earlier, your favorite space movie. you said it was "the martian" because it was one of the most realistic except for two things. what were those? >> the two things -- well, the two major things in "the martian" that were shortcoming, the first was they didn't treat the matter of radiation. one needs to shield for radiation and they didn't talk about that at all. it was just an assumption that it was done, but it's certainly a major be and the other one is that the -- -- the atmospheric pressure at the surface of mars is 6 millibars or it's the altitude that spy planes fly. when the win blows it's not blowing over a rocket. and so, you know, when i talked to matt damon after graduation he said but maria we needed