Quote from: Will on 06/03/2014 01:46 amQuote from: aero on 06/02/2014 11:27 pmI think the question should be: Is there anything that CST-100 has over Dragon v2?Abort propellant that's less toxic than hypergolics. The ability to use unused abort propellant in gimbaled thrusters for ISS reboost. More experience with in-space ECLSS. Willingness to use whatever launcher is most promising rather than only the one made by the company that made the spacecraft. The first two are reasonable points for CST-100.The third isn't about CST-100, it's about the organization building CST-100, and there's no evidence it will give CST-100 anything Dragon V2 doesn't. We could make all sorts of statements about Boeing and SpaceX as companies, but the question was about actual design features of CST-100 versus those of Dragon V2.The final item also doesn't translate to anything concrete for CST-100. "Willingness" is vague. What's actually planned is for it to have one launch vehicle, Atlas V. Falcon 9 has been mentioned as a possibility if plans change, but it would clearly be a lot of work and would require SpaceX to agree to it. It wouldn't be any technically harder or easier to switch Dragon V2 from F9 to Atlas V than to switch CST-100 from Atlas V to F9. The only reason nobody has talked about that is that F9 is so much cheaper than Atlas V and doesn't have engines made in Russia, so there's no reason to switch. In fact, the talk of possibly switching CST-100 from Atlas V to Falcon 9 just highlights the fact that Dragon V2's plan-of-record launch vehicle is pretty compelling.
Quote from: aero on 06/02/2014 11:27 pmI think the question should be: Is there anything that CST-100 has over Dragon v2?Abort propellant that's less toxic than hypergolics. The ability to use unused abort propellant in gimbaled thrusters for ISS reboost. More experience with in-space ECLSS. Willingness to use whatever launcher is most promising rather than only the one made by the company that made the spacecraft.
I think the question should be: Is there anything that CST-100 has over Dragon v2?
DC pros: - lifting body design, horizontal landing - can switch launch vehicles
Somehow I just like wings, because it seems safer than depending on rockets or parachutes to operate correctly, wings are just there, they do not have to be deployed.
- Dragon V2 + F9R - 140mil per mission - CST-100 + Atlas V 401 - 250mil per mission - DC + Atlas V 401 - 200mil per mission
Don't know what their RCS uses.
DC pros: - lifting body design, horizontal landing - ....
Both DC and CST100 have the Atlas V issue to cope with.
DC cons: - might be locked to Atlas V
Quote from: Hauerg on 06/15/2014 08:06 amBoth DC and CST100 have the Atlas V issue to cope with.Not an issue for commercial and NASA missions
CST-100 pros: - conservative, low risk capsule design - Boeing as a proven provider - could switch launch vehicles (although not likely)CST-100 cons: - higher (or even highest) cost per flight - boring
Quote from: Jim on 06/15/2014 11:47 amQuote from: Hauerg on 06/15/2014 08:06 amBoth DC and CST100 have the Atlas V issue to cope with.Not an issue for commercial and NASA missionsSure, it's an "issue." Since the entire future of the Atlas V is an "issue", given the current situation with the Russian government having announced it won't honor the former RD-180 engine contracts it had formerly signed.
No, again the RD-180 Was Made an issue by an orchestrated program. Will say it until i'm blue in the face, correctly manufacturing the RD-180 is a purely political decision. The decision is not one of manufacturing know how or ability.
Quote from: aero on 06/03/2014 07:16 amI left Orion out because it is not commercial crew. The following post is a good start I think.One should also consider these options and consider if there is a realized advantage vs Soyuz and the cost savings...Soyuz: Pros: Proven, safe, operational, affordable (... in other words <<< $1B/year)Cons: Requires astronaut training in another country. Flight services may be ending by 2020 (could be continued).
I left Orion out because it is not commercial crew. The following post is a good start I think.
Be patient people, rockets are hard.