OPTICAL SURVEY OF MICROMETEOROID AND SPACE DEBRIS IMPACT FEATURES ON EURECA

The results of an optical survey of impact features from micrometeorid s and space debris on the EUropean REtrievable CArrier (EURECA) are pr esented. EURECA eas returned from space in June 1993 after almost 11 m onths in Low Earth Orbit. Impact features on all outer surfaces (mainl y Multi Layer Insulation blankets and front and rear sides of solar ar rays) were systematically recorded and measured. The size of recorded impact features ranges from about 30 mu m to 6.5 mm. High resolution m icro-photographs were taken from 932 of the larger impact sites. The v isibility of impacts differs largely for the different surfaces. Impac ts are most easily detected on the cover glass of the solar cells. On these surfaces the measured cumulative flux of impact craters with a c entral pit diameter of 50 mu m or larger is approximate to 1.5 x 10(-6 )/m(2) s(-1). On these glass surfaces, 225 out of 703 impacts which we re 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. Copyright (C) Else vier Science Ltd.