My concern with some of these smaller hab modules being proposed is the personal space issue.I get the feeling that, if you decided that, say, each of the projected four crew people needs about three square meters of personal space, some of these companies would say "Sure, no problem! Let's see, you just need to order 18 of them, then..."
Quote from: the_other_Doug on 08/16/2016 04:57 pmMy concern with some of these smaller hab modules being proposed is the personal space issue.I get the feeling that, if you decided that, say, each of the projected four crew people needs about three square meters of personal space, some of these companies would say "Sure, no problem! Let's see, you just need to order 18 of them, then..."The requirement for 4 astronauts for a 60 day mission is 25^3m per astronaut of habitable space. Some of the proposed DSH concepts as you noted will be less then ideal, further the more interfaces on the DSH the more leaks - for instance with a leak rate of 000.05% per day for the entire system, with a 1000 day mission period, 50% of the atmosphere is lost and must be replenished. This is one of the reasons why larger modules are preferred.
Quote from: BrightLight on 08/16/2016 05:05 pmQuote from: the_other_Doug on 08/16/2016 04:57 pmMy concern with some of these smaller hab modules being proposed is the personal space issue.I get the feeling that, if you decided that, say, each of the projected four crew people needs about three square meters of personal space, some of these companies would say "Sure, no problem! Let's see, you just need to order 18 of them, then..."The requirement for 4 astronauts for a 60 day mission is 25^3m per astronaut of habitable space. Some of the proposed DSH concepts as you noted will be less then ideal, further the more interfaces on the DSH the more leaks - for instance with a leak rate of 000.05% per day for the entire system, with a 1000 day mission period, 50% of the atmosphere is lost and must be replenished. This is one of the reasons why larger modules are preferred.Thanks for the clarification as to space requirements for crew, I was just tossing out a number for the sake of argument; I knew the actual number was likely larger. And I agree with your observations on leak rates, too -- the more interfaces, the more leaking you'll get. It's inevitable.Besides, everyone knows that a proper planetary spaceship is a long, cigar-shaped single module with long, tapering swept-back fins that serve as the landing legs...
Quote from: the_other_Doug on 08/16/2016 05:23 pmQuote from: BrightLight on 08/16/2016 05:05 pmQuote from: the_other_Doug on 08/16/2016 04:57 pmMy concern with some of these smaller hab modules being proposed is the personal space issue.I get the feeling that, if you decided that, say, each of the projected four crew people needs about three square meters of personal space, some of these companies would say "Sure, no problem! Let's see, you just need to order 18 of them, then..."The requirement for 4 astronauts for a 60 day mission is 25^3m per astronaut of habitable space. Some of the proposed DSH concepts as you noted will be less then ideal, further the more interfaces on the DSH the more leaks - for instance with a leak rate of 000.05% per day for the entire system, with a 1000 day mission period, 50% of the atmosphere is lost and must be replenished. This is one of the reasons why larger modules are preferred.Thanks for the clarification as to space requirements for crew, I was just tossing out a number for the sake of argument; I knew the actual number was likely larger. And I agree with your observations on leak rates, too -- the more interfaces, the more leaking you'll get. It's inevitable.Besides, everyone knows that a proper planetary spaceship is a long, cigar-shaped single module with long, tapering swept-back fins that serve as the landing legs... Good stuff all the way around (seriously and not so much). Of course, it will also need airlocks at least at both ends so crew can EVA around the outside to backdoor any unfriendlies contained within (reference: "It, The Terror From Beyond Space").
Quote from: Coastal Ron on 08/08/2016 10:56 pmHave you listened to any of the feedback from Scott Kelly after his one year mission?Where does one find this?
Have you listened to any of the feedback from Scott Kelly after his one year mission?
Probably plenty of reasons, but I'm still wondering.None of the companies is suggesting a truncated cone shaped HAB module that is just large enough to fit the payload adapter for Orion. A module that has 5 meters diameter at one end, and 8 meters at the other. For a length of 7 meters, this would seem to have about 40% larger pressurized volume than the 5.5 meters diameter cylinder. And probably 50% more habitable volume.In case a node module is added and two of this modules are connected to it at their narrow end, organizing the interior space should not be very difficult. You get the same volume in 3 SLS launches instead of 4, so some of the extra cost would be mitigated by that.
