NASA has initiated a process that raises questions about the future of its Orion spacecraft. So far, this procedural effort has flown largely under the radar, because it came in the form of a subtle Request for Information (RFI) that nominally seeks to extend NASA’s contract to acquire future Orion vehicles after Exploration Mission-2, which likely will fly sometime between 2021 and 2023.Nevertheless, three sources familiar with the RFI, who agreed to speak on the condition of anonymity, told Ars there is more to the request than a simple extension for Orion’s primary contractor, Lockheed Martin. Perhaps most radically, the RFI may even open the way for a competitor, such as Boeing or SpaceX, to substitute its own upgraded capsule for Orion in the mid-2020s.
Star liner in particular should have no big problem with adding more propellant except it makes abort more sluggish.
The 2 big problems I can see with switching off Orion are SLS compatibility and the service module, specifically the available Delta-V. Orion has around 1.3 KM/S in the SM, and I'd think both Dragon and CST-100 would have significantly less, being designed for LEO ferry operations. So any proposal would need to account for the cost of adding extra propulsion to either craft.
Starliner at least could probably use an ACES as a tug for BEO missions. ULA has studied this option before. SpaceX doesn't have anything available off the shelf, but they could fit a decent propellant load plus a couple (Super?)Dracos in the trunk, and this would almost certainly be much cheaper than continued Orion development.
As for SLS compatibility, I see little reason for that to be a requirement. Vulcan and FH can perform the job just fine, though distributed launch may be needed to deliver any additional payloads and fuel (still cheaper than an SLS launch, and doesn't require SLS to be manrated if that program continues)
or even Dream Chaser.
Do Starliner and Dragon have enough ECLSS endurance to be useful in cislunar space? I did some searching but I haven't been able to find CCtCAP ECLSS requirements.
Elephant in the room; ITSThey say a mid-20's replacement which coincides with SpaceX's timeline, by definition it'll have a long duration ECLSS, large internal propellant stores, and its cargo capability would eliminate the need for developing a large cargo lander for Mars. Crew size: no problem.Just saying...
Have NASA's CEV, Constellation, SLS/Orion dates been better? Even if Spaceship testing slips 5-6 years it beats SLS/Orion to Mars.
Quote from: docmordrid on 11/10/2016 11:34 PMElephant in the room; ITSThey say a mid-20's replacement which coincides with SpaceX's timeline, by definition it'll have a long duration ECLSS, large internal propellant stores, and its cargo capability would eliminate the need for developing a large cargo lander for Mars. Crew size: no problem.Just saying...If SpaceX can build, test and fund the entire thing on their own by that time, while building a revolutionary ECLSS system of unprecedented scale, I'll honestly be very impressed. But I'm not going to count on it, especially with SpaceX's dates.