Space Security Index

Space Security 2011
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(UARS), 60 which had also shed four pieces in November 2007. 61 On 25 October, 10 days
before the piece of debris was predicted to reenter the Earth’s atmosphere, it was deemed
to have a greater than 1-in-10,000 chance of colliding with the ISS the following day. e
ISS maneuvered approximately two hours before the predicted time of closest approach on
26 October. e ISS usually maneuvers several times a year to avoid close approaches with
space debris, although these maneuvers are combined with required orbit-raising maneuvers
when possible.
NASA also reported that, in 2010, seven collision avoidance maneuvers were conducted by
ve of its satellites: Terra, Cloudsat, Landsat 5, Aura, and Landsat 7. 62 All orbit at an altitude
of approximately 720 km, which is the most densely populated region. In 2009, six NASA
satellites made a total of seven collision avoidance maneuvers. 63 ESA reported that it had
conducted nine collision-avoidance maneuvers in 2010 to protect its operational satellites. 64
e French space agency CNES reported that the 17-18 satellites it protects had performed
13 collision-avoidance maneuvers in 2010. 65
Speaking at the annual United States Strategic Command (USSTRATCOM) Strategic
Space Symposium in Omaha, Nebraska in November, Lieutenant General Larry James
said that, on average, the JSpOC sends out 190 conjunction warnings per week to satellite
owner/operators around the world. Based on these warnings, active satellites are performing
an average of three maneuvers a week to minimize the chances of colliding with another
object. is is a signicant increase from the 32 maneuvers reported between February and
December of 2009. 66
During the 4th International Association for the Advancement of Space Safety Conference
in May, Dr. William Ailor from the Aerospace Corporation presented a new report that
quantied the cost impact of space debris on space operations. 67 Entitled “Space Debris and
the Cost of Space Operations”, the report specically estimated the costs associated with
maintaining three types of satellite constellations in 850-km Sun-synchronous orbits from
2010 to 2030 due to increased amounts of space debris. e report found that the cost of
maintaining a small constellation of robust, short-lived, government-owned satellites would
increase by 5 per cent over the 20-year period, compared to the costs of maintaining the same
constellation in today’s debris environment. e cost of maintaining a large constellation of
cheaper, long-lived commercial satellites would increase by 26 per cent.
2010 Development
Compliance with international space debris mitigation guidelines is still inconsistent
During 2010, four satellites from the Globalstar constellation were reorbited to post-mission
disposal orbits above 2,000 km. 68 Between 1998 and 2000, 52 Globalstar satellites were
launched to create a LEO constellation that provided satellite phone and low-speed data
services. 69 Of these, most have reached their operational end-of-life, and 14 have been
reorbited above 1,600 km in accordance with U.S. and some international debris mitigation
guidelines. 70 However, the Inter-Agency Space Debris Coordination Committee (IADC)
guidelines do state that deorbiting of spacecraft is always the rst priority. Reorbiting should
only be considered when deorbiting is not possible, and spacecraft reorbited out of LEO
should be left above 2,000 km. 71
NASA conducted a series of 20 maneuvers during June and July to move its Ice, Cloud, and
land Elevation Satellite (ICESat) from its operational 600-km orbit to a 200 km x 280 km
disposal orbit. e satellite was then passivated and uneventfully reentered the atmosphere