Update: Dead Satellite Crashes on Earth
 

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Updated 8:24 p.m.EDT, Fri September 23, 2011


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Miami (CNN) -- A satellite on the verge of falling back to Earth appears to have begun slowing down but will not re-enter the atmosphere until late Friday or early Saturday U.S. time, according to NASA.
The United States is once again an unlikely but potential target for the 26 pieces of the Upper Atmosphere Research Satellite, expected to survive the descent. Those pieces, made of stainless steel, titanium and beryllium that won't burn, will range from about 10 pounds to hundreds of pounds, according to NASA.
NASA said Friday morning that it would be hours before it would be able to zero in on the time and place of the re-entry.
Mark Matney of NASA's Orbital Debris team in Houston said there's no way to know exactly where the pieces will come down.
"Keep in mind, they won't be traveling at those high orbital velocities. As they hit the air, they tend to slow down. ... They're still traveling fast, a few tens to hundreds of miles per hour, but no longer those tremendous orbital velocities," he explained.
Because the satellite travels thousands of miles in a matter of minutes as it orbits -- even just before it begins re-entry -- it will be impossible to pinpoint the exact location the pieces will come down. On top of that, Matney said, the satellite is not stable.
"Part of the problem is, the spacecraft is tumbling in unpredictable ways, and it is very difficult to very precisely pinpoint where it's coming down even right before the re-entry."
Because water covers 70% of the Earth's surface, NASA has said that most if not all of the surviving debris will land in water. Even if pieces strike dry land, there's very little risk any of it will hit people.
However, in an abundance of caution, the Federal Aviation Administration on Thursday released an advisory warning pilots about the falling satellite, calling it a potential hazard.
"It is critical that all pilots/flight crew members report any observed falling space debris to the appropriate (air traffic control) facility and include position, altitude, time and direction of debris observed," the FAA statement said.
The FAA said warnings of this sort typically are sent out to pilots concerning specific hazards they may encounter during flights such as air shows, rocket launches, kites and inoperable radio navigational aids.
NASA says space debris the size of the satellite's components re-enters the atmosphere about once year. Harvard University astrophysicist Jonathan McDowell noted that the satellite is far from being the biggest space junk to come back.
"This is nothing like the old Skylab scare of the '70s, when you had a 70-ton space station crashing out of the sky. So, I agree with the folks in Houston. It's nothing to be worried about," McDowell said.
Pieces of Skylab came down in western Australia in 1979.
The only wild card McDowell sees is if somehow a chunk hits a populated area.
"If the thing happens to come down in a city, that would be bad. The chances of it causing extensive damage or injuring someone are much higher."
NASA said that once the debris hits the atmosphere 50 miles up, it will take only a matter of minutes before the surviving pieces hit the Earth.

re: Update: Dead Satellite Crashes on Earth
 

Update: Satellite Has Landed Somewhere On Earth.


By the CNN Wire Staff
updated 9:03 AM EST, Sat September 24, 2011

Miami (CNN) -- Pieces of a defunct satellite that plummeted to Earth have settled, NASA said Saturday morning
The space agency said the Upper Atmosphere Research Satellite "is down," according to the space agency's Twitter page. NASA said debris fell to Earth between 11:23 p.m. ET Friday and 1:09 a.m. ET Saturday, but it was not immediately clear where the pieces may have landed.
NASA said the satellite pierced through the atmosphere over the Pacific Ocean, but the exact time and location were not known.
About two dozen pieces of the satellite were expected to survive the crash through the Earth's atmosphere.
Late Friday night, NASA predicted satellite parts would pass "over Canada and Africa, as well as vast areas of the Pacific, Atlantic and Indian oceans."
"The risk to public safety is very remote," NASA said.
The 26 pieces expected to survive the descent -- made of stainless steel, titanium and beryllium that won't burn -- ranged from about 10 pounds to hundreds of pounds, according to NASA.
"The U.S. is very safe from (the satellite) ... It's final orbit did not cross the United States," the space agency tweeted early Saturday.
But reports of suspected sightings emerged from San Antonio, Texas, where a TV photographer caught images of bright objects darting rapidly in the night sky, and from Hawaii, where Robert Jeffcoat saw what he believed were two chunks from the satellite.
Jeffcoat was running errands when the first flying object left a thick, white trail that lingered in the sky for about 20 minutes, he said. A second object followed the same path and was "massive," he said.
"It's was like a comet, but smoke," he said. "I'm guessing it landed in the ocean, the way it was going."
Mark Matney of NASA's Orbital Debris team in Houston said before spacial rubbish fell that there was no way to know exactly where the pieces would come down.
"Part of the problem is, the spacecraft is tumbling in unpredictable ways, and it is very difficult to very precisely pinpoint where it's coming down even right before the re-entry," Matney said.
The Federal Aviation Administration released an advisory Thursday warning pilots about the falling satellite, calling it a potential hazard.
"It is critical that all pilots/flight crew members report any observed falling space debris to the appropriate (air traffic control) facility and include position, altitude, time and direction of debris observed," the FAA statement said.
The FAA said warnings of this sort typically are sent out to pilots concerning specific hazards they may encounter during flights such as air shows, rocket launches, kites and inoperable radio navigational aids.
NASA said space debris the size of the satellite's components re-enters the atmosphere about once a year. Harvard University astrophysicist Jonathan McDowell noted that the satellite is far from being the biggest space junk to come back.
"This is nothing like the old Skylab scare of the '70s, when you had a 70-ton space station crashing out of the sky," McDowell said.
Pieces of Skylab came down in western Australia in 1979.
Jeffcoat said he was amazed his home of Paia, Maui, seemed to be an ideal place to watch hunks of a satellite rain from the sky.
"Off all the places in the world where it could hit, here it was, in Maui," he said. "It was quite weird."