Last November, Russia launched the Phobos-Grunt spacecraft to explore Phobos, one of Mars's two moons. But the probe never reached its destination.
After its launch, Phobos-Grunt's rockets malfunctioned and failed to lift it out of low Earth orbit. The craft circled Earth for two months. During that time, atmospheric drag slowed the probe and caused it to drop lower and lower until it re-entered the atmosphere. As the 15-ton spacecraft sped toward Earth at 8 kilometers (5 miles) per second, it began to break apart and burn up.
People on the ground had little to fear from the falling probe. About 70 percent of Earth's surface is covered in water, so re-entry debris usually lands in the ocean. The remaining pieces of Phobos-Grunt, for example, landed in the Pacific. "In the entire history of space exploration, nobody has been injured by a piece of re-entry debris," says Eugene Stansbery of NASA's orbital-debris program.
THE PHOBOS-GRUNT SPACECRAFT
Phobos-Grunt was designed to collect and return soil samples from Mars's moon Phobos. It fell back to Earth before even beginning its three-year mission.
RETURN CAPSULE FOR SAMPLES:
Designed to survive re-entry into Earth's atmosphere
13,505 kilograms (15 tons)
November 8, 2011
BIGGEST SPACECRAFT RE-ENTRIES
The largest vehicle to crash to Earth was the 135-ton Mir space station, purposely pulled from orbit in 2001. Create a bar graph of the next largest uncontrolled re-entries, shown here, by weight.
Salyut 7/ Shuttle Cosmos Columbia Skylab 1686 NATION United States United States Russia RE-ENTRY DATE 2003 1979 1991 VEHICLE TYPE Space shuttle Space station Space station WEIGHT 100 tons 85 tons 44 tons LENGTH 37 m (122 ft) 36 m (118 ft) 31 m (102 ft)
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|Title Annotation:||EARTH: ASTRONOMY; crash of Phobos-Grunt spacecraft|
|Date:||Apr 16, 2012|
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