Chicken Little May Make Appearance In February, March

While it appears Mars won't get hit by that asteroid this week -- and Earth will be spared in its own close encounter with an interstellar traveler -- scientists now say our planet will get hit by one of our own man-made satellites in late February, or early March.

An American spy satellite, built by Lockheed Martin and launched from Vandenberg Air Force Base a little over a year ago, stopped responding to commands from earth shortly after it got into orbit. That has produced two problems.

First, the inability to command firings of the satellite's maneuvering rockets, thought to be fueled by hydrazine, has allowed the satellite's orbit to decay. The second, and related problem is that the satellite may fall to earth with a nearly full tank of hydrazine, which would be hazardous if it reached the ground.

Current bets are the tank will rupture from the heat of re-entry -- producing a fireball which will be visible to the naked eye, but posing no overt danger to those on the ground.

Because of the secretive nature of the satellite's mission, there's not much information available about what's on board... but John Pike, director of Globalsecurity.org, told the New York Times the spacecraft could contain toxins, including beryllium, which is often used as a rigid frame for optical components.

Jonathan McDowell, a space program analyst and an astronomer at the Harvard-Smithsonian Center for Astrophysics, told the Times satellites re-enter the atmosphere every few months, and usually land far from people, because so little of the earth's surface is actually populated. Call it, "the big-ground theory."

But, he added, "...one could say we’ve been lucky so far."

FMI: www.globalsecurity.org, www.nasa.gov