The European Space Agency GOCE Satellite has fallen to Earth, but thousands of pieces of “space junk” still float around up there.
Late on Sunday Nov. 10, ESA’s GOCE satellite descended towards the Earth in an orbit that passed over Siberia, the Pacific Ocean, the Indian Ocean, and Antarctica, before finally landing near the Falkland Islands. After GOCE ran out of fuel it made an uncontrolled reentry into the atmosphere, the first European Space Agency mission to do so in over 25 years. GOCE was seven feet long and just over three feet wide, and weighed 2,425 pounds, but most of it disintegrated in the atmosphere, leaving about a quarter of it to splash into the Atlantic ocean.
GOCE is short for Gravity Field and Steady-State Ocean Circulation Explorer, and was the first of three satellites that seek to map the Earth’s gravitational field as part of the European Space Agency Living Planet Programme. GOCE used a highly sensitive gradiometer to measure gravitational gradients along three axes. For over four years it was able to provide valuable data on ocean behavior that may help make predictions for climate changes. GOCE has also given scientists improved accuracy in calculating the geoid, which is the shape of the surface the oceans would take if no other forces were at work on it except for the gravitation and rotation of the Earth itself.
The Inter-Agency Space Debris Coordination Committee is the world forum on “space junk.” The organization used GOCE as its special study project this year, using tracking technology around the world to monitor the probe’s crash into the Earth. Dubbed the “Ferrari of space” because of its sexy fins, the one-ton GOCE used its magnetic control system and aerodynamic stability to remain stable until the final hours of its descent.
Somewhere between 100 to 150 tons of space junk reenter Earth’s atmosphere every year–at about a rate of one piece of space junk per day. In 56 years of space flight, about 15,000 tons of space junk have reentered Earth’s atmosphere without causing injury to a single person. In 2011, chunks of debris from a spacecraft rained over Germany, the Czech Republic, and the Netherlands, but no damage was recorded and none of the pieces were found. Of the 6,600 satellites that have been launched, 3,600 are still in space and about 2,600 of those are no longer in operation.
These are the largest spacecrafts to make an uncontrolled reentry into Earth’s atmosphere:
1979: NASA’s Skylab was an 85-ton space station that crashed into the Indian Ocean and Western Australia (the town of Eperance reportedly fined NASA $400 for littering.)
1979: NASA’s Pegasus 2 research satellite was 11.6 tons and fell into the mid-Atlantic in 1979.
1971: The Soviet Union’s Salyut 7 space station was 11 tons and rained down on Argentina.
1978: The 3.8-ton nuclear-powered Soviet Cosmos 954 spread radioactive debris over Northwestern Canada (Canada billed the USSR $6 million to clean it up, of which $3 million was paid.)
2003: NASA’s space shuttle Colombia broke apart over Northeastern Texas, incinerating all seven astronauts on board.
2011: NASA UARS was a decommissioned 6.5-ton research satellite that crashed into the southern Pacific ocean
2013: European Space Agency GOCE satellite is the latest piece of space junk to fall to Earth.
By K. Elsner