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SpaceX doesn't do direct GEO insertion, only boosting to a Geostationary Transfer Orbit (GTO) which is the norm for satellites headed to GEO. The satellite itse
by InclinedPlane 10y ago
SpaceX doesn't do direct GEO insertion, only boosting to a Geostationary Transfer Orbit (GTO) which is the norm for satellites headed to GEO. The satellite itself does the circularization, which isn't hugely costly fuel wise but requires a stage that can restart after coasting all the way to GEO altitude (several days), which SpaceX currently lacks (the 2nd stage runs on batteries).
- walrus01 10y agoYes, exactly this. GEO requires an engine that is low kN thrust but can be restarted many times. The Wikipedia page for the Russian fregat which is commonly used as a 3rd or 4h stage for their launches is a good example of such hardware. If you're patient you can even circularize a GTO with ion engines, which has been done on some partially-failed telecom satellite launches.
- the8472 10y agoIt has also been done by design instead of a fallback. http://www.boeing.com/features/2015/01/bds-702sp-01-26-15.page http://www.boeing.com/features/2015/01/bds-702sp-01-26-15.pa...
- InclinedPlane 10y agoSeveral of the most advanced GEO commsats use that as their main way to get into orbit. By beefing up the ion engine enough to circularize the orbit at GEO you make for cheaper launch costs and a longer lived vehicle.