A defunct satellite entered the atmosphere early Sunday and pieces of
it were expected to crash into the earth, theGerman Aerospace Center
said.
There was no immediate solid evidence to determine above which
continent or country the ROSAT scientific research satellite entered
the atmosphere, agency spokesman Andreas Schuetz said.
Most parts of the minivan-sized satellite were expected to burn up
during re-entry, but up to 30 fragments weighing 1.87 tons (1.7 metric
tons) could crash into Earth at speeds up to 280 mph (450 kph).
Scientists were no longer able to communicate with the dead satellite
and it must have traveled about 12,500 miles (20,000 kilometers) in
the last 30 minutes before entering the atmosphere,Schuetz said.
Experts were waiting for "observations from around the world," he added.
Scientists said hours before the re-entry into the atmosphere that the
satellite was not expected to hit over Europe, Africa or Australia.
According to a precalculated path it could have been above Asia,
possibly China, at the time of its re-entry, but Schuetz said he could
not confirm whether the satellite actually entered above that area.
The 2.69-ton (2.4 metric ton) scientific ROSAT satellite was launched
in 1990 and retired in 1999 after being used for research on black
holes and neutron stars and performing the first all-sky survey of
X-ray sources with an imaging telescope.
The largest single fragment of ROSAT that could hit into the earth is
the telescope's heat-resistant mirror.
During its mission, the satellite orbited about 370 miles (600
kilometers) above the Earth's surface, but since its decommissioning
it has lost altitude, circling at a distance of only 205 miles (330
kilometers) above ground in June for example, the agency said.
Even in the last days, the satellite still circled the planet every 90
minutes, making it hard to predict where on Earth it would eventually
come down.
A dead NASA satellite fell into the southern Pacific Ocean last month,
causing no damage, despite fears it would hit a populated area and
cause damage or kill people.
Experts believe about two dozen metal pieces from the bus-sized
satellite fell over a 500-mile (800 kilometer) span of uninhabited
portion of the world.
The NASA climate research satellite entered Earth's atmosphere
generally above American Samoa. But falling debris as it broke apart
did not start hitting the water for another 300 miles (480 kilometers)
to the northeast, southwest of Christmas Island.
Earlier, scientists had said it was possible some pieces could have
reached northwestern Canada.
The German space agency puts the odds of somebody somewhere on Earth
being hurt by its satellite at 1-in-2,000 — a slightly higher level of
risk than was calculated for the NASA satellite. But any one
individual's odds of being struck are 1-in-14 trillion, given there
are 7 billion people on the planet.
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Online:
The German space agency on ROSAT: http://bit.ly/papMAA
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