# Satellite altitude variances in orbit

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) ?

• Not all satellites need burn corrections, but those at a geostationary orbit may need it. You may read about the orbital stability and edit your question a bit. You will find most of your questions answered there. What about writing an answer by yourself after reading? – Uwe Nov 12 '17 at 20:18
• Your question is about orbital station keeping. You can take a look at that article, and also look at the existing questions and answers on this site using the Tags menu. Here's a link to the station-keeping tag: space.stackexchange.com/questions/tagged/station-keeping The task of station-keeping is very different depending on which orbit you are in. General categories are NEO, MEO and GEO (near-earth, medium, and geostationary). Geosynchronoous doesn't have an acronym. In LEO, the main effect is atmosphere and lumpy gravity. – uhoh Nov 13 '17 at 5:58
• Geostationary orbits must stay within an assigned 73km slot in orbital direction. If their altitude changed, so would their orbital velocity, and they would quickly leave their slot, so station keeping in altitude and true anomaly connected. Would it be fair to rephrase the question as "How far can the altitude of a satellite differ from geostationary so it stays in its slot for one orbit" ? Are you interested in altitude specifically rather than eccentricity? – Rikki-Tikki-Tavi Nov 13 '17 at 13:47
• Thank you! This slot you mention, is that the satellite's full range, meaning it can only be allowed to move 73km in either direction, higher or lower, or is that just the higher end range? If only the higher range, does it have a lower range too? – CRD567 Nov 14 '17 at 13:03
• It's in orbital direction, not radial direction. The satellite has to stay must not go further or lag behind so much it leaves it's assigned 73km range. Since speed and orbital radius are connected by Keppler's law, that means it has to keep the orbital radius as well. – Rikki-Tikki-Tavi Nov 15 '17 at 16:00