Relativistic Weapons

[EDG]

Ah right , ta.

Yeah I think the trick is to reduce the tangential velocity of the asteroid to zero, then it should hit the planet. But it's still going to be fiddlier to do than just to fire and forget about it.

 

[atpollard]

Good thing people arn't trying to do something similar, like landing a probe on Mars. Aparently, they would miss a lot.

 

[EDG]

Good thing people arn't trying to do something similar, like landing a probe on Mars. Aparently, they would miss a lot.

There's a bit of a difference. For starters, the modern spaceprobes aren't under constant acceleration - that's basically set at the start and all it does during the cruise to the planet is make a few course corrections, then (if it's an orbiter) it does a big burn on its thrusters to get into orbit around the planet.

And we're talking about a huge rock under constant acceleration from several AU out here, not low energy Hohmann Transfer Orbits.

Though frankly, the relativistic rock thing is just ridiculously unnecessary anyway. You can just send a rock in from that far out without any extra acceleration, and the impact would still be pretty damn impressive as it's picking up speed by falling into the sun's gravity well. And you could basically just do it like a modern spaceprobe - give it the right acceleration to start with to put it on a planet-crossing orbit to hit the target at the right time, and watch nature do the rest. There's absolutely no need for any further acceleration beyond that.

 

[lastbesthope]

And we're talking about a huge rock under constant acceleration from several AU out here, not low energy Hohmann Transfer Orbits.

Ahh, Hohmann transfers, that brings back fond memories of Bi-elliptic transfer calculations.

LBH
(Genuine rocket scientist you know)