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SpaceX doesn't do GEO launches as far as I know, only GTO. I don't know whether from a lack of capability or whether they're not allowed/certified for that, tho

by ygra 10y ago

SpaceX doesn't do GEO launches as far as I know, only GTO. I don't know whether from a lack of capability or whether they're not allowed/certified for that, though. I guess an expendable F9 should easily be able to get to GEO.

toomuchtodo 10y ago
SpaceX does GEO since December 2013. http://www.spacex.com/press/2013/12/03/spacex-successfully-completes-first-mission-geostationary-transfer-orbit http://www.spacex.com/press/2013/12/03/spacex-successfully-c...
- 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 ago
    Yes, 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 ago
      It 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 ago
      Several 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.
- the8472 10y ago
  that's GTO. the payload itself will have to to provide the rest of the thrust to circularize that to GEO. But they can do so cheaply with ion engines since they don't need to fight the atmosphere.
walrus01 10y ago
Something like 95% of the commercial for profit launch market is for geostationary telecom satellites. In terms of launches per decade o3b is an aberration. GTO is the highly elliptical transfer orbit for a hohmann transfer to geostationary. This is of course a drastic oversimplification.
InclinedPlane 10y ago
Lack of capability, the 2nd stage doesn't live long enough to do it (yet). They could make the modifications to do direct GEO missions but it's a niche market and not particularly worth it, at least not yet.

by ygra 10y ago

toomuchtodo 10y ago

SpaceX does GEO since December 2013. http://www.spacex.com/press/2013/12/03/spacex-successfully-completes-first-mission-geostationary-transfer-orbit http://www.spacex.com/press/2013/12/03/spacex-successfully-c...

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 ago
  Yes, 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 ago
    It 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 ago
    Several 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.
the8472 10y ago
that's GTO. the payload itself will have to to provide the rest of the thrust to circularize that to GEO. But they can do so cheaply with ion engines since they don't need to fight the atmosphere.

walrus01 10y ago

Something like 95% of the commercial for profit launch market is for geostationary telecom satellites. In terms of launches per decade o3b is an aberration. GTO is the highly elliptical transfer orbit for a hohmann transfer to geostationary. This is of course a drastic oversimplification.

InclinedPlane 10y ago

Lack of capability, the 2nd stage doesn't live long enough to do it (yet). They could make the modifications to do direct GEO missions but it's a niche market and not particularly worth it, at least not yet.