Impact data from the Eureca post-flight analysis will therefore contribute to the validation and improvement of the current meteoroid and debris models for low Earth orbit.įigure 1 shows Eureca in the cargo bay of Space Shuttle 'Atlantis' prior to launch. This activity extends the analyses that NASA performed in the late eighties on the Solar Max, Palapa and Westar satellites and the Long-Duration Exposure Facility (LDEF), after they too had been recovered from space.Ĭompared to LDEF, Eureca has a large Sun-pointing surface, resulting in different types of meteoroid and debris impact signatures. Investigating the nature and the morphology of the impact features on ESA's European Retrievable Carrier 'Eureca' is therefore an exercise crucial to the understanding of the meteoroid and the evolving debris environments. After just a short period of exposure to the space environment, surfaces are covered with impacts from small pieces of debris and meteoroids. Knowledge of the solid-particle population of millimetre- and micron-sized particles is gained either from dedicated space experiments or through the analysis of material that has been returned from space. In addition, particle fluxes in space are also of considerable scientific interest. As a result of this threat, designers have to consider the risk of particle impacts in the planning of every space mission. Larger particles can penetrate the outer shielding of a spacecraft and can damage its internal equipment. Typical impact velocities are 10 km/s for space debris and 20 km/s for meteoroids. While the risk of collision with a large piece of debris or a large meteoroid is very small, particles less than one millimetre in size cause craters visible to the naked eye. These particles are a hazard for both long-term missions and large spacecraft. A much larger number of smaller man-made debris items and micrometeoroids that are orbiting the Earth cannot be detected from the ground. Currently more than 7000 large man-made objects orbiting in near-Earth space can be tracked from the ground with radar or by optical means. IntroductionĮvery spacecraft in Earth orbit is exposed to a flux of space debris and meteoroid particles. The detailed optical survey of all outer Eureca surfaces, which was the first main task of the impact analysis, has now been completed. With its fixed Sun-pointing attitude, large areas of identical surface materials, and 1992-1993 exposure period, Eureca has provided impact data that are complementary to those from LDEF. The retrieval of Eureca has given the Agency a rare opportunity to study the fluxes and resulting effects of meteoroid and space-debris impacts on exposed spacecraft surfaces in Low Earth Orbit (LEO). McDonnell Unispace Kent, United Kingdom T.Stevenson Mare Crisium, United Kingdom Drolshagen European Space Research & Technology Centre (ESTEC).
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