Question

How does a geostationary orbit decay as atmosphere drag is not present?

Answer 1

Answer:

Orbits do not decay without some friction-like mechanism which transfers energy from the orbital motion. ... Due to atmospheric drag, the lowest altitude above the Earth at which an object in a circular orbit can complete at least one full revolution without propulsion is approximately 150 km (90 mi).

Answer 2

Answer:

All geostationary satellites are geosynchronous. ... The “stationary” part of geostationary describes how a satellite in this orbit remains fixed with respect to an observer on the ground. This is an ideal orbit for communications satellites, since ground-based antennas can remain pointed at the same spot in the sky.