Scientists are monitoring a defunct Chinese space station
that is expected to fall to Earth around the end of the month, the largest
manmade object to re-enter Earth’s atmosphere in a decade.
The head of the European Space Agency’s debris office,
Holger Krag, says China’s Tiangong-1 space station will likely fall to Earth
between March 30 and April 3.
Krag said it still not yet known where the space station
will hit Earth, but said it would be extremely unlikely for anyone to be
injured when it does.
Injury unlikely
“Our experience is that for such large objects typically
between 20 and 40 percent of the original mass, of 8.5 tons, will survive
re-entry and then could be found on the ground, theoretically,” he said.
“However, to be injured by one of these fragments is
extremely unlikely. My estimate is that the probability to be injured by one of
these fragments is similar to the probability of being hit by lightning twice
in the same year,” Krag added.
He said the space station is expected to fall between the
areas of 43 degrees south and 43 degrees north, and everything outside that
zone is considered safe.
“Northern Europe including France, Germany, Austria and
Switzerland are definitely on the safe side. Southern Europe, the southern part
of North America, South Asia, Africa, Australia and also South America are
still within the zone today,” he said.
Where will it hit?
Scientists say it is hard to predict where Tiangong-1 will
hit Earth in part because of its low orbit and high velocity. They say the
space station is traveling 17,400 mph and orbits Earth about every 90 minutes.
Tiangong-1 was launched into orbit in 2011 as China’s first
space lab. It carried out orbit experiments in preparation for China’s plan to
put a permanent space station into orbit by 2023.
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