Radioactive Russian satellite could plunge to Earth in December

November 14, 2011 – MOSCOW – As Russian engineers battle to regain control of an ailing Mars moon probe stuck in Earth orbit, the chances of salvaging the spacecraft’s ambitious mission appear to be dwindling, according to Russian news reports. Attempts to contact the beleaguered Phobos-Grunt spacecraft overnight Thursday (Nov. 10) have failed, and the spacecraft could fall back to Earth around Dec. 3, a Russian space industry spokesman told the country’s Ria Novosti news service. “The spacecraft repeatedly passed over the Baikonur station and other Russian and foreign points of space communications during the night. There is no news yet,” the Ria Novosti quoted the unnamed spokesperson as saying. Russia’s official Federal Space Agency (Roscosmos) has not posted an update on Phobos-Grunt’s status to its website since Nov. 9, one day after the probe launched into space from Baikonur Cosmodrome in Kazakhstan. –Space

Legal liabilities and risk assessment: The reentry of Phobos-Grunt, like the reentry of UARS and ROSAT, presents the potential to cause damage on the surface of the Earth, but in contrast to the other two spacecraft, Phobos-Grunt presents a more dangerous scenario. It is possible that fuel within the spacecraft’s tanks could survive reentry, which potentially makes Phobos-Grunt a greater threat to the public than the reentry of the USA 193 reconnaissance satellite, which was shot down by an American SM-3 missile in 2008 to avoid an uncontrolled fall back to Earth.  Most experts believe the fuel will likely stay liquid if the probe explodes at an altitude of about 80 kilometers (50 miles). However, if some of the fuel is frozen it could survive reentry and be released on impact.  If surviving fuel tanks from the spacecraft impact on land or, worse, in a populated area, the resulting contamination could cause significant damage to the environment as well as to persons and property. In addition to the potential for contamination from surviving fuel, there is also concern about the cobalt-57 onboard the spacecraft, which is intended as a gamma ray source for the probe’s soil spectrometers. While the amount of material is reportedly small, its mere presence raises the specter of Cosmos 954 and its contamination of an area in the Canadian Northwest 1979. –Space Review

contribution by Amy P.