Yeah, I'm also wondering if moving up the door a little wouldn't be cheaper than modifying the whole architecture.
Yes, that would help a lot. We could also avoid common bulkheads. The problem is that MLAS needs to be fully developed.
1) Is post-rollout integration of the LAS itself, from a crane in the open air, feasible?
Quote from: Burninate on 09/07/2014 07:43 pm1) Is post-rollout integration of the LAS itself, from a crane in the open air, feasible?Wow! It breaks the concept of LC-39 operations, but ... yeah. Were you imagining integration of the LAS just outside the VAB, or at the pad?
Doing the [common bulkhead] insulation was a PITA...
I keep being mystified regarding the aversion to common bulkheads. It was done 45 years ago for LOX/LH2, and at 10m diameter even. So why?
For the SLS core I'm pretty sure the decision was based on schedule. The core found itself on the critical path. Separate tanks meant essentially zero schedule risk....
Quote from: Lars_J on 09/07/2014 11:22 pmI keep being mystified regarding the aversion to common bulkheads. It was done 45 years ago for LOX/LH2, and at 10m diameter even. So why?Do you mean for upper stages, or boosters? For the SLS core I'm pretty sure the decision was based on schedule. The core found itself on the critical path. Separate tanks meant essentially zero schedule risk....
There is a nice movie about the Saturn V stage w. common bulkhead. LH2 is so cold it would freeze the LOX. Doing the insulation was a PITA...
Quote from: jg on 09/07/2014 11:38 pmDoing the [common bulkhead] insulation was a PITA...Yes but, "No pain, no gain," and to do the trade requires quantifying both the pain and the gain in terms of both dollars and schedule.
Since you are not using the SLS core why not just make it wider?
0) One or two RS-25 on the u/s instead of J2.
Move u/s O2 tank above the H2 tank, and somehow wrap it around the CPS's RL10s.
Just out of curiosity, why are you trying to do the mission in one launch?
Quote from: Steven Pietrobon on 09/07/2014 07:12 amYes, that would help a lot. We could also avoid common bulkheads. The problem is that MLAS needs to be fully developed.Sure. But so, too, do your 6 engine first stage, 2 engine second stage and your entire lander. I'd think once you're going THAT far, what's a bit more effort for the MLAS? I mean, seriously ...
Quote from: sdsds on 09/08/2014 01:00 amQuote from: jg on 09/07/2014 11:38 pmDoing the [common bulkhead] insulation was a PITA...Yes but, "No pain, no gain," and to do the trade requires quantifying both the pain and the gain in terms of both dollars and schedule.The reason why they bothered was that the LEM+Apollo capsule got heaver than expected, and they could not redesign everything; the weight had to be saved somewhere. That happened to be the SII second stage. There are easier ways to get the 7900lb's saved.The only people they could find who could do the insulation work successfully were surfers who had been working on building surf boards; the problem was that if the surf was up, they'd lose schedule, as their workforce would head for the waves!
Quote from: MP99 on 09/07/2014 05:46 pm0) One or two RS-25 on the u/s instead of J2.The RS-25 is about the same height as J-2X, so I don't think that helps much.