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Look out below: Satellite coming back to Earth

By Dale Kiefer - 21 Sep 2011 11:50:0 GMT
Look out below: Satellite coming back to Earth

Be on the lookout for falling satellite debris over the next few days. According to NASA, its Upper Atmosphere Research Satellite (UARS) is expected to reenter Earth's atmosphere on about Sept. 23, after six years of service in space.

Although the satellite will break up upon re-entry, not all of the pieces are expected to burn up in the atmosphere.

Officials stress, however, that since the dawn of the space age in the late 1950s, no one has ever been injured by a falling piece of space debris, nor has any significant property damage resulted from falling space junk.

Although all manmade objects in space are tracked by the Joint Space Operations Center of U.S. Strategic Command at Vandenberg Air Force Base, Calif., it's impossible to predict precisely when space junk will reenter the atmosphere--or where it will fall.

Remarkably, more than 22,000 objects in excess of 4 inches are presently circling the globe, and only about 1,000 of those objects are operational spacecrafts. The rest represents the accumulating detritus of mankind's more than 50 years in space.

The heavily shielded International Space Station is designed to withstand collisions with "orbital debris" of less than half an inch (1 cm) in diameter, but has to perform "collision avoidance maneuvers" about once a year.

Some orbital debris circles the globe just a few years before plunging back to Earth, but junk at the highest altitudes (greater than 620 miles, or 1,000 km above Earth) may continue to orbit the planet for a century or more before eventually falling.

NASA appears to recognize that something's got to give. In 2010, the National Space Policy featured a section, for the first time, entitled "Preserving the Space Environment". The new policy is aimed at minimizing additional contributions to the growing junkyard in near-Earth orbit.

Top Image Credit: © NASA