>What aspects of MCT/BFS could be tested out on the F9H upper stage? Which technologies, subsystems, or components would F9H Raptor stage be best suited to flight-test? What might the evolutionary upgrade path for this upper stage look like?
Musk has stated there will be no development of upper stage reusability on either F9 or FH hardware. Why would you not take his words at face value?
I don't have more than a gut feeling for this, but I'd push the timeline back five years for the introduction of the MCT, towards 2028 or so. It ultimately took SpaceX almost ten years to get where they wanted to be with the Merlin, so I'd expect them to take a few years to get the Raptor where they want it to be. Raptor flight engineering would probably keep the design of the MCT in some degree of flux as well.
I generally do take his words at face value, but the reason for not having a F9/h second stage return was money.
And the money situation is something that CAN change, it not being an immutable law of physics, as shown by the Air Force Raptor contract.Whether they do it? Up to them of course, I'm thinking they won't.
I've come to the realization that SpaceX changes plans quite a lot, and sometimes rapidly. I can point to several examples here, but I think you're all aware of them.
Quote from: JamesH on 01/19/2016 10:11 amI generally do take his words at face value, but the reason for not having a F9/h second stage return was money.A curious way to put it. IIRC Musk called it "uneconomic" to do upper stage reuse due to the limited performance of LOX/RP1. Exactly why it is inadequate remains extremely vague. Quote And the money situation is something that CAN change, it not being an immutable law of physics, as shown by the Air Force Raptor contract.Whether they do it? Up to them of course, I'm thinking they won't.No I don't think they will either.
So pushing reusability to Raptor based upper stage enables SpaceX to focus on their weak spot (high energy trajectories) and develop a stage similar to ACES. So I think that the Raptor upper stage will be designed to enable reusability through modifications but will not support it initially, much like for the first stage. It will be added mainly to offer cost effective tests of MCT technologies.
A curious way to put it. IIRC Musk called it "uneconomic" to do upper stage reuse due to the limited performance of LOX/RP1.