The basic point I was trying to make was about the validity of the economic model. To say using one LV over another would be generally less total cost cannot be made, it is a specific case by case situation.
Quote from: oldAtlas_Eguy on 10/14/2015 05:48 pmThe basic point I was trying to make was about the validity of the economic model. To say using one LV over another would be generally less total cost cannot be made, it is a specific case by case situation.Did you read the paper or is that your opinion? You do kinda sound like you have a source for your numbers...I was referencing the abstract, not to prove that SLS is always better but to show that $/kg is not necessarily the more important metric as Coastal Ron suggested.
I just created my own simplistic eco model of the problem and relationships and checked what the results were. It showed that while the $/kg difference between the two launchers is important it is not the controlling factor but the factor of total modules to unique module designs.
Quote from: oldAtlas_Eguy on 10/14/2015 11:37 pmI just created my own simplistic eco model of the problem and relationships and checked what the results were. It showed that while the $/kg difference between the two launchers is important it is not the controlling factor but the factor of total modules to unique module designs.This assumes the construction method is based on assembling modules, and that may not be the ultimate design, or at least not a majority of the ultimate design. For instance, with a rotating space station quite a bit of the total mass will likely be taken up by supports and floors and such, not living space, and those would likely be more mass dense than living space modules would be (with no real designs, "likely" is the operative word).However, this discussion about rotating space stations is really premature, since based on my calculations the mass of such stations, even if they are only .5G or so, would be far, far bigger than the mass of the ISS, which is 450mT. And I don't see any funded need for such a structure in the near future.
QuoteThe L point station should also be modular enough to have replacements periodically for continuous operations. It should also be able to expand into a fuel depot for Mars transits, and a warehouse type depot for Mars cargo departures.Using Earth analogies, we don't combine hotels with gas stations, for a number of reasons, but even in space I'm not sure there would be enough synergy or need to combine them.
The L point station should also be modular enough to have replacements periodically for continuous operations. It should also be able to expand into a fuel depot for Mars transits, and a warehouse type depot for Mars cargo departures.
So since the adapter/interstage is shown as being foam covered as well as the core would the two likely be joined before foam is applied or can the foam be applied to both and then connect the two parts?
Quote from: rayleighscatter on 10/22/2015 10:32 pmSo since the adapter/interstage is shown as being foam covered as well as the core would the two likely be joined before foam is applied or can the foam be applied to both and then connect the two parts?I don't think the adapter is foam covered. It's just painted orange to match the tanks for some reason. It has to be painted, so why not orange (other than flying carrot jokes)?But in my opinion, it should be white. The tanks are only orange because that's the natural color of the foam insulation, and they don't want to paint it, in order to save weight. Not because orange is the cool color now. Or ever, in spite of OITNB.Mark S.
Critical design reviews for the individual SLS elements of the core stage, boosters and engines were completed successfully as part of this milestone. Also as part of the CDR, the program concluded the core stage of the rocket and Launch Vehicle Stage Adapter will remain orange, the natural color of the insulation that will cover those elements, instead of painted white.
Quote from: Mark S on 10/23/2015 03:49 amQuote from: rayleighscatter on 10/22/2015 10:32 pmSo since the adapter/interstage is shown as being foam covered as well as the core would the two likely be joined before foam is applied or can the foam be applied to both and then connect the two parts?I don't think the adapter is foam covered. It's just painted orange to match the tanks for some reason. It has to be painted, so why not orange (other than flying carrot jokes)?But in my opinion, it should be white. The tanks are only orange because that's the natural color of the foam insulation, and they don't want to paint it, in order to save weight. Not because orange is the cool color now. Or ever, in spite of OITNB.Mark S.The LVSA is covered in foam now. Not sure why, but it is, per this:http://www.nasa.gov/press-release/nasa-completes-critical-design-review-for-space-launch-systemQuoteCritical design reviews for the individual SLS elements of the core stage, boosters and engines were completed successfully as part of this milestone. Also as part of the CDR, the program concluded the core stage of the rocket and Launch Vehicle Stage Adapter will remain orange, the natural color of the insulation that will cover those elements, instead of painted white.
I have no idea why they would put foam on the LVSA. Does anyone else have any insight on that decision?
The post-CDR design does include more foam on the top end of the rocket after an additional decision included a call for the LVSA (Launch Vehicle to Stage Adaptor) to have foam on the outside, based on the latest thermal analysis.Given the LVSA has the core stage LOX tank below it, the ICPS LOX tank inside, and the ICPS LH2 tank above it, it is expected this area of the rocket will become cold during the final countdown and form ice on the outside.
Presently, SLS Near-Term Look-Ahead schedules show that the VAC will be turned over from the construction contractor ESAB to Boeing at the end of this week on 31 October.
... because for every pound of paint applied, a pound of payload delivery ability would have been removed from SLS’s capability.
Quote... because for every pound of paint applied, a pound of payload delivery ability would have been removed from SLS’s capability. Is that correct ?
Like you, I have no idea why they would put foam on the LVSA. Does anyone else have any insight on that decision?Mark S.
Also insulated with the orange foam is the Launch Vehicle Stage Adapter, the conical section that connects the core stage with the upper stage. Because this section widens so much from top to bottom, it will experience extreme aerodynamic heating during launch, and the foam will protect the metal underneath from the high temperatures.
That's interesting. I wonder what makes launch heating on the SLS adapter more problematic than it would have been on the Saturn V second-third stage adapter.