I understand that all satellites must have burn corrections to keep their orbits where they are needed. However my question is specifically about what those changes are in magnitude from the desired orbit for a geostationary satellite, and specifically the altitude changes. If uncorrected, would not the satellite simply return to its " main" altitude in a periodic path? If so, what is the time period - above its main, and below its main, during one day? (Is this period induced mainly by the moon's gravity?)
My question is: No matter how small the altitude changes might be during an average mass satellite's geostationary orbit, are the changes mostly predictable and periodic (mainly Moon's gravity?) - and allow the orbit to continue - and what is the range of those altitude changes (X meters, kms, etc) ?