EUROPEAN SPACE AGENCY
EUROPEAN SPACE OPERATIONS CENTRE
GROUND SYSTEMS ENGINEERING DEPARTMENT
Space Debris Office
CLASSIFICATION OF GEOSYNCHRONOUS OBJECTS
All geostationary or near-geostationary objects catalogued in ESA’s DISCOS Database (Database and Information System Characterising Objects in Space) are listed in this document. An object is considered as geostationary or near-geostationary if it meets the following criteria:
970 objects met these criteria as of 31 December 2008. 216 more objects are also known to be in this orbital region although no orbital elements are available in DISCOS. Thus, the total number of known objects in the geostationary region is 1186. They can be classified as follows:
Additionally we have orbits for 152 unidentified objects. Some of those belong to objects where no TLEs are available but which are already included in the total number of 1186.
Compared with the last issue of January 2008 the following changes can be observed: There were 33 new objects (29 payloads and 4 rocket bodies) launched into or near GEO during the last year. Three objects (69045A, 97040A and 06053D) had not been included in the previous reports for various reasons. Thus the total number of objects increased by 36 (from 1150 to 1186).
12 spacecraft reached end of life as far as it can be inferred from the orbital elements stored in DISCOS or declared by spacecraft operators. 6 were reorbited more than 275 km above GEO and therefore complied with the IADC reorbiting guidelines:
One spacecraft was reorbited into a graveyard orbit with a perigee 241 km above GEO. A forward propagation over 200 years showed that it will not enter the 200-km protected zone around GEO. Therefore, it is also complying with the IADC guidelines.
One spacecraft was reorbited too low. It suffered primary and secondary propulsion system malfunctions prior to 2005 and was unable in 2008 to reach a higher disposal orbit:
Echostar 2 suffered a catastrophic malfunction in 2008 and could not be manoeuvred at all. Also three other spacecraft seem to be abandoned. These four spacecraft have started librating around the libration points:
There was a failure of the classified US satellite USA 197 (DSP F23, 07054A, UI 141). It is now librating around the Eastern libration point.
This analysis has shown that in 2008, eleven years after the IADC guidelines were established, there are still too many satellites that were not or could not be properly reorbited.
Besides the improper reorbiting of aging satellites, also the release of rocket bodies still is a concern in GEO. The Proton-K fourth stage (Block DM-2M, 08033D, Russia) from the Cosmos 2440 launch which ended up in a libration orbit clearly violates the IADC guidelines. Also the Zenith-3SLB third stage (Block DM-SLB, 08022B, Russia) from the Amos 3 launch crosses the geostationary ring every day (perigee 800 km below and apogee 3600 km above GEO). The Briz M upper stage (08003B, Russia) from the Ekspress AM-33 launch and the apogee kick motor of Feng Yun 2E (08066C, China) are currently sufficiently below the geostationary ring (apogee 247 and 340 km below GEO, respectively). A long-term orbital propagation is required, especially for the Briz M upper stage, to check if it will not drift into the 200 km protected zone around GEO.
1. Samsom P., "Classification of Geostationary Objects", ESOC - MAS WP 420, 1999.
The authors thank Nicholas Johnson and Vladimir Agapov for their suggestions and valuable contributions.