☰ Menu

Satellite hits Atlantic — but what about next one?

By David Rising
Associated Press

BERLIN: This time it splashed down in the Atlantic Ocean — but what about next time?

The European Space Agency says one of its research satellites re-entered the Earth’s atmosphere early Monday on an orbit that passed over Siberia, the western Pacific Ocean, the eastern Indian Ocean and Antarctica.

The 2,425-pound satellite disintegrated in the atmosphere but about 25 percent of it — about 600 pounds of “space junk” — slammed into the Atlantic between Antarctica and South America, a few hundred miles from the Falkland Islands, ESA said. It caused no known damage.

The satellite — called the GOCE, for Gravity field and Ocean Circulation Explorer — was launched in 2009 to map the Earth’s gravitational field. The satellite had been gradually descending in orbit over the last three weeks after running out of fuel Oct. 21.

But even with the satellite’s seemingly safe landing comes the question: How much space junk is out there and how dangerous is it?

Some 6,600 satellites have been launched. Some 3,600 remain in space but only about 1,000 are still operational, according to the European Space Agency. Not all are still intact, and the U.S. Space Surveillance Network tracks some 23,000 space objects, ESA said. A lot of junk comes down unnoticed, said ESA Space Debris Office deputy head Holger Krag. Statistically, he said, “roughly every week you have a re-entry like GOCE.”

According to Heiner Klinkrad, the head of ESA’s Space Debris Office, about 110 to 165 tons of space junk re-enters Earth’s atmosphere each year. In 56 years of spaceflight, a total of 16,500 tons of 
human-made space objects have re-entered the atmosphere.

Space junk — mostly satellites and rocket stages or fragments — typically travels at about 17,400 mph shortly before re-entry at about 75 miles above the Earth, according to ESA. It starts to slow down and heat up in the dense atmosphere. In the last 10 minutes, it hits a traveling speed roughly equal to that of a Formula One racing car — between 125 mph to 190 mph.

There have been no known human injuries or significant property damage caused by space junk, according to ESA. Unlike meteorites, which hurl into the Earth as solid chunks traveling about three times faster, space junk typically falls as fragments and is distributed over a fallout zone up to 600 miles long.

When systems are still functioning, spacecraft can be maneuvered to try to direct them to land in areas where there would be minimal impact, like into an ocean. The GOCE satellite’s systems kept working much longer than expected, providing data that Krag said will be invaluable in helping scientists figure out prediction models for future space junk descents.


Prev Next