Long Duration Exposure Facility
||This article contains orbital elements but does not include an epoch, or date when those elements, which typically vary over time, were correct.|
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|Mission type||Materials research|
|Mission duration||2076 days|
|Distance travelled||1,374,052,506 kilometres (853,796,644 mi)|
|Launch mass||9,700 kilograms (21,400 lb)|
|Start of mission|
|Launch date||April 6, 1984, 13:58:00UTC|
|Rocket||Space Shuttle Challenger
|Launch site||Kennedy LC-39A|
|End of mission|
|Recovered by||Space Shuttle Columbia
|Recovery date||January 12, 1990, 15:16UTC|
|Landing date||January 20, 1990, 09:35:37 UTC|
|Landing site||Edwards Runway 22|
|Perigee||473.0 kilometres (293.9 mi)|
|Apogee||483.0 kilometres (300.1 mi)|
NASA's Long Duration Exposure Facility, or LDEF, was a school bus-sized cylindrical space experiment facility designed to provide long-term data on the space environment and its effects on space systems, materials, spores, and operations.
It successfully carried science and technology experiments for about 5.7 years, that have revealed a broad and detailed collection of space environmental data. The LDEF concept evolved from a spacecraft proposed by NASA Langley Research Center (LaRC) in 1970 to study the meteoroid environment, the Meteoroid and Exposure Module (MEM).
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 on a separate mission retrieve the payload and return it to Earth for analysis. The project was approved in 1974 and LDEF was built at NASA Langley Research Center.
Engineers originally intended that the first mission would about one year, and that several long-duration exposure missions would use the same frame. The exposure facility was actually used for only one 5.7-year mission. 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. A total of 57 experiments were conducted on the LDEF. They investigated the effects on:
- materials, coatings, and thermal systems
- power and spacecraft propulsion
- science (misc experiments)
- electronics and optics
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.
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.
At LDEF's launch, retrieval was scheduled for March 19, 1985, eleven months after deployment. Schedules slipped, postponing the retrieval mission first to 1986, then indefinitely due to the Challenger disaster. It was finally recovered by the Shuttle Columbia on mission STS-32 on January 12, 1990. Columbia approached LDEF in such a way as to minimize possible contamination to LDEF from thruster exhaust. 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.
Columbia landed at Edwards Air Force Base on January 20, 1990. Through the orbiter's rear flight deck windows, LDEF project staff viewed and took photographs of LDEF at Edwards. 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.
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.
- "The Long Duration Exposure Facility". NASA. Langley Research Center. Retrieved 2013-07-29.
- Paul Clancy (Jun 23, 2005). Looking for Life, Searching the Solar System. Cambridge University Press.
- "Space Microbiology". Microbiology and Molecular Biology Reviews 74 (1): 121–156. March 2010. doi: 10.1128/MMBR.00016-09 . Retrieved 2013-07-29.
- "LDEF Archive". Langley Research Center. Retrieved July 16, 2010.
|Wikimedia Commons has media related to Long Duration Exposure Facility.|
- NASA Langley LDEF site
- The Long Duration Exposure Facility (LDEF), Mission 1 Experiments, 1984. NASA SP-473
- Photographic Survey of the LDEF Mission report