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Experiment Title: The Chemistry of Micrometeoroids

Original Principal Investigator(s): Brownlee, Donald - Invest. Role: Original, McKay, David - Invest. Role: Original, Housley, Robert - Invest. Role: Original, Morrisson, Donald - Invest. Role: Original, Horz, Dr. Friedrich - Invest. Role: Original, Horz, Dr. Friedrich - Invest. Role: Present,

The mineralogy, petrography, and chemistry of both primitive and more evolved meteorites recovered on Earth are currently the subjects of intense laboratory studies. The purpose of these studies, in conjunction with our knowledge of terrestrial and lunar petrogenesis, has been to establish an observational framework that can be used progressively to constrain and refine cosmochemical and mechanical-dynamic models of early solar-system evolutionary processes. Such modeling attempts include the nature and kinetics of nebular condensation and fractionation, the accretion of solid matter into planets, the differentiation and crustal evolution of planets, and the role of collisional processes in planetary formation and surface evolution. All of these processes are known to be highly complex.

Fine-grained interplanetary particles (micrometeoroids) of masses as little as 10(-16) g are, however, largely excluded from models of the early solar-system evolution because their mineralogic, petrographic, and geochemical nature is largely unknown. In comparison, however, their dynamics, orbital parameters, and total flux are reasonably well established, although still fragmentary in a quantitative sense. According to current (largely dynamical) hypotheses, a majority of these objects are derived from comets. This association affords a unique opportunity to study early solar system processes at relatively large radial distances from the Sun (less than approximately 20 AU). These cometary solids may reflect pressure and temperature conditions in the solar nebula which are not represented by any of the presently known meteorite classes, and therefore may offer potential insight into the formation of comets themselves.

Since LDEF was gravity-gradient stabilized and directionally stable (i.e. no rotation), the effects of each of the environments can be distinguished via changes in material response to hypervelocity impacts. The characterization of these affected areas will provide spacecraft system designers with the information they require to determine degradation of thermal control systems during satellite lifetimes.

Photograph Classification: Postflight

Associated Photograph(s):
LaRC - L91-07553
KSC - KSC-390C-1764.10
JSC - None
LaRC - L90-10438
KSC - None
JSC - S32-78-058
LaRC - L90-10414
KSC - None
JSC - S32-77-055
LaRC - L84-07366
KSC - KSC-384C-300.06
JSC - None
LaRC - L91-07805
KSC - KSC-390C-1697.10
JSC - None
LaRC - L89-04413
KSC - KSC-384C-538.01
JSC - None
LaRC - L91-07590
KSC - KSC-390C-1843.08
JSC - None

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