- I didn't see the retro rockets firing at all. It seemed like the capsule hit the ground at 17 mph, and the commentator was saying, 'beautiful soft landing'.
The retro(s?) fires for less than half a second, as I understand it. I don't have a hard figure for that though. 17 mph is 25 fps, one G is 32 fps^2, so less than a second at 1G.