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There is still a good chance they might do a FH Raptor-powered second stage :)

• nkoren 9y ago
  A higher-impulse second stage on the Heavy would make sense in payload terms, but have you seen anything from SpaceX indicating that they actually are thinking about doing this? My understanding of their design philosophy is that they prioritise the operational efficiencies of only having one type of engine and one type of propellant to worry about on the pad.
  • greglindahl 9y ago
    SpaceX's initial money from the Air Force for Raptor involved the possibility of a new Raptor-powered FH upper stage. There's no sign that such a stage is still planned (or was ever seriously considered, really.)
    • nkoren 9y ago
      Huh, I'd forgotten about that -- thanks. Yeah, I doubt it was seriously considered. Probably just didn't want to tell the Air Force what they were really planning to use the Raptor for. Can't say I blame them!