NASA is not aware of any possible debris sightings from this geographic area. This is your source for official information on the re-entry of UARS. All information posted here has been verified with a government or law enforcement agency. Six years after the end of its productive scientific life, UARS broke into pieces during re-entry, and most of it up burned in the atmosphere.
Twenty-six satellite components, weighing a total of about 1, pounds, could have survived the fiery re-entry and reach the surface of Earth. I think you have an error there. Lower solar activity means lower atmospheric density at high altitudes, which means lower drag, which means lower descent rate.
Higher solar activity would speed descent rate. Luminance was varying rapidly, which is why I noticed it. Skip to content. Nasa satellite hurtling to Earth. How to fall to Earth. This video can not be played To play this video you need to enable JavaScript in your browser. UARS orbited the Earth between 57 degrees North and South Nasa calculated some 26 components might survive the fall to Earth The largest was a moveable instrument platform weighing almost kg In total, about half a tonne could have made it all the way to the surface The risk of any one of 7bn people being hit was 1 in 3,, Nasa says.
Published 24 September Published 23 September Published 22 September NASA now has no control over when the satellite enters the atmosphere. All it can do right now is predict which pieces will fall in what order, based on their size and mass. Heavier objects for a given area will move faster and thus fall farther downrange than lighter ones.
NASA expects the grapple-fixture abutment plate to hit the ground first, a little more than miles downrange from the point that the satellite enters the atmosphere, followed by a bracket, the propellant tanks, the grapple extension, a stainless steel reaction-wheel rim, and finally the forward bulkhead fitting.
The total debris trail will stretch about miles. But where will this mile path fall? Even now, a day or two before entry, no one can precisely predict it. UARS is in an orbit inclined at 57 degrees, which means that once every hour and a half or so, its ground trace the point on the ground directly below it will change in latitude from 57 degrees north to 57 degrees south.
It could hit anywhere in that latitude band, and there's no way to predict where until you know the precise time of entry, when it falls deeply enough into the atmosphere that it can no longer maintain orbital velocity. Even then, it's still difficult to predict the path because it depends upon chaotic, unpredictable fluctuations in the atmosphere.
For example, the speed with which the orbit decays depends on the density of the upper atmosphere, which can vary even from hour to hour as the earth turns and is heated by a variable sun. Finally, the satellite is tumbling end over end, so even if the atmosphere were predictable, it would be an enormous task for NASA to model the satellite's path.
Even a couple hours before the event, the Joint Space Operations Center JSpOC, formerly known as NORAD will be able to predict the location only to within a few minutes and a few thousand miles—about a quarter of the way around the planet. It's worth noting, however, that NASA can constrain the possible paths somewhat to rule out areas.
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