NASA confirms satellite re-entry, debris believed to have fallen in Canada

NASA this morning confirmed the re-entry into Earth atmosphere of the biggest piece of US space junk to fall in 30 years. Most of the debris is believed to have crashed into the sea, but some bits may have crashed in remote parts of Canada. 

The two dozen parts that survive the re-entry may weigh as little as two pounds (one kilogram) or as much as 350 pounds (158 kilograms), NASA said, and the debris field is expected to span 500 miles (800 kilometres).

The tumbling motion of the satellite had made it difficult to narrow down the crash location. 

"In the entire 50 plus year history of the space program, no person has ever been injured by a piece of re-entering space debris," said Mark Matney, an orbital debris scientist at NASA.

"Keep in mind we have bits of debris re-entering the atmosphere every single day." 

Orbital debris experts say space junk of this size from broken-down satellites and spent rockets tends to fall back to Earth about once a year, though this is the biggest NASA satellite to fall in three decades.

NASA's 85-ton Skylab crashed into western Australia in 1979.

The surviving chunks of the tour-bus-sized UARS, which launched in 1991 and was decommissioned in 2005, will likely include titanium fuel tanks, beryllium housing and stainless steel batteries and wheel rims.

"No consideration ever was given to shooting it down," NASA spokeswoman Beth Dickey said.

The craft contains no fuel and so is not expected to explode on impact, and NASA also said on Twitter that talk of "flaming space debris" was a "myth."

"Pieces of UARS landing on Earth will not be very hot. Heating stops 20 miles up, cools after that," NASA said, adding that UARS contains nothing radioactive but its metal fragments could be sharp.

The US space agency has warned anyone who comes across what they believe may be UARS debris not to touch it but to contact authorities for assistance.

Space law professor Frans von der Dunk from the University of Nebraska-Lincoln told AFP that the United States will likely have to pay damages to any country where the debris falls.

"The damage to be compensated is essentially without limit," von der Dunk said, referring to the 1972 Liability Convention to which the United States is one of 80 state signatories.