Micrometeorite impact craters on Skylab EXPERIMENT S-149
Five craters between 1 and 30 μm. These craters show clear signs of hypervelocity impact. Measurements yielded diameter to depth ratios between 2 and 3. Chemical investigations in the craters yielded an enhancement in aluminium in one case.
44 crater-like structures between 1 and 4 μm in diameter. These features have been found on 4 cm2 of pyroxene exposed in solar direction. They show diameter to depth ratios between 5 and 8. Chemical measurements of the interior of these structures indicate the elements of the pyroxene composition.
The five impacts of the it t group correspond to a c mulative flux of the order of 10−4 (m−2 s−1) for masses of about 10−12 g. The second group may indicate a fragmentation process at altitudes around 450 km. Considering these 44 crater-like structures having been produced by fragments of one projectile, the impact rate could be comparable to that calculated for the first group. If individual projectiles had produced these structures, the corresponding flux could be 2 orders of magnitude higher.
KeywordsPhosphate Glass Depth Ratio Large Crater Collection Surface Pyroxene Composition
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