November 3, 2008

ISS Castoff Re-Enters Atmosphere

NASA officials reported that a refrigerator-size ammonia tank thrown overboard from the International Space Station over a year ago finally fell back to Earth late Sunday.

Spacewalker Clay Anderson discarded the 1,400-pound ammonia servicer from the orbiting outpost on July 23, 2007 to clear the way for future assembly work.

The fridge's re-entry into Earth's atmosphere occurred around 11:51 p.m. EST over the ocean south of Tasmania, according to tracking reports.

Station program manager Mike Suffredini said the ground track was on an ascending node, therefore whatever debris may have been still together after re-entry fell in the ocean between Australia and New Zealand.

Suffredini said there was a very low likelihood that anybody would be impacted by it.

The discarded ammonia tank was originally to be sent down on a space shuttle, NASA said, but plans changed and officials opted to toss it away instead.

Anderson flung the hefty three-quarter-ton unit off the end of the space station's robot arm along with an old camera mounting also deemed no longer necessary.

The tank gradually slowed down due to the friction exerted by the extreme upper atmosphere, thus descending and becoming subject to more friction and so on.

NASA launched the ammonia tank in 2001 to provide additional coolant in case of a leak in an interim thermal control system that supported the initial stages of station assembly. The ammonia was never needed and the lab's permanent cooling system is now in operation.


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