Friday, September 23, 2011

Space Junk: NASA Can't Predict Re-Entry With Certainty

Re-entry of the NASA's abandoned UARS satellite into earth's atmosphere is expected in the early evening today. While NASA maintains that it will not be over North America at that time, they also insist it's too early to predict the time and location of re-entry with any certainty.

Some 26 chunks of the old NASA satellite -- roughly the size of a bus -- will be dropping straight down at hundreds of miles per hour over an area of some 500 square miles at some point Friday night.

"We believe that the risk is sufficiently low that no one needs to, to change their behaviors," NASA's Mark Matney said Thursday.

As UARS – short for Upper Atmosphere Research Satellite - enters the atmosphere, everything changes. Bit by bit, pieces will cross the threshold about 60 miles up, enter the atmosphere and then drop straight down like stones -- travelling at several hundred miles an hour depending on their shape.

The chunks will fall at different points along the satellite's path, meaning debris will cover 500 miles.

This is the largest NASA satellite to fall back to Earth uncontrolled since Skylab in 1979.

Bill Ailor, principal engineer of the Aerospace Corporation, studies incoming space junk for the Air Force. He says that some frighteningly huge pieces of other satellites have come crashing down into villages, farms-and random datelines around the planet.

"I actually think a lot of this kind stuff comes down and nobody knows what it is and just thinks it's junk and ignores it," Ailor told ABC News.

The Aerospace Corporation, a private firm that is tracking UARS, offered a more specific prediction, saying the satellite would likely come down off the coast of Chile at 6:06 p.m. EST.

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