Seldom considered in writing about using a nuclear bomb on incoming comets is the effect of blasting it into smaller pieces. Each piece slightly pushed sideways in its trajectory, but each much smaller mass.
Rocky asteroids and metallic objects? Less likely to split up, but the modern wave-of-hand bit of using thrusters (since nuclear bombs are yucky on campus) seems to always “First, let us assume the object is a uniform spherical cow.”
Yes, a bomb imparts little blast impulse sideways. We need way of “pushing” a solid, irregular, long and spinning irregular mass in space.
Yawn
> Seldom considered in writing about using a nuclear bomb on incoming comets is the effect of blasting it into smaller pieces... Yes, a bomb imparts little blast impulse sideways.
The use of a nuke involved blowing mass off one side to adjust its trajectory, a nudge done early enough wouldn’t have to be particularly powerful. The issue with trying to deflect one of these is, the actual mass would be easier to accurately measure by trying to move it this way.
The best option is to be ready by compiling accurate data on the rare objects moving in retrograde. One of those could be of appropriate trajectory, position, and mass to act as a projectile, and deflectable without use of a nuke to meet the threatening object. The head-on impact of the two would release more energy than a nuke, and vaporize a big chunk of the larger object’s mass, likely shatter it, and alter its trajectory (-ies).
Far enough out, a canister of compressed air discharging on the same x-y-z axis during the objects rotation (if any) at the right place creates course deviation. All you need is the thing to skip off the atmosphere — better if you can nudge the thing into the sun’s gravity well.
Redirect it with a lander consisting of its own propulsion plus a propulsion unit to change it by the few degrees necessary to render orbit to safe one.