Satellite crashes without a trace, and Nasa doesn’t even know where

The satellite, which was the size of a bus, plunged to earth at about 5am yesterday morning, but by last night, Nasa’s experts were forced to admit that they still didn’t know where it had hit, or if any part of it had survived its fiery descent.

The space agency reported that it first penetrated the earth’s atmosphere “somewhere over the Pacific Ocean”, but that this did not necessarily mean that all of it fell into the sea.

Because the plummet to Earth began over the ocean, and given the lack of any reports of people being hit, that “gives us a good feeling that no one was hurt,” Nasa spokesman Steve Cole said. However, he added, officials “didn’t know for certain”.

Speculation ran riot on the internet and on social networking site Twitter, much of it focusing on unconfirmed reports and even video of debris in Alberta, Canada.

Cole said the reports would be true, because the last known tracking of the satellite’s path included Canada, starting north of Seattle in the US and then in a large arc north then south. From there, the track continued through the Atlantic south toward Africa. But it was unlikely the satellite got that far if it started falling over the Pacific, he added.

About 26 pieces of the satellite – representing 1,200 pounds of heavy metal – had been expected to rain down. Although the biggest surviving chunk could have weighed around 300 pounds, much of it was expected to have burned up on re-entry. Any one person’s odds of being struck by this satellite were estimated at one in 22 trillion, given there are seven billion people on the planet.

Cole said Nasa was hoping for more details from the US Air Force, which was responsible for tracking debris.

But given where the satellite may have fallen, officials may never quite know precisely.

“Most space debris is in the ocean. It’ll be hard to confirm,” Cole said.

The satellite, known as the Upper Atmosphere Research Satellite, ran out of fuel and ceased operating in 2005, cutting its life short by two decades. It has been slowly losing altitude ever since, pulled by the planet’s gravity.

It was launched aboard space shuttle Discovery in 1991, before Nasa and other nations started new programmes that prevent this type of uncontrolled satellite crash.

The 13,000-pound satellite was sent into orbit to study ozone and other chemicals in the Earth’s atmosphere.

At 35 feet long and 15 feet in diameter, it is the biggest Nasa spacecraft to crash back to Earth, uncontrolled, since the post-Apollo 75-ton Skylab space station and the more than 10-ton Pegasus 2 satellite, both in 1979.

Bits of space junk re-enter the atmosphere virtually every day. No injuries have ever been reported.

Russia’s 135-ton Mir space station slammed through the atmosphere in 2001, but it was a controlled dive into the Pacific.