A Russian space probe designed to boost the nation's pride on a mission to Mars mystery-moon, Phobos, came to Earth showering fragments into the south Pacific west of Chile's coast, Russian officials said.
Pieces from the Phobos-Ground, which had become stuck in Earth's orbit, landed in water 1,250 kilometers (775 miles) west of Wellington Island in Chile's south, the Russian military Air and Space Defense Forces said in a statement carried by the country's news agencies.
The military space tracking facilities were monitoring the probe's crash, its spokesman Col. Alexei Zolotukhin said. Zolotukhin said the deserted ocean area is where Russia guides its discarded space cargo ships serving the International Space Station.
RIA Novosti news agency, however, cited Russian ballistic experts who said the fragments fell over a wider patch of Earth's surface, spreading from the Atlantic and including the territory of Brazil. It said the midpoint of the crash zone was located in the Brazilian state of Goias.
The spacecraft was intended to land on the crater-dented, potato-shaped Martian moon, collect soil samples and fly them back to Earth, giving scientists unique materials that could shed more light on the genesis of the solar system.
The unmanned Phobos Ground is one of the heaviest and most toxic space derelicts ever to crash to Earth, but European and Russian space officials and 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. The Phobos-Ground also contains a tiny quantity of the radioactive metal Cobalt-57 in one of its instruments, but Roscosmos said it poses no threat of radioactive contamination.
"The resulting risk isn't significant," said Prof. Heiner Klinkrad, Head of The European Space Agency's Space Debris Office that is monitoring the probe's descent.
Roscosmos predicts that only between 20 and 30 fragments of the Phobos probe with a total weight of up to 200 kilograms (440 pounds) will survive the re-entry and plummet to Earth.
The Phobos-Ground weighs 13.5 metric tons (14.9 tons), and that includes a load of 11 metric tons (12 tons) of highly toxic rocket fuel intended for the long journey to the Martian moon of Phobos. It has been left unused as the probe got stuck in orbit around Earth shortly after its Nov. 9 launch.
Roscosmos says all of the fuel will burn up on re-entry, a forecast Klinkrad said was supported by calculations done by NASA and the ESA. He said the craft's tanks are made of aluminum alloy that has a very low melting temperature, and they will burst at an altitude of more than 100 kilometers.
Russia's space chief has acknowledged the Phobos-Ground mission was ill-prepared, but said that Roscosmos had to give it the go-ahead so as not to miss the limited Earth-to-Mars launch window.
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 onboard. The craft eventually showered its 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.