If NASA had faked the entire space programme, you'd of thought they would get three blokes who had the slightest inkling of charisma, who would engage us and convince us that it had taken place, they would describe eloquently what it was like, what they did & how they felt throughout etc...
It was Newton actually!
http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html
This is incredibly simple, basic physics. Newton worked it out 400 years ago without going anywhere near space or even a vacuum!
Its called Inertia! Newton worked that one out 400 years ago...
Inertia (inertia is a body's resistance to acceleration):
An object remains in rest, or remains at a constant speed, unless forces from outside are acting on it.
The ball in the experiments of Galilei was continuously influenced...