NASA’s 6-tonne satellite re-enters earth off US west coast

NASA has announced that its defunct six-tonne satellite plummeted through Earth’s atmosphere over the Pacific Ocean, off the US west coast on early Saturday morning.

It appears likely the decommissioned craft came down between 03:23 and 05:09 GMT - with a best estimate of 04:16.

If correct, this means any debris that survived to the surface probably went into water and not on land.

The Upper Atmosphere Research Satellite (UARS) is the largest American space agency satellite to return uncontrolled into the atmosphere in about 30 years.

The fall to Earth was monitored by the Joint Space Operations Center (JSPOC) at Vandenberg Air Force Base in California.

Its best estimate for the timing of the re-entry would have seen UARS come in at a point located at 31 degrees North latitude and 219 degrees East longitude - well out into the North Pacific.

However, if UARS re-entered many minutes after 04:16, it is possible debris could have reached the American landmass.

There were some unconfirmed reports of glowing wreckage moving across the sky in western Canada, but NASA said it had yet to receive credible evidence that this was so, less still that any debris items had been found.

Most of the 20-year-old satellite should simply have burnt up on re-entry into the Earth’s atmosphere, but modelling work indicated perhaps 500kg could have survived to the surface.

UARS was deployed in 1991 from the space shuttle Discovery on a mission to study the Earth’s upper atmosphere.