Low-earth-orbit micrometeoroid and debris investigations

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 gears aboard the NASA Long Duration Exposure Facility and the Mir Orbital Station were retrieved. The samples were scanned to examine crater/perforation morphology and size distributions. The predicted flux on both experiments also was modeled using Kessler's debris and Grun's meteoroid distributions. To interpret the flux observed by the experiments, impact equations mere 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 influence of impact angle upon crater morphology. The results of the simulations together with the flux distribution on the Mir experiment indicated that secondary impacting might have occurred. Even without secondary impacts, the flux on Mir was significantly higher than model predictions.