Searching for small debris in the geostationary ring - Discoveries with the Zeiss 1-metre telescope

More than 800 satellites and rocket upper stages have been inserted into th e geostationary ring or its vicinity over the years, but only about 250 to 270 of these satellites are currently being used operationally. Geostationa ry satellites are therefore increasingly at risk of colliding with uncontro lled objects. Contrary to the situation with satellites at very low altitud e, there are no effective natural removal mechanisms for objects in Geostat ionary Earth Orbit (GEO). Ground-based radars and optical telescopes belong ing to the United States' Space Surveillance Network (SSN) are able routine ly to detect objects larger than 1 m across in GEO. ESA has recently upgrad ed a telescope at the Teide Observatory in Tenerife (E) with an optimised d ebris-detection system. Its early observations show a hitherto unknown but significant population of uncatalogued objects with diameters as small as 1 0 cm in the geostationary ring. Objects smaller than 10 cm are also expecte d to exist, but these are unobservable even with the 1 m Teide telescope. F urther observations are urgently needed to determine the extent and origin of this debris population, and the resulting hazard to operational spacecra ft.