NASA provided a final update on when and where the decommissioned Upper Atmosphere Research Satellite (UARS) fell to Earth, and said it ended up falling in one of the most remote, watery places on Earth – a perfect spot for not causing damage or fatalities. The U.S. Air Force calculations put the 6-ton satellite’s death dive into an area in the Pacific Ocean, around the Christmas Islands, at 0400 GMT on September 24, 2011. Because the re-entry took place over this remote area, it’s likely that no one saw it and NASA has not gotten any credible reports from any eyewitnesses. And so the only way to determine exact information about the satellite’s location is when data about it no longer became available.
“There are discreet sensors in the US space surveillance network placed around the world, and one of the ways we determine whether a satellite has re-entered is by looking at sensors who have failed to detect a satellite that is predicted to come by,” said Nicholas Johnson, NASA’s chief scientist for orbital debris. “And so we look at sensors in the network soon after 0400 GMT time and found that no sensors in the US Space Surveillance network was able to observe the satellite after that time.”
The Joint Space Operations Center at Vandenberg Air Force Base in California determined the satellite entered the atmosphere over the Pacific Ocean at 14.1 degrees south latitude and 189.8 degrees east longitude (170.2 west longitude). The satellite broke apart and continued falling and traveling for another 300 miles to the northeast, with about 26 larger metal parts from the bus-sized satellite falling over a 500-mile span.
Another satellite will make an uncontrolled plunge back to Earth in late October or early in November. The German ROSAT astronomy satellite weighs less than 2.5 tons, but experts says more pieces could survive re-entry than the UARS satellite.
The German space agency puts the odds of anyone anywhere on Earth being hurt by its satellite at 1-in-2,000, slightly highter than the 1-in-3,200 odds for UARS. But given there are 7 billion people on Earth, any one person’s odds of being struck are 1-in-14 trillion.
Source: NASA
