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

NASA Satellite: Narrowing Down the Impact Zone

By NED POTTER (@NedPotterABC) , GINA SUNSERI and KEVIN DOLAK

Sept. 23, 2011

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.

NASA/Getty Images

The Upper Atmosphere Research Satellite... View Full Size

NASA Satellite: Narrowing Down the Impact Zone Watch Video

NASA Tracking Where Satellite Will Hit Watch Video

Animation: NASA Satellite's Final Plunge Watch Video

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.
Ailor said the time and location would almost undoubtedly change as Friday afternoon approaches. He and his colleagues study the materials they find in a lab to figure out what will burn up and what will become a potential threat -- just like the pieces of the UARS satellite.
But according to Nicholas Johnson, NASA's chief orbital debris scientist, any one person's chances of getting hit by debris are tiny -- something like 1 in 21 trillion. The chances that of the 7 billion people on Earth, one of them, somewhere, could be hit are more like 1 in 3,200.
Despite those odds, Ailor says that a hazard is a hazard.
"Five hundred pounds of stainless steel represents a hazard -- if you're standing under it," Ailor joked.
To say the least.

SatelliteAR Android app now tracks falling UARS, helps you avoid being smooshed

By Lydia Leavitt posted Sep 23rd 2011 11:13AM

You may have a better chance of winning the lottery or running into Captain Kirk at the mall, but when it comes to being impaled with pieces of the now defunct Upper Atmosphere Research Satellite as it plummets towards Earth, it's better to be safe than sorry. The SatelliteAR Android app has added a temporary feature that gives stargazers the ability to monitor this space junk's trajectory to avoid impact when it re-enters the atmosphere sometime later today. NASA has assured us that the bus-sized satellite won't land anywhere in North America, but if it touches down at night, people on the ground could witness a pretty sweet light show wherever it does land. Android users determined to avoid a Wicked Witch of the East-like fate can download the app at the source link below and check out the video demo after the break.

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