AP Photo

The BBC's Andy Moore says where debris came down is "a bit of a mystery"

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 well out into the North Pacific.