Quote from: redliox on 05/11/2017 03:10 pmQuote from: jpo234 on 05/11/2017 02:37 pmQuote from: sghill on 05/11/2017 01:41 pmSupporting 100 people for months in zero-g requires new systems and techniques. 100 bored passengers needing to eat, poop, and clean themselves are going to be a mess.I don't think that this is a high priority item for SpaceX. Initially we will mostly see unmanned freighters and manned ships with a relatively small exploration crew (less than 20, I assume). That's based on Paul Woosters recent presentation were he said: "We have a lot of margin for early missions, which is quite helpful.". "a lot of margin" IMHO precludes 100 passengers.Right - it's going to be a while yet before we see 100-person crews. It is indeed going to be a massive pain supporting 100 people for 6-month-some voyagers...but developing an ECLSS precursor that can handle something in the 5-20 person range ought to be possible and also possible to incrementally refine. It will likely take a combination of NASA input and SpaceX's 'aggressive persistence' to go from 5 to finally 100.The initial crew size is a strawman argument. They've got to design the spacecraft now for maximum crew size. ECLSS isn't something that is bolted on board and changes with crew sizes. Plumbing and storage tanks will be integral to the design from Day 1.If it's easier on the systems with a smaller crew sobeit, but that doesn't change the immediacy of the design need.
Quote from: jpo234 on 05/11/2017 02:37 pmQuote from: sghill on 05/11/2017 01:41 pmSupporting 100 people for months in zero-g requires new systems and techniques. 100 bored passengers needing to eat, poop, and clean themselves are going to be a mess.I don't think that this is a high priority item for SpaceX. Initially we will mostly see unmanned freighters and manned ships with a relatively small exploration crew (less than 20, I assume). That's based on Paul Woosters recent presentation were he said: "We have a lot of margin for early missions, which is quite helpful.". "a lot of margin" IMHO precludes 100 passengers.Right - it's going to be a while yet before we see 100-person crews. It is indeed going to be a massive pain supporting 100 people for 6-month-some voyagers...but developing an ECLSS precursor that can handle something in the 5-20 person range ought to be possible and also possible to incrementally refine. It will likely take a combination of NASA input and SpaceX's 'aggressive persistence' to go from 5 to finally 100.
Quote from: sghill on 05/11/2017 01:41 pmSupporting 100 people for months in zero-g requires new systems and techniques. 100 bored passengers needing to eat, poop, and clean themselves are going to be a mess.I don't think that this is a high priority item for SpaceX. Initially we will mostly see unmanned freighters and manned ships with a relatively small exploration crew (less than 20, I assume). That's based on Paul Woosters recent presentation were he said: "We have a lot of margin for early missions, which is quite helpful.". "a lot of margin" IMHO precludes 100 passengers.
Supporting 100 people for months in zero-g requires new systems and techniques. 100 bored passengers needing to eat, poop, and clean themselves are going to be a mess.
I'd bet money that SpaceX is not skimping on the sophistication of their ITS ECLSS. Any takers?
Quote from: Robotbeat on 05/16/2017 02:01 amI'd bet money that SpaceX is not skimping on the sophistication of their ITS ECLSS. Any takers?Over time sure. But not at the expense of getting to Mars sooner than someone else. Just how much will it cost for the first test flight? What does a replacement unit cost? So for a $10B budget is there room to gamble on ones dream to goto Mars?So I believe they would put their investment in the flight hardware and then the life support system later. Cargo flights will be first anyway and the next window would not be for another 26 months/ That is added time to get a crew version ready ( Dragon cargo to Dragon 2 crew example ).
Quote from: RocketmanUS on 05/16/2017 02:26 amQuote from: Robotbeat on 05/16/2017 02:01 amI'd bet money that SpaceX is not skimping on the sophistication of their ITS ECLSS. Any takers?Over time sure. But not at the expense of getting to Mars sooner than someone else. Just how much will it cost for the first test flight? What does a replacement unit cost? So for a $10B budget is there room to gamble on ones dream to goto Mars?So I believe they would put their investment in the flight hardware and then the life support system later. Cargo flights will be first anyway and the next window would not be for another 26 months/ That is added time to get a crew version ready ( Dragon cargo to Dragon 2 crew example ).I'm saying I think they're probably working on a (very good) ECLSS right now. Doesn't mean they won't have a backup. ISS carries oxygen candles just in case.
The pressurised volume is going to be fixed early in the design and will be for 100 people.
The typical Mars trip is relatively short. Because of this, in some aspects, open loop systems are lighter and definitely less complex. I wouldn't rule them out.OTOH the Mars surface systems have to operate indefinitely, but have an environment to interact with, (and are not zero g) so are not really related.I won't be too surprised if they end up with simple chemical CO2 scrubbers - if nothing else then because of reliability.
Quote from: chalz on 05/16/2017 09:40 amThe pressurised volume is going to be fixed early in the design and will be for 100 people. If I could bet somewhere, I would bet that they will never carry 100 people on ITS. It is capability advertisement, like the A380 stating it can take +800 people, when in reality it takes less than 60% of that value.Maybe we should stick the discussion with smaller crew sizes.
The BFS could carry two systems. One for micro gravity of space and the other for Mars gravity as needed.
Musk proposed even more passengers for a follow-on, like 200+.I don't see why your unfounded opinion that SpaceX isn't serious about large numbers of passengers should dictate the course of the discussion.
Quote from: RocketmanUS on 05/16/2017 01:55 amThe BFS could carry two systems. One for micro gravity of space and the other for Mars gravity as needed.ISTM optimising an ECLSS system to work in both environments would add a lot of complexity. I could certainly see how there would be good reason to have two separate systems. Cheers, Martin
I don't see open loop systems having as much value as closed loop systems.Anything organic will have incredible value on Mars- even human wastes. They may not want to use it immediately, but compost delivered to Mars would be mind-boggling expensive for what it is, so it won't go to waste, IMHO.
Quote from: MP99 on 05/18/2017 03:47 pmQuote from: RocketmanUS on 05/16/2017 01:55 amThe BFS could carry two systems. One for micro gravity of space and the other for Mars gravity as needed.ISTM optimising an ECLSS system to work in both environments would add a lot of complexity. I could certainly see how there would be good reason to have two separate systems. Cheers, MartinIf there's one thing I think SX have shown it's that they are very wary of "optimization." Good enough to get the job done seems to be more their style, preferably with enough growth designed in to allow the system to stretch.
On that basis the first version of ITS will fly with a V1.0 ECLSS. My guess is it will be quite conservative for the initial size of crew ITS will carry (lots of empty slots in the appropriate racks) but SX gain experience and send more people the racks will fill up and they will feel OK with reducing the necessary margins. I'm thinking of way the Merlin engine has evolved from the initially ablative cooled version to the one we know today.