Satellite landed, exact location not yet known

A decommissioned Nasa satellite, the biggest piece of US space junk to fall in 30 years, has crash-landed but the precise location is not yet known, the US space agency said early yesterday.

If debris fell on land (and that’s still a BIG if), Canada is the most likely area- Nasa on Twitter

Nasa has repeatedly said there is only a “very remote” risk to the public from the 26 fragments of the Upper Atmosphere Research Satellite (UARS) which were expected to survive the fiery re-entry into the atmosphere.

The satellite fell back to Earth between 5.23 and 7.09 a.m. yesterday, but the precise re-entry time and location “are not yet known with certainty,” Nasa said.

“The Joint Space Operations Centre at Vandenberg Air Force Base in California said the satellite penetrated the atmosphere over the Pacific Ocean,” it said, noting the landing site was still unconfirmed.

On its Twitter feed, Nasa said, “If debris fell on land (and that’s still a BIG if), Canada is the most likely area.”

The two dozen parts of the UARS that may have survived re-entry could weigh anything from one to 158 kg, the space agency said, and the debris field is expected to span 800 km.

Earlier, Canada, Africa and Australia had all been named as possible sites for touchdown of debris from the tour-bus-sized UARS.

The tumbling motion of the satellite has made it difficult to narrow down the location. Given that the world is 70 per cent water, an ocean landing was considered likely.

“In the entire 50-plus year history of the space programme, 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.”

Last Friday, a Nasa spokeswoman said the US Department of Defence and the space agency were busy tracking the debris and keeping all federal disaster agencies informed.

The Federal Aviation Administration issued a notice last Thursday to pilots and flight crews of the potential hazard, and urged them to report any falling space debris and take note of its position and time.

Last Friday, Italy’s civil protection agency warned that the probability of a crash in its northern territory had risen from 0.6 to 1.5 per cent, and urged residents to stay indoors, on lower floors, preferably near load-bearing walls.

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-tonne Skylab crashed into western Australia in 1979.

The surviving chunks of the 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”.