Benson
2008-05-27 09:00:24
I wish I understood your response, Brett, so I should shut up. But — I’d like to try one more time. If I’m leaving Mars, I do have to exceed escape velocity. But if the trajectory is exactly the opposite, meaning my intent is to arrive rather than take off, then my concern is to brake to a slow enough speed so the impact is tolerable. I ignore escape velocity, and merely adjust braking power as needed, so I reach zero velocity on touchdown. But because the robot lander can’t fine-tune its braking power as it descends, and because escape velocity is an expression of gravitational attraction, escape velocity must be taken into account when programming the landing. Have I got it now?
