Humans have always had a propensity to leave evidence of their presence but rarely has our littering posed as significant a risk to our future activities as the junk that now circulates in orbit around our planet. According to a report by the US National Research Council Committee for the Assessment of NASA’s Orbital Debris Programs, the amount of satellite and rocket debris orbiting the earth has now reached a “tipping point”, by which the Committee means that the debris will continually collide with itself, further increasing the population of orbital debris. The Committee states that “This increase will lead to corresponding increases in spacecraft failures, which will only create more feedback into the system, increasing the debris population growth rate.”

The report reviews measures to assess the risk of harm to humans from falling debris and in many areas it finds current programs inadequate. In particular, it finds that “Enhanced mitigation standards or removal of orbital debris are likely to be necessary to limit the growth in the orbital debris population.” However, the necessary economic, technology, testing, political, or legal considerations for removal of orbital debris have not been fully examined.

As we approach the uncontrolled return of the failed Russian Mars mission in a few days, this NRC report suggests that some of the risk assurances given by the media are not well grounded. It also provides numerous recommendations for more research, as well as technology development and deployment that is needed if we are to ensure that future risks from uncontrolled space junk are manageable.

For a copy of the full report visit http://www.nap.edu/catalog.php?record_id=13244