everything from how the human body reacts to extended time in space to physics of spacecraft to landing on different objects to what kind of dried food tastes best etc..

mercury made gemini possible because it showed that they could get a hunk of metal with a person in it into space and back safely. gemini made apollo possible because it showed that humans can work and interact in space for longer periods of time. apollo made _______ possible because it showed how to aim for a target, launch something so big, coordinate movements happening millions (?) of miles away, computing power needed 'n shit like that, blahblahblah. if nasa wasnt so cash strapped towards the end of apollo, there definitly would've been something else that built up on the knowledge gained from apollo to go out even further, which we're doing now as we speak with mars.


and don't say how i only named a couple. i'm no nasa guy.