capcom Mar 9 Oct 2007 - 21:54
D'après CNN
If something goes wrong in the tense moments before a space launch, such as an explosion of noxious gases or a fire on the launchpad, future astronauts could escape harm -- on a roller coaster.
Chris Bergin, editor of the independent Web site NASASpaceFlight.com, recently unearthed a confidential NASA study of emergency egress systems (EES) in which the authors recommended using mini railcars, docked at the top of a 350-foot-tall launch tower, to speed crews down a track to ground level in a heart-pumping 4.5 seconds.
If you're imagining astronauts screaming "Whee!" inside their helmets with their gloved hands in the air, you're not far off: Roller-coaster engineers served as consultants on the design, Bergin says.
Other escape plans under consideration include a faster version of the current EES for space-shuttle flights -- baskets suspended from cables, which astronauts have, thankfully, never had to use -- as well as a high-speed elevator and a "slide tube."
At press time, NASA wouldn't specify a front-runner, but Kennedy Space Center's Bruce Buckingham says a new EES will be in place for the launch of the shuttle's successor, Orion, as early as 2012.
Here's how it works:
STEP 1: Hop in and buckle up. At the first sign of danger, astronauts dash from the crew vehicle across the top of the launch tower and buckle into an enclosed four-seat mini car. Up to four cabs would be lined up on the track to accommodate other escaping launch and rescue personnel.
STEP 2: Prepare to drop. A crew member inside unlocks the unpowered coaster from its safety catch, sending the car down a tubular track to the base of the tower. As with many modern amusement-park steel rocket "screamers," gravity keeps the coaster wheels locked to the track, and the enclosure protects astronauts from smoke, toxic leaks and flying debris.
STEP 3: Hold onto your lunch. Traveling at a gravity-induced 100 miles per hour, the cab rolls about 1,200 feet along a ground track to a safe area or bunker located inside the launch zone. A passive magnetic and friction braking system similar to those used on amusement-park rides decelerates the cabs. Total time from launchpad to bunker: about 88 seconds.
STEP 4: Relax. The evacuated crew exit the roller-coaster car into the safety of a covered and ventilated area, which can hold 21 people in sealed comfort for up to an hour until the danger has passed.