Probably plenty of reasons, but I'm still wondering.None of the companies is suggesting a truncated cone shaped HAB module that is just large enough to fit the payload adapter for Orion. A module that has 5 meters diameter at one end, and 8 meters at the other. For a length of 7 meters, this would seem to have about 40% larger pressurized volume than the 5.5 meters diameter cylinder. And probably 50% more habitable volume.In case a node module is added and two of this modules are connected to it at their narrow end, organizing the interior space should not be very difficult.
Quote from: CTC on 09/20/2016 03:26 pmProbably plenty of reasons, but I'm still wondering.None of the companies is suggesting a truncated cone shaped HAB module that is just large enough to fit the payload adapter for Orion. A module that has 5 meters diameter at one end, and 8 meters at the other. For a length of 7 meters, this would seem to have about 40% larger pressurized volume than the 5.5 meters diameter cylinder. And probably 50% more habitable volume.In case a node module is added and two of this modules are connected to it at their narrow end, organizing the interior space should not be very difficult. You get the same volume in 3 SLS launches instead of 4, so some of the extra cost would be mitigated by that.The optimum shape for containing pressure is a sphere. After that the simplest form for containing pressure is a cylinder, which is why most of the modules on the ISS are cylindrical in shape. Deviating from optimal shapes result in pressure vessels that have forces acting on them at odd angles, which must be reinforced, especially at structurally weaker areas, making them heavier. Number 1 consideration for all things space travel related is weight.
Quote from: whitelancer64 on 09/20/2016 04:12 pmQuote from: CTC on 09/20/2016 03:26 pmProbably plenty of reasons, but I'm still wondering.None of the companies is suggesting a truncated cone shaped HAB module that is just large enough to fit the payload adapter for Orion. A module that has 5 meters diameter at one end, and 8 meters at the other. For a length of 7 meters, this would seem to have about 40% larger pressurized volume than the 5.5 meters diameter cylinder. And probably 50% more habitable volume.In case a node module is added and two of this modules are connected to it at their narrow end, organizing the interior space should not be very difficult. You get the same volume in 3 SLS launches instead of 4, so some of the extra cost would be mitigated by that.The optimum shape for containing pressure is a sphere. After that the simplest form for containing pressure is a cylinder, which is why most of the modules on the ISS are cylindrical in shape. Deviating from optimal shapes result in pressure vessels that have forces acting on them at odd angles, which must be reinforced, especially at structurally weaker areas, making them heavier. Number 1 consideration for all things space travel related is weight. So to take the best of both worlds and use the available volume, the pressurized space should be a cylinder with a diameter 5.5 meter. Then to use the volume of the aft end of the adapters, items can be mounted around the aft end of the cylinder.
Maybe it makes more sense to outfit the Hab on Earth and send it up on a dedicated flight. Then co-manifest Orion and the Node on the second flight.
Maybe it ma Is the Orion Service module capable of moving an additional 40mt to cis-lunar orbit from LEO?
Quote from: BrightLight on 09/22/2016 03:22 pmMaybe it ma Is the Orion Service module capable of moving an additional 40mt to cis-lunar orbit from LEO?No, and the SM is not a stand alone stage
Quote from: Jim on 09/22/2016 03:48 pmQuote from: BrightLight on 09/22/2016 03:22 pmMaybe it ma Is the Orion Service module capable of moving an additional 40mt to cis-lunar orbit from LEO?No, and the SM is not a stand alone stageI didn't think of the SM as a stand-alone stage as it would need GNC and a lot of communications - which is not part of the SM. You did answer a bigger question as to why a number of logistics flights are needed for a Cis-Lunar facility as their appears to be no way to get large-mass components to lunar orbits.
You did answer a bigger question as to why a number of logistics flights are needed for a Cis-Lunar facility as their appears to be no way to get large-mass components to lunar orbits.
Quote from: BrightLight on 09/22/2016 04:18 pmQuote from: Jim on 09/22/2016 03:48 pmQuote from: BrightLight on 09/22/2016 03:22 pmMaybe it ma Is the Orion Service module capable of moving an additional 40mt to cis-lunar orbit from LEO?No, and the SM is not a stand alone stageI didn't think of the SM as a stand-alone stage as it would need GNC and a lot of communications - which is not part of the SM. You did answer a bigger question as to why a number of logistics flights are needed for a Cis-Lunar facility as their appears to be no way to get large-mass components to lunar orbits.Wouldn't the EUS perform the transfer in this example?