NASA materials science satellite
Long Duration Exposure Facility
|
|
Mission type
| Materials research
|
---|
Operator
| NASA
|
---|
COSPAR ID
| 1984-034B
|
---|
SATCAT
no.
| 14898
|
---|
Website
| crgis
.ndc
.nasa
.gov
/historic
/Long
_Duration
_Exposure
_Facility
_(LDEF)
|
---|
Mission duration
| 2076 days
|
---|
Distance travelled
| 1,374,052,506 km (853,796,644 mi)
|
---|
Orbits completed
| 32,422
|
---|
|
|
|
Manufacturer
| Langley
|
---|
Launch mass
| 9,724 kg (21,438 lb)
[1]
|
---|
Dry mass
| 3,629 kg (8,001 lb)
[1]
|
---|
|
|
|
Launch date
| April 6, 1984, 13:58:00
(
1984-04-06UTC13:58Z
)
UTC
|
---|
Rocket
| Space Shuttle
Challenger
STS-41-C
|
---|
Launch site
| Kennedy
LC-39A
|
---|
|
|
|
Recovered by
| Space Shuttle
Columbia
STS-32
|
---|
Recovery date
| January 12, 1990, 15:16
(
1990-01-12UTC15:17Z
)
UTC
|
---|
Landing date
| January 20, 1990, 09:35:37 UTC
|
---|
Landing site
| Edwards
Runway 22
|
---|
|
|
|
Reference system
| Geocentric
|
---|
Regime
| Low Earth
|
---|
Eccentricity
| 7.29E-4
|
---|
Perigee altitude
| 473.0 km (293.9 mi)
|
---|
Apogee altitude
| 483.0 km (300.1 mi)
|
---|
Inclination
| 28.5 degrees
|
---|
Period
| 94.2 minutes
|
---|
|
|
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]
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 LiSO
2
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
]
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
]
- ^
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
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edit
]
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Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in
underline
. Uncatalogued launch failures are listed in
italics
. Payloads deployed from other spacecraft are denoted in (brackets).
|