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Would giant air bag stop killer space rock?

'It seems a safe, simple and realistic idea'

This photo of an asteroid was taken on August 18 from Winterthur, Switzerland. Named 2002 NY40, it's 800 meters (half a mile) in diameter and passed a comfortable 522,000 kilometers (326,250 miles) from Earth -- no air bag needed in this case.
This photo of an asteroid was taken on August 18 from Winterthur, Switzerland. Named 2002 NY40, it's 800 meters (half a mile) in diameter and passed a comfortable 522,000 kilometers (326,250 miles) from Earth -- no air bag needed in this case.  


By Richard Stenger
CNN

(CNN) -- Some scientists have suggested nuclear bombs to deflect a big comet or asteroid from a collision course with our planet. One researcher has a more novel solution: a giant air bag.

An atomic detonation would do little to stop some types of asteroids, which are little more than loose collections of rubble and would absorb the energy without changing course, said Erik Asphaug of the University of California, Santa Cruz.

In fact, his computer simulations indicate that such a blast could split an incoming asteroid or comet into more fragments that remain on a collision course.

Hermann Burchard of Oklahoma State University in Stillwater thinks a big air bag could take care of such a cosmic "beanbag."

The mathematician proposes that a spacecraft could approach the object and inflate a bag several kilometers wide using a chemical reaction to make gas.

The probe would then push the bag against the incoming asteroid or comet. The bag would distribute pressure evenly and nudge the object away without fragmenting it, Burchard suggested.

"It seems a safe, simple and realistic idea," he told UK-based New Scientist magazine. "Mylar, perhaps, would be tough enough for the job."

'My gut tells me to bet against this one'

Do other space scientists think the air bag idea is a good one or just full of hot air? When asked via e-mail about the idea, Louis Friedman, director of the Planetary Society, replied first with a smiley face. Later he offered more.

"It seems impossible. The sheer scale of an air bag with sufficient momentum to nudge a 5-kilometer solid rock hurtling around the solar system at 100,000 miles an hour or so, is just beyond my comprehension," the former NASA rocket engineer said.

"Of course, on a long enough time-scale, like many centuries, I have no idea what kind of engineering will be possible. But my gut tells me to bet against this one."

Others received the idea with more enthusiasm.

"The basic idea makes sense. If a comet or asteroid is spotted with enough advance warning, then a small nudge in the right direction will change its course enough so that by the time it reaches Earth's vicinity it will fly by without colliding," said NASA's Dave Williams.

"So the air bag isn't a crazy idea. It's definitely plausible, although technically tricky, I'd imagine," said Williams, who works for the agency's National Space Science Data Center in Greenbelt, Maryland.

Asphaug goes even further than Burchard in brainstorming methods to stop killer space rocks. He likes the idea of avoiding nukes, but thinks the job could be done, without air bags, without splitting the object into more chunks, by placing a rocket engine on it and gradually thrusting it away from a collision course.

Williams agrees: "Even rubble pile asteroids are not so fragile that they need such gentle treatment, and what Eric Asphaug says is correct. Rockets applied directly to the object, even without an air bag, would probably serve to deflect it without causing it to break up."



 
 
 
 


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