposure Facility (LDEF)". NASA.
  2. ^ a b . NASA. Langley Research Center. Archived from the original on 2013-10-31. Retrieved 2013-07-29.
  3. ^ a b c Allen, Carlton. "Long Duration Exposure Facility (LDEF)". NASA. Retrieved 2014-01-22.
  4. ^ a b c d e f g h i Grinter, Kay (8 January 2010). "Retrieval of LDEF provided resolution, better data" (PDF). Spaceport News. NASA. p. 7. Retrieved 2014-01-22.
  5. ^ LDEF intro
  6. ^ a b
  7. ^ a b c
  8. ^ a b c d LDEF Electronic Systems: Successes, Failures and Lessons, Miller et al. 1991
  9. ^ a b c Dursch, Harry W.; Spear, W. Steve; Miller, Emmett A.; Bohnhoff-Hlavacek, Gail L.; Edelman, Joel (April 1992). Analysis of systems hardware flown on LDEF. Results of the systems special investigation group. NASA Sti/Recon Technical Report N (Report). Vol. 92. p. 31677. Bibcode:1992STIN...9231677D. Retrieved November 11, 2022.
  10. ^ a b
  11. ^ a b Electronics and Optics
  12. ^ a b Advanced Photovoltaic Experiment (S0014)
  13. ^ Growth of Crystals From Solutions in Low Gravity (A0139A)
  14. ^ Wilkes, D. R. (January 1999). "Thermal Control Surfaces Experiment (TCSE)" (PDF). NASA Online Archives. NASA. Retrieved 21 May 2016.
  15. ^ Paul Clancy (Jun 23, 2005). Looking for Life, Searching the Solar System. Cambridge University Press.
  16. ^ a b Horneck, Gerda; David M. Klaus; Rocco L. Mancinelli (March 2010). "Space Microbiology". Microbiology and Molecular Biology Reviews. 74 (1): 121–156. Bibcode:2010MMBR...74..121H. doi:10.1128/mmbr.00016-09. PMC 2832349. PMID 20197502.
  17. ^ Sindelar, Terri (April 17, 1992). "Attack of the Killer Space Tomatoes? Not!". Washington, D.C.: NASA.
  18. ^ Hammond EC, Bridgers K, Berry FD (1996). "Germination, growth rates, and electron microscope analysis of tomato seeds flown on the LDEF". Radiat Meas. 26 (6): 851–61. Bibcode:1996RadM...26..851H. doi:10.1016/S1350-4487(96)00093-5. hdl:2060/19950017401. PMID 11540518. S2CID 42665560.
  19. ^ . Langley Research Center. Archived from the original on October 31, 2013. Retrieved July 16, 2010.
  20. ^ a b c Kramer, Herbert J. "LDEF (Long Duration Exposure Facility)". NASA. Earth Observation Portal. Retrieved 2014-01-22.
  21. ^ Zolensky, M. "Lessons Learned from Three Recent Sample Return Missions" (PDF).

External links edit

 
Wikimedia Commons has media related to Long Duration Exposure Facility.
  • . Archived from the original on May 29, 2016. Retrieved September 11, 2016.
  • NASA Johnson Space Center LDEF site
    • LDEF Intercostal Data and Plots re micrometeoroids cratering
    • LDEF Map of Experiment Locations
  • The Long Duration Exposure Facility (LDEF), Mission 1 Experiments, 1984. NASA SP-473

January 01, 1970
long, duration, exposure, facility, nasa, ldef, pronounced, eldef, cylindrical, facility, designed, provide, long, term, experimental, data, outer, space, environment, effects, space, systems, materials, operations, selected, spores, survival, placed, earth, o. NASA s Long Duration Exposure Facility or LDEF pronounced eldef was a cylindrical facility designed to provide long term experimental data on the outer space environment and its effects on space systems materials operations and selected spores survival 2 3 It was placed in low Earth orbit by Space Shuttle Challenger in April 1984 The original plan called for the LDEF to be retrieved in March 1985 but after a series of delays it was eventually returned to Earth by Columbia in January 1990 3 Long Duration Exposure FacilityLDEF shortly before deployment flies on the RMS arm of Space Shuttle Challenger over Baja California Mission typeMaterials researchOperatorNASACOSPAR ID1984 034BSATCAT no 14898Websitecrgis wbr ndc wbr nasa wbr gov wbr historic wbr Long wbr Duration wbr Exposure wbr Facility wbr LDEF Mission duration2076 daysDistance travelled1 374 052 506 km 853 796 644 mi Orbits completed32 422Spacecraft propertiesManufacturerLangleyLaunch mass9 724 kg 21 438 lb 1 Dry mass3 629 kg 8 001 lb 1 Start of missionLaunch dateApril 6 1984 13 58 00 1984 04 06UTC13 58Z UTCRocketSpace Shuttle ChallengerSTS 41 CLaunch siteKennedy LC 39AEnd of missionRecovered bySpace Shuttle ColumbiaSTS 32Recovery dateJanuary 12 1990 15 16 1990 01 12UTC15 17Z UTCLanding dateJanuary 20 1990 09 35 37 UTCLanding siteEdwards Runway 22Orbital parametersReference systemGeocentricRegimeLow EarthEccentricity7 29E 4Perigee altitude473 0 km 293 9 mi Apogee altitude483 0 km 300 1 mi Inclination28 5 degreesPeriod94 2 minutes It successfully carried science and technology experiments for about 5 7 years that have revealed a broad and detailed collection of space environmental data LDEF s 69 months in space provided scientific data on the long term effects of space exposure on materials components and systems that has benefited NASA spacecraft designers to this day 4 Contents 1 History 2 Launch and deployment 3 Design and structure 4 Experiments 5 Experiment results 5 1 EXOSTACK 5 2 SEEDS 6 Retrieval 7 See also 8 References 9 External