Russia’s ill-fated Phobos-Grunt spacecraft fell from orbit on Sunday, although there was some confusion as to where any fragments surviving reentry may have landed.
Russia’s Aerospace Defence Forces reported that debris from the 14-ton craft landed in the southern Pacific ocean, in a remote area about 775 miles (1250 km) west of Chile. Russian ballistics experts, however, cited a location in the Atlantic, off the coast of Brazil.
Launched November 9, the probe was intended to land on the Martian moon Phobos and return soil and rock samples to Earth.
Instead, the craft was stranded in an erratic, low-Earth orbit when booster engines that should have broken it free from Earth gravity failed to ignite. The failure was followed by several weeks of unsuccessful attempts to reestablish contact with the craft.
The probe’s fuel tanks, filled with 11 tons of highly toxic fuel needed to propel the craft to Mars and back, were initially the cause of some environmental concern. However, because the tanks were made of aluminum, they are virtually certain to have been incinerated during reentry. Had they been constructed of titanium like those used in the recently retired U.S. Space Shuttle, the chances of surviving reentry would have been significantly greater.
Russian space officials predicted that 20-30 fragments would reach the surface, weighing no more than 200 kg in total. A small amount of radioactive cobalt that was on board was deemed too insignificant to cause environmental damage even if it did survive reentry.
The discrepancy over landing sites reflects the confusion that has surrounded the mission since shortly after launch. When its boosters first failed to fire, Russian space officials were unable to locate the craft at all and, as recently this week, predictions of where it might land varied wildly.
Wednesday, the Russian space agency expected debris would land in the Indian Ocean, then revised their prediction to the Mozambique Channel between Madagascar and the eastern coast of Africa. Friday, they were predicting a landing site near the Falkland Islands, off the Atlantic coast of Argentina. Saturday’s prediction — in the Pacific off the western coast of Chile — was apparently the closest, but at the last minute, that too was revised in favor of a remote spot in China’s Gobe Desert.
According to NASA, the $165 million Phobos-Grunt marks Russia’s 17th Mars mission and 17th failure dating back to 1960.
Phobos-Grunt is one of the largest manmade objects to fall from orbit since the Russian space station MIR was intentionally brought down in 2001.
No confirmed injuries from falling spacecraft debris have ever been reported.