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Micrometeorite impact craters on Skylab EXPERIMENT S-149

  • K. Nagel
  • H. Fechtig
  • E. Schneider
  • G. Neukum
2 In Measurement of Interplanetary Dust 2.3 Particle Collection Experiments and Their Interpretation
Part of the Lecture Notes in Physics book series (LNP, volume 48)

Abstract

During the Skylab experiment S 149 three different sets of areas were exposed. 71.5 cm2 were facing the sun for 46 days, and 36 cm2 for 33 days, whereas 77.5 cm2 were exposed in anti-solar direction for 34 days. A fourth set is currently being exposed with the hope of future recovery. The exposed surfaces consisted of stainless steel, aluminium, platinum, glass, and pyroxene. The recovered targets have been investigated with a light microscope and a scanning electron microscope. We found two groups of possible impact structures:
  1. 1.)

    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.

     
  2. 2.)

    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.

Keywords

Phosphate Glass Depth Ratio Large Crater Collection Surface Pyroxene Composition 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Bedford, D.K., Adams, N.G., and Smith, D. (1975), “The Flux and Spatial Distribution of Micrometeoroids in the Near-Earth Environment”, Planet. Space Sci. 23, 1451.Google Scholar
  2. Fechtig, H., and Hemenway, C.L. (1976), “Near Earth Fragmentation of Cosmic Dust”, this Volume.Google Scholar
  3. Hemenway, C.L., Hallgren, D.S., and Tackett, C.D. (1974), “Near Earth Cosmic Dust Results from 5-149”, AIAA/AGU Conference on Scientific Experiments of Skylab, Huntsville, Alabama.Google Scholar
  4. Hoffmann, H.-J., Fechtig, H., Grün, E., and Kissel, J. (1975a), “First Results of the Micrometeoroid Experiment S 215 on the HEOS 2 Satellite”, Planet. Space Sci. 23, 215.Google Scholar
  5. Hoffmann, H.-J., Fechtig, H., Grün, E., and Kissel, J. (1975b), “Temporal Fluctuations and Anisotropy of the Micrometeoroid Flux in the Earth-Moon System Measured by HEOS 2”, Planet. Space Sci. 23, 981.Google Scholar
  6. Nagel, K., Neukum, G., Eichhorn, G., Fechtig, H., Müller, O., and Schneider, E. (1975), “Dependencies of Microcrater Formation on Impact Parameters”, VIth Lunar Science Conference, Houston, 1975. To be published in the Proceedings of the VIth Lunar Science Conference, Vol. 3, p. 3417.Google Scholar

Copyright information

© Springer-Verlag 1976

Authors and Affiliations

  • K. Nagel
    • 1
  • H. Fechtig
    • 1
  • E. Schneider
    • 1
  • G. Neukum
    • 1
  1. 1.Max-Planck-Institut für KernphysikHeidelbergGermany

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