However the design and capabilities of rigid pressure hulls is well understood, including secondary radiation issues. Inflatables are not, and won't be for a long time.
Quote from: Dalhousie on 05/30/2016 11:36 pmHowever the design and capabilities of rigid pressure hulls is well understood, including secondary radiation issues. Inflatables are not, and won't be for a long time.I would think that the properties of these materials are well known too and allow precise calculations of constructions, particularly radiation issues, including secondary radiation.Or is this a case of needing to test if it hurts, when you hit your thumb with a hammer every time you buy a new hammer?
No it is not. Rigid pressure hulls are very well understood well tested with 55 years operational. Inflatable pressure hulls are far less known.
There is a lot of exaggerated claims associated with inflatables. They may well have their uses, but they are not a panacea.
We got some more detail on this Mars Architecture from FISO presentation by Steve Jolly & Steve Bailey on July 27. Links to the audio & slide presentations below.audio linkslides linkIn summary. The proposal is to do manned mission to the Martian Moons with a vehicle stack with about 11 SLS size payloads plus SEP development and ground systems for the Martian Moons. Big budget needed.
One consideration with rovers. You could send more low quality rovers rather than 3 Curiosity class vehicles. That way, the crew could drive them more aggressively. They could take risks such as exploring caves and other dangerous locals that you wouldn't dare send your more expensive robot into.
Quote from: Zed_Noir on 07/30/2016 07:37 pm...Lockheed's idea still sounds promising to me. If they can combine this with MSR they could make even a one-shot visit to the Martian moons a worthwhile endeavor.
Did you listen to the full audio? Jolly & Bailey were talking about semi-permanent orbital Mars camp. A terrible idea IMO. Since the cost of this proposal will preclude any manned missions on the Martian surface for a very long time.
I find this concept unconvincing.
Orion plus service module without fuel is around 17t, so if you have two of them that is 34t, as much as the habitat itself. That's without the taxi propulsion stages. For comparison, the mass of the Phobos taxi in EMC is 13.5t, of which the crew module is probably around 5t.Moreover, in this architecture neither the Taxis nor the return fuel are pre-deployed with SEP (which is silly since they actually use SEP for the other components).
I think it's a very inefficient architecture. The only good thing about it is that it uses SEP to spiral the parts from LEO to cis-lunar space (if I understood correctly).Quote from: Zed_Noir on 07/31/2016 06:14 amDid you listen to the full audio? Jolly & Bailey were talking about semi-permanent orbital Mars camp. A terrible idea IMO. Since the cost of this proposal will preclude any manned missions on the Martian surface for a very long time.But an orbital base camp is likely low cost. It's only this architecture which manages to make orbital Mars missions into "Battlestar Galacticas".
Quote from: Oli on 07/31/2016 07:19 amOrion plus service module without fuel is around 17t, so if you have two of them that is 34t, as much as the habitat itself. That's without the taxi propulsion stages. For comparison, the mass of the Phobos taxi in EMC is 13.5t, of which the crew module is probably around 5t.Moreover, in this architecture neither the Taxis nor the return fuel are pre-deployed with SEP (which is silly since they actually use SEP for the other components). Exactly why I'm not fond of Orion use beyond Cislunar. I know the architecture proposed by Langley used SEP for both cargo and crew (the later to a lesser extent).
The in-space propulsion stage looks like an ACES or the EUS is upgraded with ACES tech. ACES will have long duration coast with low boiloff. Something that the SLS EUS being designed will not have. Also if the assumed LV is changed to using just a Vulcan/ACES with distributed launch the 6 SLS flights at up to $1B each is replaced with 6 sets (1 + 2 tanker) of Vulcan ACES launches at ~$0.5B per set. A savings of $3B in launch costs for the program ($6B SLS, $3B Vulcan/ACES). Also Vulcan/ACES (12 per year) would have a higher launch rate of as little as 18 months for all the launches vs 3 years for SLS (2 per year) to do all the launches.Added:3 missions assuming SLS as LV for $26B over 3120 days.5 missions assuming Vulcan/ACES for $27B over 3120 days.
Quote from: oldAtlas_Eguy on 07/31/2016 05:09 pmThe in-space propulsion stage looks like an ACES or the EUS is upgraded with ACES tech. ACES will have long duration coast with low boiloff. Something that the SLS EUS being designed will not have. Also if the assumed LV is changed to using just a Vulcan/ACES with distributed launch the 6 SLS flights at up to $1B each is replaced with 6 sets (1 + 2 tanker) of Vulcan ACES launches at ~$0.5B per set. A savings of $3B in launch costs for the program ($6B SLS, $3B Vulcan/ACES). Also Vulcan/ACES (12 per year) would have a higher launch rate of as little as 18 months for all the launches vs 3 years for SLS (2 per year) to do all the launches.Added:3 missions assuming SLS as LV for $26B over 3120 days.5 missions assuming Vulcan/ACES for $27B over 3120 days.SLS is not $1billion each, but $500 million.
The ESD Budget Availability Scenarios produced in 2011 indicate a cost of about $2.6 billion (in FY2025 dollars) for one 130-tonne SLS launch per year, and $3 billion for one 130-tonne and one 70-tonne launch per year. To my knowledge, that's the only hard data we have on what SLS will cost to operate (and note that it's an increase over the annual budget during development), but it's not very hard. A figure of $500 million has definitely been floated by NASA, but it seems that could only be a marginal cost, and it may be no more than a hope.
"We've estimated somewhere around the $500 million number is what an average cost per flight is," SLS deputy project manager Jody Singer, of NASA's Marshall Space Flight Center in Huntsville, Ala., said Tuesday during a presentation at the American Institute of Aeronautics and Astronautics’ SPACE 2012 conference in Pasadena, Calif."