Watch out for falling satellitesWith no one at the wheel, should we be worried about the large US spy satellite now headed for a crash landing?US spy satellite 193 is predicted to de-orbit less than gracefully in Feburary or early March. The chances of it actually hitting a populated area are exceedingly small, but perhaps you can catch a few micrograms of it using Kiteman's How to catch a star Instructable.What is happening?An out-of-control US spy satellite will crash to Earth in the coming months, government officials say. The satellite is large enough that remnants are likely to survive atmospheric re-entry and strike the Earth, sometime in late February or early March, says Gordon Johndroe, a spokesman for the National Security Council.Is that normal?"This is relatively routine in that satellites de-orbit all the time," says Johndroe. Pieces of uncontrolled debris heavier than two tonnes -- mostly discarded rocket stages -- crash to Earth as often as once every three weeks, says Jonathan McDowell, an astronomer and launch observer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.Many discarded pieces retain some power, so that controllers on Earth can guide them to a point far from human habitation, usually using a final dive into an ocean. In 2001, Russian space officials broke up the old Mir space station in this way over the South Pacific. That's not the case for this US one, however."Obviously, we want to take a look at the potential for it to land in a populated area," says Johndroe.What are the chances of it crashing through my roof?Exceedingly slim, says McDowell. Remember that some 70% of the Earth is water, and most lands are void of people. "There is no reason for people to get alarmed about it," he says.According to the NASA Orbital Debris Program Office, there have been no confirmed instances of serious property damage or injury caused by crashing debris in 40 years.