Google – AFP, 11 November 2013
 |
Undated
artists impression of the Gravity field and steady-state Ocean Circulation
Explorer satellite which was placed in orbit in 2009 on a mission to monitor
variations
in gravity and sea levels (ESA - AOES Medialab/AFP/File)
|
Paris — A
spent science satellite that had measured Earth's gravity field reentered the
atmosphere on Sunday night and mostly disintegrated as planned, the European
Space Agency (ESA) said Monday.
As
expected, an estimated 25 percent of the one-tonne GOCE satellite reached the
Earth's surface, said an ESA statement, but "no damage to property has
been reported".
It did not
say where the fragments hit.
GOCE
"is only a small fraction of the 100-150 tonnes of man-made space objects
that reenter Earth's atmosphere annually," said 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."
Scientists
had predicted that several dozen fragments of GOCE, totalling some 200
kilogrammes (440 pounds) -- about the weight of car engine -- would survive
contact with the atmosphere.
The Gravity
Ocean Circulation Explorer (GOCE) satellite was placed in orbit in 2009 on a
mission to monitor variations in gravity and sea levels.
The sleek,
finned craft's mission came to a natural end when it ran out of fuel on October
21, leaving it without power to maintain its altitude in low orbit, where there
are still lingering molecules of air.
GOCE was
launched in March 2009 at an altitude of 260 kilometres (160 miles) -- later
lowered to 224 km -- the lowest ever for a research satellite.
The
350-million-euro ($465-million) mission has lasted twice as long as its
initially-scheduled 20 months.
ESA said
the satellite reentered the atmosphere around midnight GMT Sunday on a
descending orbit that crossed Siberia, the western Pacific Ocean, the eastern
Indian Ocean and Antarctica.
GOCE was
designed and built before 2008, when international recommendations were adopted
that a scientific satellite must be able to execute a controlled reentry, or
burn up completely after its mission.
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