Low-Earth-Orbit Micrometeoroid and Debris Investigations

Abstract

The aim of this work is to improve current knowledge of micrometeoroids and orbital debris in low Earth orbit using space detection experiments. In 1990 and 1993, a series of samples exposed to the space environment for several years aboard the NASA Long Duration Exposure Facility and the Mir Orbital Station were retrieved. The samples were scanned to examine crater/perforationmorphologyand size distributions. The predicted  ux on both experiments also wasmodeledusingKessler’s debris andGrun’s meteoroid distributions.To interpret the  ux observed by the experiments, impact equations were needed to convert observed crater dimensions to impacting particle dimensions. Simulation experiments carried out in the laboratory showed that the Cour-Palais empirical equation was suitable. Further experiments demonstrated the in uence of impact angle upon crater morphology. The results of the simulations together with the  ux distribution on the Mir experiment indicated that secondary impacting might have occurred. Even without secondary impacts, the  ux on Mir was signiŽ cantly higher than model predictions.