Just days after NASA's Upper Atmosphere Research Satellite plunged into the Pacific Ocean, another satellite -- this one German -- is beginning its descent to Earth. And once again, nobody knows where it will land.
The crash isn't imminent -- the German space agency is predicting it will reenter the Earth's atmosphere in late October or early November -- but the announcement is sure to provoke a rush of speculation about whether it will hit land or, in a worst case scenario, a person.
The chances of anyone being hurt by the satellite are very small, because most of the Earth's surface is uninhabited, but anything is possible. The German space agency said the odds of somebody on Earth being hit by the satellite are one in 2,000 -- higher than the estimated risk for UARS, but still tiny -- and the odds of any one individual being hit are an infinitesimal one in 14 trillion.
The Rontgensatellit, or ROSAT, weighs about two and a half tons. That's somewhat lighter than UARS, but more pieces are expected to survive re-entry into the atmosphere. Thirty pieces, possibly including shards of glass from the satellite's mirrors, are expected to hit Earth.
It is impossible to predict with any degree of certainty where the satellite will land, or even what hemisphere of the Earth it will hit. A difference of just a few minutes in landing time can mean the difference between Seattle and Samoa. But that won't stop people from trying to guess or bet on it.
ROSAT was launched in 1990 and died in 1998. Because it has no fuel left, there is no way to control its path. The situation was the same with UARS.
A multi-ton satellite plunging, uncontrolled, to Earth is a scary prospect, but the danger is minimal. And even better news is that NASA does not expect any more of its large satellites to fall uncontrolled in the next 25 years, according to CBS News.