This is pretty awesome -
http://www.youtube.com/watch?v=Ki_Af_o9Q9s"We've got literally seven minutes to get from the top of the atmosphere to the surface of Mars, going from 13,000 miles an hour to zero," Tom Rivellini, a NASA engineer, tells the camera with a grim face and deadpan delivery. "If any one thing doesn’t work just right, it's game over."