One of Patrick's "News" stories got me thinking about asteroid and comet impacts again. Recall there was division on the "nuke 'em" strategy on this list. The other favorite strategy was re-direction although this seemed optional only with extremely advanced notice, decades and up. Rethinking it, a 1-kilometer object could be reduced to small rocks, rubble, and dust with repeated detonations of conventional explosives- no nukes needed. It might take dozens to hundreds of such "blockbuster" warheads, but the final result is more assured than resorting to a nuke, which some pointed out may leave several large, still dangerous-sized chunks. By whittling away with smaller explosions on the surface, this danger is eliminated. Think of it as "accellerated ablation". You can tailor the charges to fit the desired erosion rate/average debris size. A special missle-carrying spacecraft could be constructed. The warheads don't even need to be on rockets- they could be accellerated electromagnetically, or even just fired from a mechanical device- spring loaded, pneumatic, centrifugal, whatever. For that matter, they could be launched from earth or earth orbit, repeatedly- strung-out in a line all the way from launch site to target, in numbers calculated to do the job, plus a safety margin. Larger objects could be possibly be eroded similarly, up to a point, by adjusting the delivery schedule and warhead yields. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com