This morning, at about 1:00 am CET, ESA’s Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite reentered the atmosphere and burned up somewhere along its orbital path extending from Siberia, across the western Pacific Ocean, the eastern Indian Ocean, and to Antarctica. According to the space agency, it disintegrated in the upper atmosphere and though some debris may have reached the surface, no damage was reported.
Launched in March 2009 from Russian’s Plesetsk Cosmodrome, GOCE’s mission was to carry out the most detailed survey yet of the Earth’s gravitational field, within one-millionth of a gravity. The octagonal 1,100-kg (2,425-lb) satellite, nicknamed the "Ferrari of space," provided new insights into the Earth’s structure and the ocean’s circulation, as well as the creation of a map of the "geoid," which is the shape of an ideal global ocean as it would appear under only the influence of rotation and gravity, and not tides and wind.
In order to carry out these measurements, GOCE was placed in an orbit of 255 km (158 miles) to 224 km (139 miles). At this altitude, there is enough of the Earth’s atmosphere present to cause considerable drag, so the unmanned spacecraft was somewhat streamlined, and equipped with winglets and an ion engine to help it maintain orbit.
On October 2, GOCE’s engine ran out of xenon fuel, its orbit began to naturally decay, and it lost about 1.5 km (1 mile) of altitude per day. ESA’s Space Debris Office and the Inter-Agency Space Debris Coordination Committee monitored the spacecraft’s progress and continued to update its estimated time of reentry. On November 10 at about 11:50 pm, it was tracked by the Antarctic Troll station at an altitude of 120 km (75 miles) and ESA reported that the craft was, to the agency’s surprise, still functional. Then, at about 1:00 am, communications were lost as it made its final plunge into the atmosphere.
"The one-tonne GOCE satellite is only a small fraction of the 100 – 150 tonnes of man-made space objects that reenter Earth’s atmosphere annually," says Heiner Klinkrad, Head of ESA’s Space Debris Office. "In the 56 years of spaceflight, some 15,000 tonnes of man-made space objects have reentered the atmosphere without causing a single human injury to date."
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