how did we first know that there’s is no gravity in space before we sent the very first satellite? And that we only needed a limited amount of fuel to propel the rocket out of earth’s atmosphere?

Question

Were there conditions created on earth to see how space would be like? What was the theory based on if an experiment was conducted? Or what’s it literally just – let’s just send it up and see what happens to it?

In: Physics

Answer 1

There is gravity in space. But people knew long before we went there, that in an orbiting spaceship, you’d feel weightless.

That fact was worked out by:

a: observing the orbits in our solar system
b: using our calculations about those orbits to figure out how gravity pulls masses together
c: doing some “what if a man was in a falling elevator car” type thought experiments about free-fall

That was all they needed to do to work this out. No rocket-building needed.