Geostationary Orbit is a really neat concept that was first described in 1928... Two generations before spaceflight. Arthur C Clarke expanded the idea and popularized the idea so that we now call these orbit Clarke Orbits.
And of course, the Russians took the idea and went sideways with it. Because Russia is so far north they cannot use Equatorial Geosynchronous Orbits. They use Molniya Orbits Note that these orbits are only stable over time because the Earth is not a perfect sphere; the oddities of the earth's gravity distribution help keep the orbit stable.