linksHistory editResearchers identified the potential of the planned Space Shuttle to deliver a payload to space leave it there for a long term exposure to the harsh outer space environment and retrieve it for analysis on a separate mission The LDEF concept evolved from a spacecraft proposed by NASA s Langley Research Center in 1970 to study the meteoroid environment the Meteoroid and Exposure Module MEM 2 The project was approved in 1974 and LDEF was built at NASA s Langley Research Center 4 LDEF was intended to be reused and redeployed with new experiments perhaps every 18 months 5 but after the unintended extension of mission 1 the structure itself was treated as an experiment and intensively studied before being placed into storage Launch and deployment editThe STS 41 C crew of Challenger deployed LDEF on April 7 1984 into a nearly circular orbit at an altitude of 257 nautical miles 6 Design and structure editThe LDEF structure shape was a 12 sided prism to fit the shuttle orbiter payload bay and made entirely from stainless steel There were 5 or 6 experiments on each of the 12 long sides and a few more on the ends It was designed to fly with one end facing earth and the other away from earth 7 Attitude control of LDEF was achieved with gravity gradient stabilization and inertial distribution to maintain three axis stability in orbit Therefore propulsion or other attitude control systems were not required making LDEF free of acceleration forces and contaminants from jet firings 4 There was also a magnetic viscous damper to stop any initial oscillation after deployment 7 It had two grapple fixtures An FRGF and an active rigidize sensing grapple used to send an electronic signal to initiate the 19 experiments that had electrical systems 7 This activated the Experiment Initiate System EIS 8 1538 which sent 24 initiation signals to the 20 active experiments There were six initiation indications which were visible to the deploying astronauts 9 109 next to the active grapple fixture 9 111 Engineers originally intended that the first mission would last about one year and that several long duration exposure missions would use the same frame The exposure facility was actually used for a single 5 7 year mission Experiments editThe LDEF facility was designed to glean information vital to the development of the Space Station Freedom that was eventually built as the International Space Station and other spacecraft especially the reactions of various space building materials to radiation extreme temperature changes and collisions with space matter Some of the experiments had a cover that opened after deployment and was designed to close after about a year 10 e g Space Environment Effects M0006 11 There was no telemetry but some active experiments recorded data on a magnetic tape recorder that was powered by a lithium sulfur dioxide battery 10 e g the Advanced Photovoltaic Experiment S0014 which recorded data once a day 12 the German Solar cell study S1002 12 91 and the Space Environment Effects on Fiber Optics Systems M004 11 182 Six of the seven active experiments that needed to record data used one or two Experiment Power and Data System EPDS modules 8 1545 Each EPDS contained a processing and control module a magnetic tape recorder and two LiSO2 batteries 8 1536 One experiment S0069 used a 4 track magnetic tape module not as part of an EPDS 8 1540 Fifty seven science and technology experiments involving government and university investigators from the United States Canada Denmark France Germany Ireland the Netherlands Switzerland and the United Kingdom flew on the LDEF mission 4 3 Interstellar gases also would be trapped in an attempt to find clues into the formation of the Milky Way and the evolution of heavier elements 4 Some examples are investigation of exposure effects on materials coatings and thermal systems power and spacecraft propulsion optical fibers and pure crystals for use in electronics electronics and optics survival of tomato seeds and bacterial spores 4 and physics in low gravity e g crystal growth 13 At least one of the on board experiments the Thermal Control Surfaces Experiment TCSE used the RCA 1802 microprocessor 14 Experiment results editEXOSTACK edit In the German experiment EXOSTACK 30 of Bacillus subtilis spores survived the nearly 6 years exposure to outer space when embedded in salt crystals whereas 80 survived in the presence of glucose which stabilize the structure of the cellular macromolecules especially during vacuum induced dehydration 15 16 If shielded against solar UV spores of B subtilis were capable of surviving in space for up to 6 years especially if embedded in clay or meteorite powder artificial meteorites The data may support the likelihood of interplanetary transfer of microorganisms within meteorites the so called lithopanspermia hypothesis 16 SEEDS edit The Space Exposed Experiment Developed for Students SEEDS allowed students the opportunity to grow control