I have spent a lot of hours with Kerbal Space Program recently and I am curious about one thing.
I got into orbit around the Moon and then I was able to get back to an orbit of "Kerbin" (the home planet in this game, similar to Earth) and land successfully.
I did not have much fuel left, therefore I wanted to save as much as possible for anything that might happen during landing. When I was at my Apoapsis (which was as far away as the Moon) from Kerbin I used fuel to get my periapsis to only 50km, while Apoapsis remained the same. The trajectory was very "ellipse-like".
What happened? When I was aerobraking at 50km with more than 3000m/s speed, the apoapsis was decreasing, while periapsis remained almost the same. Then I was catapulted "back into space", but with a shorter trajectory around Kerbin.
I did this multiple times and after some time, my speed at periapsis decreased to 2400m/s and after that, the apoapsis got as low that I stayed in the atmosphere and landed.
The point is - I did not have to use as much fuel to get low orbit, I slowed down a lot by repeating "slow a little with aerobreaking and then go back to space".
I am curious - why this is not used in reality? At least I did not hear about it. I am thinking that probably real materials do not take lightly to "burning and freezing" multiple times...?
PS : This is a copy of an astronomy question This site is more relevant.