Главная Новости ПулКОН РСДБ Обсерватории Публикации About us Контакт

Space Debris Office


by R. Choc and R. Jehn

Produced with the DISCOS Database

February 2009
ESOC Robert-Bosch-Str. 5, 64293 Darmstadt, Germany

<<< Contents

7. Summary

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:
  • eccentricity smaller than 0.1
  • mean motion between 0.9 and 1.1 revolution per sideral day, corresponding to a semi-major axis between 42164 - 2500 km and 42164 + 3150 km.
  • inclination lower than 30 degrees

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:
  • 381 are controlled (251 under longitude and inclination control),
  • 476 are in a drift orbit,
  • 154 are in a libration orbit,
  • 103 are uncontrolled with no orbital elements available,
  • 5 could not be classified (six of them were recently launched and are en route to their longitude slot).
  • 67 are uncatalogued objects but which can be associated to a launch

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:
  • Marisat 3 (76101A, US, 330 x 1205 km)
  • Optus A3 (87078A, Australia, 350 x 425 km)
  • Optus B1 (92054A, Australia, 275 x 330 km)
  • Superbird A1 (92084A, Japan, 290 x 365 km)
  • Orion 1 (94079A, US, 390 x 570 km)
  • Skynet 4D (98002A, Great Britain, 305 x 330 km)

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.
  • PAS 6B (98075A, US) 241 x 393 km above GEO

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:
  • Galaxy 10R (0002A, US) 170 x 190 km above GEO

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:
  • Gorizont 28 (93069A, Russia) around L1
  • Echostar 2 (96055A, US) around L2
  • Gorizont 33 (00029A, Russia) around L1 and L2
  • Xinnuo 2 (06048A, China) around L1

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.
8. References
1. Samsom P., "Classification of Geostationary Objects", ESOC - MAS WP 420, 1999.
9. Acknowledgements
The authors thank Nicholas Johnson and Vladimir Agapov for their suggestions and valuable contributions.

Главная Новости ПулКОН РСДБ Обсерватории Публикации About us Контакт