Space junk 'at tipping point'
The amount of debris orbiting the Earth has reached "a tipping point" for collisions, which would in turn generate more of the debris that threatens astronauts and satellites.
Nasa needs a new strategic plan for mitigating the hazards posed by spent rocket bodies, discarded satellites and thousands of other pieces of junk flying around the planet at speeds of 28,164km/h, the US National Research Council said in a study published yesterday.
The council is one of the private, non-profit US national academies that provide expert advice on scientific problems.
Orbital debris poses a threat to the approximately 1,000 operational commercial, military and civilian satellites orbiting the Earth - part of a global industry that generated $168 billion in revenues last year, Satellite Industry Association figures show.
The world's first space collision occurred in 2009 when a working Iridium communications satellite and a non-operational Russian satellite collided 789km over Siberia, generating thousands of new pieces of orbital debris.
The crash followed China's destruction in 2007 of one of its defunct weather satellites as part of a widely condemned anti-satellite missile test.
The amount of orbital debris tracked by the US Space Surveillance Network jumped from 9,949 objects in December 2006 to 16,094 in July 2011, with nearly 20 per cent of the objects stemming from the destruction of the Chinese Fengyun 1-C satellite, the research council said.
The surveillance network tracks objects of about 10cm in diameter and larger.
Some computer models show the amount of orbital debris "has reached a tipping point, with enough currently in orbit to continually collide and create even more debris, raising the risk of spacecraft failures," the council said in a statement released as part the 182-page report.
In addition to more than 30 findings, the panel made two dozen recommendations for Nasa to mitigate and improve the orbital debris environment, including collaborating with the US state department to develop the legal and regulatory framework for removing junk from space.
Current international legal principles, for example, ban nations from salvaging or otherwise collecting other nations' space objects.
The study, Limiting Future Collision Risk to Spacecraft: An Assessment of Nasa's Meteoroid and Orbital Debris Programs, was sponsored by Nasa.