20 September 2011
A satellite is falling to Earth this week, and you can indirectly blame your local weathercaster for it. What`s more, this forecast will actually come true!
All kidding aside, NASA`s UARS (Upper Atmosphere Research Satellite) is expected to make landfall (or better yet, ocean-fall) between September 22nd and 24th, after two decades in space.
UARS is a satellite that NASA, environmental scientists, and meteorologists developed and used to study the Earth`s upper atmosphere, particularly the ozone layer. The 13,000 lb. satellite was deployed in 1991 from the Space Shuttle Discovery with an expected life of just 3 years. But UARS was the little satellite that could, and kept on running - with six out of 10 instruments still working as of 2005. It was decommissioned later that year and in December 2005, it was sent into a lower orbit to slowly burn itself up in a sort of satellite suicide.
It is expected to take its last gasp this week as it makes an uncontrolled entry into the Earth`s lower atmosphere, plummeting toward Earth and breaking up into around 100 pieces. It`s estimated that about two dozen of those pieces will be big enough to survive burning up in the atmosphere and make it to the Earth`s surface in a linear debris field of about 500 miles. As for where on Earth it may hit, NASA says that, as of now, anywhere from 57 degrees N. latitude to 57 degrees S. latitude will be the expected touchdown. That means people in northern Canada, Greenland, northern Europe and northern Asia can breathe a sigh of relief, but everyone else... well, you`re fair game.
Ok, so really, what are the odds of being hit by a piece of it? Well according to NASA, it`s very small. There is a 1 in 3,200 chance that a person somewhere in the world will be struck, a world in which about 7 billion people live. Keeping in mind that 75 percent of the Earth`s surface is also covered by water, the chances seem even more remote. NASA`s Chief Scientist for Orbital Debris, Nicholas Johnson, said that used satellites, rockets, and other space debris fall to Earth frequently, and in more than 50 years of the Space Age, no one has ever been hurt. Here`s the catch though: NASA says there`s a significant fudge factor to where it will land, with a margin of error around 5,000 miles. That`s like telling every person from Paris to Beijing to, "Duck!"
More than likely, what you will get could be a bit of a celestial show. As the pieces of the satellite burn up, some will be large enough to create fireballs that should be visible even in the daytime. Fortunately NASA will refine its timing and location of the landing over the next few days. The agency does want to remind people that if any debris does hit land, and you happen to discover it, do not touch it. Instead, they say, call your local law enforcement agency and tell them of your finding. Let`s hope this satellite is destined to sleep with the fishes!
Source: The Washington Post.