been working on a physics problem and got to the end of a calculation and just realized that i had just done something no one else had done. i knew something that no one else knew. >> after seeing an ad from nasa in the stanford student paper, sally ride applied to be an astronaut. 1983, she flew on the shuttle challenger. >> it was an unbelievable honor to be chosen to be the first american woman to go into space and the thing that's given me the ability to do is to try to make a difference now in young girl's lives and try to give a little bit of it back. >> within months the shuttle program will end. the u.s. won't be able to put people back in space for years. >> i'm depressed, frankly, by the gap in our ability to launch people. >> and what of the split among astronauts whether to return to the moon or aim for mars? >> astronauts have always held their own opinions and not