As you know, the UARS (Satellite) is in the process of de-orbiting. It is a bit more like a death watch (have you ever done one of those?) than a technological procedure. The satellite was pushed into a dangerous orbit that would drag it down within several days, and it is now losing its grip on orbital inertia as it plows ungracefully through thicker and thicker regions of the upper atmosphere. One wonders what might affect UARS’s orbit. Would a powerful weather front with tall thunderheads, or a hurricane cause enough extra molecules of air to be pushed up a bit farther, to cause the satellite to slow slightly as it plummet through a bump in the atmosphere? Does it take a hit whenever it passes over the Tibetan Plateaux? Is there enough of a difference in friction on the sunny vs shady side of the earth to matter? What about lunar tidal forces, will they start to count? I know nothing of these things so this is all conjecture. For all I know there are Leprechauns riding on the damn thing that at some point will tip it over and make it fall to Earth.
In any event, NASA does have a software model to calculate the likely time of death of UARS, and the time equals, in turn, the location of where whatever debris is left of the trolley-sized space-machine hits the planet. And this morning, NASA has put out a new estimate.
UARS will likely re-enter tomorrow, September 23rd, during the afternoon, US Eastern Daylight Time. It will NOT be passing over North America during that time. Remember that the field of debris is expected to be quite long and narrow.
What this means is that you should keep an eye on Twitter. The hashtag is #UARS. The moment you start to see tweets of fireworks or debris, plot it on a map. Two points is all you’ll need to predict the downstream end of the debris field.
You should have a pair of gloves and several different size bags ready, as well as some stick-on labels, a Magic Marker, and a notebook and pencil to label the bits and take notes on where you found them.
Good luck, Astro-litter-bugs!
[Photo from Wikipedia]