OBJECT FLUX CHARACTERISTICS DUE TO VARIOUS TYPES OF DEBRIS SOURCES

摘要

The updated ESA MASTER model represents a high resolution debris analysis tool considering the major known sources of orbital debris down to 1 μm in diameter, i.e. debris generated by fragmentation, solid rocket motor firings, NaK droplets released by nuclear reactors in space, surface degradation particles, ejecta due to impacts of small particles on spacecraft surfaces, and meteoroids including the time dependent streams. All debris sources are considered from LEO up to the geosynchronous region. The object flux characteristics due to various types of debris sources are discussed in detail. Depending on the type of the target orbit, there are distinct source related size, impact velocity and impact direction distributions. Various orientations of the surfaces of a space craft within a defined co-ordinate system (earth-oriented, sun-oriented, inertial fixed) are considered. For the first time, the model provides an impression of possible flux characteristics in the GEO region down to 1 μm in size. Examples are given how projectile mass, material, velocity and direction depends on the target mission altitude and inclination. The detailed knowledge of the object flux characteristics is useful for a state of the art risk analysis for missions and for optimised protection of spacecraft, manned and unmanned.