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Re: New Mitigation Strategy Minimizes Risk Of Asteroid Collisions

Ron Baalke wrote:
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> 
> April 1998
> 
> New mitigation strategy minimizes risk of asteroid collisions
> 
> CHAMPAIGN, Ill. -- The spectacular plunge of Comet Shoemaker-Levy 9 into
> Jupiter in July 1994 and recent concern about the projected "near miss" of
> Asteroid 1997 XF11 with Earth in October 2028 brought renewed awareness that
> collision events do occur within our solar system -- and the next one could
> involve our planet. In fact, such a collision may be long overdue, and steps
> should be taken to alleviate the risk, a University of Illinois researcher
> says.
> 
> "If faced with this kind of danger, we would want to send a spacecraft to
> intercept the object as far from Earth as possible," said Bruce Conway, a
> professor of aeronautical and astronautical engineering. "This would allow
> whatever mitigation strategy we use to have the longest time to act."
> 
> There are two practical problems that must be solved, however, Conway said.
> "The first is simply getting a sizable payload to the object in the shortest
> amount of time, and the second is deciding what to do when we get it there."
> 
> In a paper published in the September-October (1997) issue of the Journal of
> Guidance, Control, and Dynamics, Conway described the optimal low-thrust
> interception of a potential collider. The proposed mission scenario would
> combine the speed of conventional chemical rockets with the increased
> payload capability of continuous-thrust electric propulsion. Having arrived
> at the destination, however, what should be done to prevent the impending
> collision?
> 
> "For years, we assumed that the best mitigation strategy was to blow up the
> object with a nuclear warhead," Conway said. "But that may not be such a
> good idea. If we blow it up, instead of having just one large mass hurtling
> toward the Earth, we could end up with a multitude of smaller -- but equally
> lethal -- objects coming at us. A better alternative would be to deflect the
> object."
> 
> One possible mechanism to accomplish this would involve detonating a nuclear
> warhead above the asteroid surface, Conway said. "That would create a
> crater, and a large portion of the jet of vaporized material would shoot off
> in one direction -- like a rocket -- and push the object in the opposite
> direction."
> 
> But which direction should the object be pushed to ensure that it will miss
> the Earth? And would it make more sense to speed the object up or slow it
> down?
> 
> Conway's latest research has focused on answering these questions. He
> developed an analytical method that, given the orbital parameters of the
> object and the interval between interception and close approach, determines
> the proper direction in which to push the object to maximize the deflection
> in the required time.
> 
> Such calculations may never be needed, but they're nice to have just in
> case.
> 
> "While the probability of a large asteroid or comet colliding with the Earth
> is low, the potential for destruction is immense," Conway said. "It's
> probably not something we should lose sleep over; but, on the other hand, it
> would be really silly not to do anything."


This sort of thing is news?  I would like to believe the researcher is
at least somewhat aware of work that has gone on at DOE workshops and
elsewhere.  He is not the only scientist/engineer that has ever
considered cosmic billiard balls and the advantage of a "long lever
arm."  Hopefully there is something unique in his work.
References: