A piece of
space trash the size of a refrigerator plunged into the Earth's atmosphere late
Sunday to burn up over the southern Pacific Ocean, more than a year after an
astronaut tossed it off the International Space Station, NASA officials said
today.
Space
station program manager Mike Suffredini told reporters the orbital
trash, a 1,400-pound (635-kg) tank
of toxic ammonia coolant, slammed into the Earth's atmosphere at an
altitude of about 50 miles (80 km) as it flew above the ocean just south of Tasmania.
"What
debris may have been still together after re-entry, it fell into the ocean
between Australia and New Zealand," Suffredini said during a NASA briefing. "I
know a lot of folks were wondering what the end result of that was."
NASA
expected up to 15 pieces of the tank to survive the fiery plunge, ranging in
size from about 1.4 ounces (40 grams) to nearly 40 pounds (17.5 kg). The largest
pieces, if they survived, may have hit the ocean at speeds of up to 100 mph
(164 kph).
The U.S.
Space Surveillance Network kept a close watch on the ammonia tank for NASA as
part of its ongoing effort to monitor the thousands of pieces
of orbital debris circling Earth.
Known as an
Early Ammonia Servicer (EAS), the coolant tank was the largest piece of trash
ever disposed of by hand from the space station. NASA astronaut Clayton
Anderson junked the tank while wearing a spacesuit and standing at the tip of
the station's Canadian-built robotic arm during a July 23, 2007 spacewalk.
"We're
really fortunate to be able to track objects to a fairly small size,"
Suffredini told SPACE.com before the ammonia tank re-entered, adding
that the ammonia tank was rather large and easy to track.
NASA takes
great care to ensure that any trash
tossed overboard from the space station does not endanger other spacecraft
or people on Earth, he added.
The
obsolete tank had served as a spare reservoir of ammonia coolant for the space
station in case of leaks since 2001, but was no longer required after
astronauts activated the outpost's main cooling system in early 2007. But
because the tank was so old, engineers were worried its structural integrity
wouldn't hold during a return to Earth aboard a NASA shuttle.
Instead
they asked Anderson to toss it during a spacewalk dedicated to discarding old
equipment. He also jettisoned a 212-pound (96-kilogram) video camera stand, but
that item burned up in Earth's atmosphere earlier this year.
"I just
like it when they've re-entered and it's not a problem," Suffredini said.
"One of the big concerns for any orbiting pressurized spacecraft is
orbital debris."
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