I learned the concept when watching the tv shows on the first Apollo missions as a six-year-old boy. That centrifugal forces compensate for the gravitational pull in any stable orbit on all stuff in that orbit. Thank you, Prof. Heinz Haber, for always being precise on that when commenting the missions there on TV.

Later I found a good description of what happens there in one sequel of Douglas Adams "A Hitchhiker's Guide to the Galaxy": where he described the more general concept of flying as "falling towards the ground but missing it". The concept does not work in general (of course :)) but it is appropriate description what is happening with any object orbiting a mass.