NASA Technical Reports Server (NTRS) : LDEF pdf

NASA Technical Reports Server (NTRS) : LDEF

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Two impact craters found in Al from the Long Duration Exposure Facility (LDEF) experiment tray have residues concentrated in the bottoms, along the walls, and on top of overturned rims. Analyses indicate a ‘chondritic’ compositional signature (Si, S, Ca, Fe, Mg, and Ni) for the bulk residue. In one crater (number 74), round to irregular silicate grains are overlain by carbon. In addition, carbon also partially covers the crater walls, the top of the raised overturned rim, and extends outward from the crater. The second crater (number 31) also contains carbon with similar distribution in and about the crater, although the silicate residue appears to be glassy. Silver, I, K, and F (possibly some of the Ca, S, and Cl) appear to be contaminants as well as analyzed aromatic carbonaceous species associated with the raised rim and the area surrounding the crater. The origin of the impactors is assumed to be extraterrestrial.

The existence of impactor residue in two craters implies impact velocities less than or equal to 6 km, based on experimental hypervelocity studies

• Creator/s: NASA Technical Reports Server (NTRS
• Date: 1/1/1992
• Year: 1992
• Book Topics/Themes: NASA Technical Reports Server (NTRS), CARBON, CHONDRITES, CONTAMINANTS, CRATERS, IMPACTORS, LONG DURATION EXPOSURE FACILITY, RESIDUES, SIGNATURES, GLASS, RIMS, SILICATES, SILVER, TRAYS, WALLS, Bunch, T. E., Dibrozolo, F. Radicati, Fleming, Ronald H., Harris, David W., Brownlee, Don, Reilly, Terrence W

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