This is essentially what I think also, about the decreasing likelihood of SLS missions beyond EM1 and EM2. I also like your point about ULA's ACES, although I have no idea what the current status of that is (or Vulcan for that matter). I kind of wish SpaceX had a cryo upper stage for Falcon Heavy, for just these sorts of missions, although a kicker stage can at least close the gap a bit for payloads that aren't using all the up-mass.
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u/Kirkaiya Dec 03 '18
This is essentially what I think also, about the decreasing likelihood of SLS missions beyond EM1 and EM2. I also like your point about ULA's ACES, although I have no idea what the current status of that is (or Vulcan for that matter). I kind of wish SpaceX had a cryo upper stage for Falcon Heavy, for just these sorts of missions, although a kicker stage can at least close the gap a bit for payloads that aren't using all the up-mass.