How hard is it to land on the Martian surface?
Getting to Mars is actually (relatively) easy; it’s landing that’s tricky. In order to get to Mars the Virgle ships will need to build up enough delta v that when we reach the planet we’ll be traveling on the order of 3 miles per second, with a quite heavy ship. Recall your high school physics: kinetic energy rises with the square of speed, and all this energy has to go back to zero when we land. One way might be to use atmospheric friction to slow down — but the Martian atmosphere is so thin that we won’t have enough altitude to slow down fast enough to avoid crashing. So our mission plan will have to employ a combination of technologies to land the staging, mission and crew vehicles, including biconics, split body flaps, feathered reentries and vectored impulse breaking.
