Chapter 71. Hypervelocity Micrometeorite Damage in Fused Silica Space Shuttle Windows

  1. J. P. Singh
  1. J. Lankford1,
  2. K. Edelstein2 and
  3. Lyndon B. Johnson2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470294437.ch71

Proceedings of the 21st Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 18, Issue 3

Proceedings of the 21st Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 18, Issue 3

How to Cite

Lankford, J., Edelstein, K. and Johnson, L. B. (1997) Hypervelocity Micrometeorite Damage in Fused Silica Space Shuttle Windows, in Proceedings of the 21st Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: A: Ceramic Engineering and Science Proceedings, Volume 18, Issue 3 (ed J. P. Singh), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294437.ch71

Author Information

  1. 1

    Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238–5166

  2. 2

    Space Center, NASA Road 1, Houston, TX 77058

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 1997

ISBN Information

Print ISBN: 9780470375495

Online ISBN: 9780470294437

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Keywords:

  • space shuttle;
  • hypervelocity;
  • expand circumferentially;
  • residual strength;
  • lateral cracks

Summary

Thermal protection windows of fused silica on the space shuttle are subject to hypervelocity impacts by microscopic meteorites. Because of the extreme nature of these events, where velocities may reach 14 km/s, the resulting damage is qualitatively different from that produced under quasistatic or even normal high velocity (several hundred m/s) conditions. In particular, unusual “petaloid” cracking patterns are observed, whereby half penny-shaped cracks appear to nucleate on the base of the impact crater. These expand circumferentially (like Hertzian cracks), and then grow into the glass, curving outward continuously until they form one or more large lateral cracks attached to, but “floating” below, the crater. Also observed are smaller circumferentially-tangent half penny surface cracks located outside of the crater area. These several flaw types are characterized qualitatively and quantitatively, and correlated with crater dimensions (impact energy). Implications for window residual strength are noted.