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Satellite remains splash down into Atlantic Ocean
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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 yesterday on an orbit that passed over Siberia, the western Pacific Ocean, the eastern Indian Ocean and Antarctica.
The 1,100-kilogram satellite disintegrated in the atmosphere but about 25 percent of it — about 275 kilograms of “space junk” — slammed into the Atlantic between Antarctica and South America, a few hundred kilometers from the Falkland Islands, ESA said. It caused no known damage.
The satellite was launched in 2009 to map the Earth’s gravitational field. The information is being used to understand ocean circulation, sea levels, ice dynamics and the Earth’s interior. The satellite had been gradually descending in orbit over the last three weeks after running out of fuel on October 21.
But how much space junk is out there? Here’s a look:
Satellites in orbit
Some 6,600 satellites have been launched. Some 3,600 remain in space but only about 1,000 are still operational, according to ESA. Not all are intact, and the US 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.”
When it starts to fall
About 100 to 150 tons of space junk re-enters Earth’s atmosphere each year, according to Heiner Klinkrad, the head of ESA’s Space Debris Office. In 56 years of spaceflight, a total of 15,000 tons of human-made space objects have re-entered the atmosphere.
At what speed does space junk travel?
Space junk — mostly satellites and rocket stages or fragments — typically travels at about 28,000 kilometer/hour shortly before re-entry at about 120km 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 200kph to 300kph.
How dangerous is it?
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 1,000 kilometers long. Krag says fragments from a satellite came down in 2011 over the Netherlands, Germany and the Czech Republic but no pieces were ever found.
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