UARS is scheduled to de-orbit Friday, plus or minus every day, according to NASA scientists' calculations.
NASA scientist Mark Matney says UARS is most likely to de-orbit Friday morning. "Right now, UARS is truly re-entering a little quicker than anticipated because solar activity is now up, which speeds re-entry," he stated.
This is the greatest NASA satellite another to Earth uncontrolled because Skylab in 1979. UARS weighs about 6 tons and will be the size a school bus, but most of it's going to burn on re-entry. It is what's going to survive re-entry that worries NASA.
Nicholas Johnson, NASA's chief orbital debris scientist, says their analysis reveals that 26 parts of UARS can survive. "These 26 components, which we anticipate will survive all the way down, will probably be going in a moderate velocity of tens to many miles an hour," he stated. "All these 26 happen to be identified as potentially causing damage as long as they hit a structure or a individual though the likelihood of which can be very, quite, low."
Johnson stated any one person's probabilities of getting hit by debris are tiny -- one thing like One out of 21 trillion. The probabilities that relating to the 7 billion people that is known, one advisors, somewhere, might be hit -- those likelihood is far more like One inch 3,200.
About 150 a great deal of meteorites, in pieces big and small, land in the world daily. Some are visible, like the meteor spotted over California the other day, but a lot of the debris is small it is by no means identified.
The thing that makes UARS so remarkable is its size and also the advance warning from NASA officials that it is coming. Since of the varying density with the upper atmosphere, they won't be able to tell where it is intending to land until two hours just before it plunges back to Earth.
Johnson says the possible target location is wide. "It's a pretty wide region, 57 degrees north to 57 degrees south," he said.
That "pretty significantly encompasses the entire populated world. I mean, there's a small percent that reside above and below those latitudes, even so the the vast majority of the 7 billion men and women on earth live inside those latitudes," he stated.
That indicates pretty significantly anyone south on the Arctic and north of Antarctica. Johnson says guilty sunlight for mystery. "The sun is constantly changing the output of power, which affects the atmosphere, and that may accelerate of delay the re-entry of your satellite," he said.
UARS (Upper Atmosphere Study Satellite) premiered by way of the space shuttle Discovery in 1991. UARS was NASA's initial multi-instrumented satellite to analyze the chemistry of Earth's atmosphere and look at the quantity of light that comes with the sun at ultraviolet and visible wavelengths. UARS stopped becoming productive in 2005.
When UARS launched, it orbited the earth in an altitude of 350 miles. It is now right down to 140 miles, and definately will keep lose altitude until there's sufficient air around it to slow it from orbital speeds.
U.S. Space Command at Vandenberg AFB is going to be tracking UARS the way it returns and NASA will post normal updates.
source:http://abcnews.go.com
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