UARS Resting Place Unknown, But No One Got Hurt

UARS Resting Place Unknown, But No One Got Hurt

NASA does not know — and may never know — exactly where debris from the Upper Atmosphere Research Satellite (UARS) landed.

That was the message from NASA’s orbital debris expert, Nicholas Johnson, during a media teleconference this afternoon.

NASA has posted a map of the ground track for UARS’s final orbit. The vast majority of its final journey was over the ocean. NASA and Department of Defense specialists at the Joint Space Operations Center (JSPoC) estimate that the satellite reentered at 04:16 GMT (12:16 am EDT), although that is not known for certain. If that is correct, UARS would have been in the part of the ground track off the west coast of North America going up and over parts of Canada. Johnson said that if the satellite had survived that part of the trip, observers in the U.S. Pacific Northwest and Canada would have seen it, and there were no sightings. The nominal reentry point is shown on the map as a circle with a dot in the middle over the Pacific Ocean.

Essentially, if there was no one to see it, and it was out of range of the sensors that were tracking it, there is no way to know where the pieces fell. Johnson said that NASA is open to hearing from people — perhaps passengers on airlines flying over the Pacific at that time — who may have seen something, but otherwise, it will remain a mystery.

Johnson stressed that satellite or orbital debris reentries occur every day, and there are significantly sized pieces that come down each week. Something the size of UARS comes down about once a year. Unless there is some reason to do so, analysts do not bother to go back and try to determine the exact reentry times or places. In fact, he said, the usual procedure is for the North American Aerospace Defense Command (NORAD) to look for the object on three passes and if it is not located, they assume that it reentered.

NASA has not received any reports of injuries or debris being found. Johnson said that NASA routinely is contacted by individuals who believe they have found a piece of space debris and NASA checks out every one. Few actually are reentered space objects, he added, but if someone believes they have found a piece of UARS debris, they are welcome to contact the space agency (though NASA warns that the object should not be touched since it may be sharp). When asked if NASA wants the pieces returned, Johnson said that under existing agreements the pieces must be returned to NASA if requested, but NASA must pay the transportation costs and often does not request their return.

Twelve countries work together through the Inter-Agency Space Debris Coordinating Committee (IADC) to track and monitor reentries of space objects. Ten of the 12 participated in tracking the UARS reentry, Johnson said. Each has its own method of calculating expected reentry times, and over a decade of working together, they have found that one way is not clearly bettter than the others. All of the participants calculated about the same reentry time of 04:16 GMT, giving more credence to that as the most likely time.

An audiocast of the media briefing is available for one week by calling toll free in the United States: 866-516-0666.

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