A failed Russian probe designed to travel to a Mars moon but was stuck in Earth orbit will come crashing down within hours, likely in a shower of fragments that survive the fiery re-entry. The unmanned Phobos Ground, the most expensive since the Soviet era, is one of the heaviest and most toxic space derelicts ever to crash to Earth, but experts say the risks are minimal as its orbit is mostly over water and most of the probe's structure will burn up in the atmosphere anyway.
According to the latest reports from Russian space agency Roscosmos, the Phobos-Ground will crash between 1:50 pm and 2:34 pm EST. The probe could come down anywhere along its orbit that would place it over southern Europe, the Atlantic Ocean, South America and Pacific. The rest of the world, including the U.S. and Canada, is outside the risk zone.
Russia's space chief has acknowledged the $170-million Phobos-Ground mission was ill-prepared, but admitted they were forced to give it the go-ahead so as not to miss the limited Earth-to-Mars launch window. The Phobos-Ground mission is the latest in a long string of failures in the Russian space program.
Its predecessor, Mars-96, which was built by the same Moscow-based NPO Lavochkin company, also suffered an engine failure and crashed shortly after its launch in 1996. Its crash drew strong international fears because of some 200 grams of plutonium on board. The craft eventually showered its radioactive fragments over the Chile-Bolivia border in the Andes Mountains, and the pieces were never recovered.
The worst ever radiation spill from a derelict space vehicle came in January 1978 when the nuclear-powered Cosmos 954 satellite crashed over northwestern Canada. The Soviets claimed the craft completely burned up on re-entry, but a massive recovery effort by Canadian authorities recovered a dozen fragments, most of which were radioactive.
The Phobos-Ground also contains a tiny quantity of the radioactive metal Cobalt-57 in one of its instruments, but Russia has claimed it poses no threat of radioactive contamination.
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