Greenhouse gases in the lower atmosphere, which are on the rise, trap heat, triggering cooler temperatures in the upper atmosphere, which serves to keep space junk in orbit longer. Five studies conducted since 2000 have all reached the same conclusion: temperatures in the upper atmosphere are showing a 10 percent decrease overall, about a difference of 70 or 80 degrees, Tobiska said. "We need to start taking into account atmospheric cooling and that's what we as a community as starting to do," he said. Even with a perfectly timed hit, the military's troubles are not over. Atmospheric physics can carry debris far from an intended fall zone. Wreckage from the space shuttle Columbia, for example, was spread over 2,000 square miles. "Pieces of old Russian and U.S. rockets have been found washed up on the shores of remote islands in the Pacific," said Scott Hubbard, a member of the board that investigated the 2003 Columbia accident. The military plans to target its wayward satellite when it is about 160 miles above Earth. "Once it hits the atmosphere, it tumbles, it breaks apart, it is very unpredictable and next to impossible to engage. So what we're trying to do here is catch it just prior to the last minute, so it's as absolutely low as possible, outside the atmosphere, so that the debris comes down as quickly as possible," said Gen. James Cartwright, vice chairman of the Joint Chiefs of Staff. "The satellite … will deorbit more quickly, and we can predict more accurately where it will de-orbit, so we can potentially put it in a position in the ocean," he said. "The worst case is we miss and then we have a known situation which is where we are today," he added. Related Links: Irene Klotz's blog: Free Space |
advertisement
Put Discovery News on Your Site!
|
-
our sites
-
video
mobile
-
shop
-
stay connected
-
corporate
