Air Bags for Planetary Defense

Gallowglass writes "The Canadian paper, the National Post, is reporting on a plan to divert asteroids headed towards Earth. According to the story, the proposer, a Dr. Hermann Burchard, suggests deploying an inflatable mylar bag a few kilometers in size, and using it to push the projectile aside. An air bag for earth? The deployment mechanism isn't detailed in the story."

Comments

Airbag? I believe this is the wrong word.

[redhotchil]

Using the word "Airbag" for this idea definitely gives people the wrong idea. An airbag is used usually to reduce the impact of a fast moving object. In the case it is used as a deflection mechanism. Perhaps the word deflection ballon would be a better combination word?

Just a thought.

Easily misunderstood

[El]

The problem the author is trying to solve is: How do you get a grip on an asteroid for long enough for your rocket motors to change it's path without causing the asteroid to break up. He's suggesting using a giant pillow between engine and asteroid to destribute the force.

This is the wrong problem, in my opion; he assumes you've got massive amount of rocket fuel to wast. What we really need to do is figure out how to take some of the mass of the asteroid and accelerate it, using this as the reactant to change the path. Sort of like installing a rail gun on the asteroid, and firing off bits of asteriod like b-b's to get the asteroid to move in the opposite direction.

Re:Easily misunderstood

[PleaseDontBeTaken]

Isn't that really the same problem? If you are bringing your own power, in whatever form, you have a finite amount of energy you can expend in whatever combination you want to change the momentum of the asteroid. Your solution sounds slightly better because after the first shot, the remaining asteroid would have ever so-slightly less mass. But when you consider the problem of mounting a rail gun on some asteroid in a stable fashion...well, the combination of rockets and the super-pillow sounds a lot easier, which counts for a lot when you are a million miles from the nearest astro-workshop and the clock is ticking.

Of course if you can use external sources of energy, like solar energy (i.e. the solar sail) or asteroid itself, then you really solve one problem. But whatever your solution, if it is really to solve the problem, it also needs to have a rate of work sufficient to deflect the trajectory in the time you have remaining. If the asteroid is big enough to matter, let's hope we have lots of leadtime.