and experimental tomato seeds that had been exposed on LDEF comparing and reporting the results 12 5 million seeds were flown and students from elementary to graduate school returned 8000 reports to NASA The L A Times misreported that a DNA mutation from space exposure could yield a poisonous fruit While incorrect the report served to raise awareness of the experiment and generate discussion 17 Space seeds germinated sooner and grew faster than the control seeds Space seeds were more porous than terrestrial seeds 18 Retrieval edit nbsp LDEF after retrieval At LDEF s launch retrieval was scheduled for March 19 1985 eleven months after deployment 4 Schedules slipped postponing the retrieval mission first to 1986 then indefinitely due to the Challenger disaster After 5 7 years its orbit had decayed to about 175 nautical miles and it was likely to burn up on reentry in a little over a month 6 9 15 It was finally recovered by Columbia on mission STS 32 on January 12 1990 19 Columbia approached LDEF in such a way as to minimize possible contamination to LDEF from thruster exhaust 20 While LDEF was still attached to the RMS arm an extensive 4 5 hour survey photographed each individual experiment tray as well as larger areas 20 Nevertheless shuttle operations did contaminate experiments when concerns for human comfort out weighed important LDEF mission goals 21 Columbia landed at Edwards Air Force Base on January 20 1990 4 With LDEF still in its bay Columbia was ferried back on the Shuttle Carrier Aircraft to the Kennedy Space Center on January 26 Special efforts were taken to ensure protection against contamination of the payload bay during the ferry flight 4 Between January 30 and 31 LDEF was removed from Columbia s payload bay in KSC s Orbiter Processing Facility placed in a special payload canister and transported to the Operations and Checkout Building On February 1 1990 LDEF was transported in the LDEF Assembly and Transportation System to the Spacecraft Assembly and Encapsulation Facility 2 where the LDEF project team led deintegration activities 20 nbsp Columbia arrives at Kennedy Space Center with LDEF still in its payload bay nbsp LDEF is removed from Columbia s payload baySee also edit nbsp Spaceflight portal European Retrievable Carrier 1992 1993 Space Flyer Unit 1995 1996 Mir Environmental Effects Payload 1996 1997 Materials International Space Station Experiment 1 8 from 2001References edit a b Long Duration Exposure Facility LDEF NASA a b The Long Duration Exposure Facility NASA Langley Research Center Archived from the original on 2013 10 31 Retrieved 2013 07 29 a b c Allen Carlton Long Duration Exposure Facility LDEF NASA Retrieved 2014 01 22 a b c d e f g h i Grinter Kay 8 January 2010 Retrieval of LDEF provided resolution better data PDF Spaceport News NASA p 7 Retrieved 2014 01 22 LDEF intro a b archive of larc LDEF a b c LDEF structure a b c d LDEF Electronic Systems Successes Failures and Lessons Miller et al 1991 a b c Dursch Harry W Spear W Steve Miller Emmett A Bohnhoff Hlavacek Gail L Edelman Joel April 1992 Analysis of systems hardware flown on LDEF Results of the systems special investigation group NASA Sti Recon Technical Report N Report Vol 92 p 31677 Bibcode 1992STIN 9231677D Retrieved November 11 2022 a b LDEF Trays and Experiments a b Electronics and Optics a b Advanced Photovoltaic Experiment S0014 Growth of Crystals From Solutions in Low Gravity A0139A Wilkes D R January 1999 Thermal Control Surfaces Experiment TCSE PDF NASA Online Archives NASA Retrieved 21 May 2016 Paul Clancy Jun 23 2005 Looking for Life Searching the Solar System Cambridge University Press a b Horneck Gerda David M Klaus Rocco L Mancinelli March 2010 Space Microbiology Microbiology and Molecular Biology Reviews 74 1 121 156 Bibcode 2010MMBR 74 121H doi 10 1128 mmbr 00016 09 PMC 2832349 PMID 20197502 Sindelar Terri April 17 1992 Attack of the Killer Space Tomatoes Not Washington D C NASA Hammond EC Bridgers K Berry FD 1996 Germination growth rates and electron microscope analysis of tomato seeds flown on the LDEF Radiat Meas 26 6 851 61 Bibcode 1996RadM 26 851H doi 10 1016 S1350 4487 96 00093 5 hdl 2060 19950017401 PMID 11540518 S2CID 42665560 LDEF Archive Langley Research Center Archived from the original on October 31 2013 Retrieved July 16 2010 a b c Kramer Herbert J LDEF Long Duration Exposure Facility NASA Earth Observation Portal Retrieved 2014 01 22 Zolensky M Lessons Learned from Three Recent Sample Return Missions PDF External links edit nbsp Wikimedia Commons has media related to Long Duration Exposure Facility NASA Langley LDEF Site Archived from the original on May 29 2016 Retrieved September 11 2016 NASA Johnson Space Center LDEF site LDEF Intercostal Data and Plots re micrometeoroids cratering LDEF Map of Experiment Locations The Long Duration Exposure Facility LDEF Mission 1 Experiments 1984 NASA SP 473 Retrieved from https en 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