Optical survey of micrometeoroid and space debris impact features on EURECA

Abstract

The results of an optical survey of impact features from micrometeoroids and space debris on the EUropean REtrievable CArrier (EURECA) are presented. EURECA was returned from space in June 1993 after almost 11 months in Low Earth Orbit. Impact features on all outer surfaces (mainly Multi Layer Insulation blankets and front and rear sides of solar arrays) were systematically recorded and measured. The size of recorded impact features ranges from about 30 μm to 6.5 mm. High resolution microphotographs were taken from 932 of the larger impact sites. The visibility of impacts differs largely for the different surfaces. Impacts are most easily detected on the cover glass of the solar cells. On these surfaces the measured cumulative flux of impact craters with a central pit diameter of 50 μm or larger is ≈1.5×10 −6/m 2s −1. On these glass surfaces, 225 out of 703 impacta which were measured in detail showed signs of directionality. The measurements, derived impact fluxes and a first evaluation of more detailed impact feature parameters and correlations are presented.