Distinguishing the populations of natural meteoroids and space debris by GORID in geostationary orbit

Abstract

The Geostationary Orbit Impact Detector, GORID, is a dust impact plasma detector flying aboard the Russian Express-2 telecommunications spacecraft in geostationary orbit. The detector is the flight spare instrument of the successful Ulysses interplanetary dust detector which has contributed major results such as the detection of interstellar dust within our solar system. GORID is an active sensor, returning time resolved impact data, with approximate mass and direction information, from a rather different environment to interplanetary space. The geostationary ring is likely to be populated by a significant component of orbital debris, and data returned so far have shown some unusual characteristics, interpreted as relatively slow, large, highly charged debris particles. The data also appear to show diurnal and seasonal effects probably correlated with natural meteoroids and the detector's time dependent exposure geometry. This paper investigates the orbits of debris and meteoroids that the detector can sample as a function of time of day and time of year, in order to help the analysis of the GORID data.