Gerhard Drolshagen, (ESA/ESTEC/TEC-EES)
Keywords: Orbital Debris
Abstract:
Information on the small size (millimetre or smaller) space debris and meteoroid population in space can only be obtained by in-situ detectors or the analysis of retrieved hardware. Past, ongoing and planned ESA activities in this field are presented.
In 1996 the GORID impact detector was launched into a geostationary orbit on-board the Russian Express-2 telecommunication satellite. This impact ionisation detector had a sensor surface of 0.1 m2. Until July 2002 when the spacecraft was shut down it recorded more than 3000 impacts in the micrometre size range. Inter alia, GORID measured numerous clusters of events, believed to result from debris clouds, and indicated that debris fluxes in GEO are larger than predicted by present models. Another in-situ detector, DEBIE-1, was launched in October 2001 and is operating on-board the small technology satellite PROBA in a low polar orbit. It has two sensors, each of 0.01m2 size, pointing in different directions. A second detector of this type, DEBIE-2 with 3 sensors, is ready for flight on the EuTEF carrier (external payload to ISS). The data from GORID and DEBIE-1 are stored on-line in EDID (European Detector Impact Database).
Post-flight impact analyses of retrieved hardware provide detailed information on the encountered meteoroid and debris fluxes over a large range of sizes. ESA initiated several analyses in the past ((EURECA, Hubble Space Telescope (HST) solar arrays). The most recent impact analysis was performed for the HST solar arrays retrieved in March 2002. Measured crater sizes in solar cells ranged from about 1 micron to 7 mm. A total of 175 complete penetrations of the 0.7 mm thick arrays were observed. A chemical analysis of impact residues allowed the distinction between space debris and natural meteoroids. Space debris was found to dominate for sizes smaller than 10 microns and larger than about 1 mm. For intermediate sizes impacts are mainly from meteoroids. Results of the analysis and comparisons with model predictions are presented.
The paper concludes by presenting evidence for several unintended in-situ impacts which were encountered by the CCDs of the XMM-Newton x-ray telescope.
Date of Conference: September 10-14, 2006
Track: Orbital Debris