Another key feature a new upper stage should have is a non-detachable fairing, because if you want to land a payload on Mars you can't expose it during entry. But perhaps it might still be detached and recovered separately in LEO missions?I don't know why you expect a reusable upper stage on top of Falcon Heavy to have a 70 ton payload, that is higher than the maximum for a fully-expendable Falcon Heavy stack. I'd expect that the performance gain from switching to Raptor will be much less that what is lost in attempting to make it reusable and the difference will have to made up from using a larger booster.It's also very dubious that they would build a special stage only for a few flights as it sort of defeats the purpose of reusability. Maybe if they somehow manage to build it to the same diameter as the early ITS and still fit it on the Heavy?Perhaps a Falcon Heavy + Reusable Upper Stage could be cheaper to operate than a Falcon 9 + Expendable Upper Stages. This would require very fast and cheap refurbishment of multiple boosters.
Scaled-up Dragon - about 7 meters in diameter across the base? Or slightly larger even than that? I'm thinking something that would fit inside an 8.4 meter SLS style payload fairing. Or a similar sized fairing on another BFR.
The trouble with a small precursor to ITS is that it doesn't benefit from the mass/volume equation in the same way, making EDL quite a different thing. Additionally, keeping cryogenic fluids cold on a trip to Mars would be much harder.
...I don't know why you expect a reusable upper stage on top of Falcon Heavy to have a 70 ton payload, that is higher than the maximum for a fully-expendable Falcon Heavy stack. I'd expect that the performance gain from switching to Raptor will be much less that what is lost in attempting to make it reusable and the difference will have to made up from using a larger booster.It's also very dubious that they would build a special stage only for a few flights as it sort of defeats the purpose of reusability. Maybe if they somehow manage to build it to the same diameter as the early ITS and still fit it on the Heavy?Perhaps a Falcon Heavy + Reusable Upper Stage could be cheaper to operate than a Falcon 9 + Expendable Upper Stages. This would require very fast and cheap refurbishment of multiple boosters.
I've personally been using RUS interchangeably with a mini BFS.
The trouble with a small precursor to ITS is that it doesn't benefit from the mass/volume equation in the same way, making EDL quite a different thing. Additionally, keeping cryogenic fluids cold on a trip to Mars would be much harder. I think a smaller-than-ITS Mars ship would just about work for a flags and footprints mission, but a tiny craft isn't a goer. Fine for LEO, good as an alternative to SLS locally, but that's it.
RUS, the thing that I am vehemently against, is either a stock stage with methane or a wider one with methane that operates like the existing stage. There is no point to these configurations.An mini BFS/ITS as MG describes has some merit but......a. It would only operate out of LC-39Ab. SLC-41 and/or Boco Chica have be up and running smoothly to keep the cash comingc. It would be after FH and Dragon 2 are flying smoothly. d. DOD is not going to use F9 or FH for vertically integrated payloadse. It won't happen for 2020 because of c & d, unless LC-39B is used.
RUS, the thing that I am vehemently against, is either a stock stage with methane or a wider one with methane that operates like the existing stage. There is no point to these configurations.An mini BFS/ITS as MG describes has some merit but......a. It would only operate out of LC-39Ab. SLC-40 and/or Boco Chica have be up and running smoothly to keep the cash comingc. It would be after FH and Dragon 2 are flying smoothly. d. DOD is not going to use F9 or FH for vertically integrated payloadse. It won't happen for 2020 because of c & d, unless LC-39B is used.
e. It won't happen for 2020 because of c & d, unless LC-39B is used.
Quote from: Jim on 06/26/2017 02:03 pme. It won't happen for 2020 because of c & d, unless LC-39B is used.LC-39B is the SLS pad. Do you know or suspect that something bad will happen to this plan?
d. DOD is not going to use F9 or FH for vertically integrated payloads
Quote from: Jim on 06/26/2017 02:03 pmd. DOD is not going to use F9 or FH for vertically integrated payloadsThat is interesting. I would be inclined to believe that SpaceX does not want to develop vertical integration for the Falcon family, but that they would do it if DOD asks. However I have never heard before that DOD does not WANT SpaceX to develop that capability. Thats a pretty strong statement. Do they simply put all VI payloads on Atlas and Delta?