Long Duration Exposure Facility

Experiments on board the NASA Long Duration Exposure facility have been performed with spores from the bacterium Bacillus subtilis, allowing them to be exposed to the extreme conditions of space. Low pressures and highly energetic particles are dominant in space and most importantly around the Sun, including an intense UV radiation field. It is the latter that is the most destructive in terms of viability of the spores, and under controlled conditions the extreme UV exposure is four orders of magnitude more likely to kill the cells than when screened. Crucially, however, not all spores were killed. Protection of the spores from the UV field for example within the interior of the meteorite suggests that the spores... 

The remarkable stability of the cage structure makes fullerenes Important candidates for survival and wide distribution in space. Fullerenes of astronomical origin have been detected in meteorites and in and around an impact crater on the Long Duration Exposure Facility spacecraft (39). Laboratory simulations in combination with interstellar observations support the idea that the predominant fraction of carbon in space is present as solid macromolecular carbon (40) or amorphous and hydrogenated amorphous carbon (41). 

LDEF long duration exposure facility LOI limiting oxygen index... 

There are elements of the space environment that make it harsh on materials that are employed in space. The presence of atomic oxygen and the ever-present ultraviolet rays of the sun are dominant. Some of the very best scientific data on the survivability of materials in space come from experiments conducted on NASA s Long-Duration Exposure Facility (LDEF). Summaries of those data (7,5) reveal that atomic oxygen may be a major problem for materials that deteriorate upon oxidation. Most dramatic among the LDEF samples was the erosion of exposed carbon surfaces owing to the loss of surface carbon as CO and CO2. These results became design considerations. 

Pippin, H.G., Analysis of Materials Flown on the Long Duration Exposure Facility Summary of Results of the Materials Special Investigation Group , NASA CR, 1995. 

Fig. 9.9. NASA Long Duration Exposure Facility, unmanned, free-flying spacecraft. (Reproduced with permission from LDEF-69 Months in space, conference publication 3134, part 1 published by NASA.)...

In order to study the effects of space environment on different materials, including polymers [326, 450, 1326, 2314], NASA s Office of Aeronautics and Space Technology launched, in 1984, the Long Duration Exposure Facility (LDEF) unmanned, free-ffying spacecraft (Fig. 9.9) for long term (69 months) exposure to the space environment [1198, 1632]. 

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