VolvoRacerNumber5 t1_iqywdop wrote on October 4, 2022 at 2:42 AM

Reply to comment by ciroluiro in After DART: Using the first full-scale test of a kinetic impactor to inform a future planetary defense mission by EricFromOuterSpace

I think everyone here is ignoring how material gets ejected by the impact. They know the momentum of both the spacecraft and asteroid very well. There's nothing new the impact will show in regards to that very basic momentum conservation problem.

What they are actually trying to characterize is the way debris is ejected by the impact. This ejecta carries off its own momentum and can impart a significant additional momentum to the asteroid.

ciroluiro t1_iqz47cw wrote on October 4, 2022 at 3:48 AM

But that's kinda my point. Anything ejected would only "push off" the asteroid and help nudge it off course, given that they mostly get ejected either in the opposite direction to the spacecraft, or perpendicularly in a roughly even manner (this last one is speculation on my part since I imagine it depends heavily on the angle of impact and possibly more things I don't know, but I don't think it's a wild assumption)