Here's a pretty good presentation on the design constraints of Curiosity. He answers the 6 vs 7 question about 27 minutes in: it's the guided-descent phase tha

Here's a pretty good presentation on the design constraints of Curiosity. He answers the 6 vs 7 question about 27 minutes in: it's the guided-descent phase that gives the extra minute. http://www.youtube.com/watch?v=-q38AncYm2U http://www.youtube.com/watch?v=-q38AncYm2U