A piece of space station trash the size of a refrigerator plunged through the Earth's atmosphere late Sunday over the Indian Ocean, South of Tasmania, more than a year after an astronaut tossed it overboard.
NASA and the U.S. Space Surveillance Network tracked the object — a 1,400-pound (635-kilogram) tank of toxic ammonia coolant thrown from the international space station — to make sure it does not endanger people on Earth.
"This has got a very low likelihood that anybody will be impacted by
it," said Mike Suffredini, NASA's space station program manager, in an
interview over the weekend. "But still, it is a large object and pieces will enter and
we just need to be cautious."
NASA astronaut Clayton Anderson threw the ammonia tank from the tip of the space station's Canadian-built robotic arm during a July 23, 2007, spacewalk. He tossed away an unneeded video camera stand overboard as well, but that 212-pound (96-kilogram) item burned up harmlessly in the atmosphere early this year, Suffredini said.
NASA expects up to 15 pieces of the tank to survive the searing hot temperatures of re-entry, ranging in size from about 1.4 ounces (40 grams) to nearly 40 pounds (17.5 kilograms).
If they reach all the way to land, the largest pieces could slam into the Earth's surface at about 100 mph (161 kilometers per hour). But a splashdown at sea was also possible, as the planet is two-thirds ocean.
NASA's announcement follows less that a year after it said that it had little choice but to jettison two pieces of large junk hardware, including the 1,400-pound container filled with ammonia coolant, from the International Space Station.
"It sounds bad," said Kirk Shireman, who chair's NASA space station mission management team. "We agonized over this for a very long time before we came to this decision."
The space agency has shunned the practice of throwing trash from the station into free space. But said in this instance, they were making an exception.
The brace, which restrained larger communications antenna during an earlier shuttle launch, was no longer needed and taking up needed space.
They say that the coolant tank could not be returned to Earth on a shuttle, because there will be no room on the next 14 remaining shuttle station assembly flights. Since the ammonia container has “surpassed its structural design life”, NASA says junking it was their best option.
Both objects are tracked by military radar so NASA can take any evasive measures with the station and future shuttle missions or warn the operators of other satellites of a potential collision.
The ammonia container circled Earth for at least 300 days before it plummeted on Sunday through the atmosphere.
Shireman was right—that doesn’t sound good practice going forward with future junk deliveries to the galactic junkyard.
Posted by Rebecca Sato with Casey Kazan.