Author Topic: ITS Environmental Control and Life Support System (ECLSS)  (Read 5731 times)

Online DanielW

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Re: ITS Environmental Control and Life Support System (ECLSS)
« Reply #20 on: 05/13/2017 05:32 AM »
I expect that early eclss will be a bit unwieldy and prone to needing repairs, but it will also probably be the area of spaceflight that sees the most rapid iteration and development. These systems will be going into everything from spacesuits to space ships with rovers and other equipment in-between.

Mars greatest IP export will probably be things we desperately need on earth. Better water purifiers, recycling, and manufacturing.

I suspect that many of the performance gains the ITS makes over the next few decades will come from mass savings in ECLSS.

Offline meekGee

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Re: ITS Environmental Control and Life Support System (ECLSS)
« Reply #21 on: 05/13/2017 06:58 PM »
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.
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Offline Robotbeat

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Re: ITS Environmental Control and Life Support System (ECLSS)
« Reply #22 on: 05/16/2017 01:01 AM »
I would because chemical scrubbers get very heavy and simple regenerative (not closed loop) scrubbers are very lightweight.
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Offline RocketmanUS

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 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.
Added cost to develop. they already know the first crews will be small exploration crews. As they build new BFS's in later years they would build them with the newer tech to handle greater crew size. They think they could carry as many as 200 crew, but that is a way off in the future.

I expect the first crew size to be 12 people. If on BFS has an issue crew could transfer to another BFS. So I expect the life support system to be able to handle 24 crew, This could keep the mass down so the craft could reach mars in less time.

The is the power issue and how much heat the BFS can radiate. More equipment and more crew would add more heat needed to reject. For the power the solar cell tech will need to evolve. More electrical power produced for a given mass and size.

So do to cost, time, and need of size of crew to start with i believe they will start with as much off the shelf tech as they can for a crew number of no more than 24. Later if there is a demand for crew sizes 100 or more then they or others would develop the next generation of life support systems needed for the BFS.

The BFS could carry two systems. One for micro gravity of space and the other for Mars gravity as needed.
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Offline Robotbeat

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Re: ITS Environmental Control and Life Support System (ECLSS)
« Reply #24 on: 05/16/2017 02:01 AM »
I'd bet money that SpaceX is not skimping on the sophistication of their ITS ECLSS. Any takers?
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Offline RocketmanUS

I'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 ).
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Offline Robotbeat

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Re: ITS Environmental Control and Life Support System (ECLSS)
« Reply #26 on: 05/16/2017 02:35 AM »
I'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.
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Offline RocketmanUS

I'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.
As for backup system I was thinking just a second set. However a different design would be better ( from a proven system ).

So do you think they will evolve their ECLSS over time to grow for greater crew numbers like 100?
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Offline chalz

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Re: ITS Environmental Control and Life Support System (ECLSS)
« Reply #28 on: 05/16/2017 09:40 AM »
Regarding crew sizes, some systems are going to be able to scale while others may not.

The pressurised volume is going to be fixed early in the design and will be for 100 people. Therefore the air volume is going to be pretty close to that. If you cram the space with cargo won't that just become a bacteria/fungus trap?

Water storage has long been mentioned as being needed for solar storm protection. If a crew of 10 brings only its share of water they only get one tenth the protection?

The only thing my naive brain did think could be shrunk was the laundry. No point bringing equipment to clean 100 shirts a week if you only use 10. Also toilets and showers...

Offline IRobot

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Re: ITS Environmental Control and Life Support System (ECLSS)
« Reply #29 on: 05/16/2017 09:58 AM »
The 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.

Offline john smith 19

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Re: ITS Environmental Control and Life Support System (ECLSS)
« Reply #30 on: 05/16/2017 11:55 AM »
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.
Standard NASA allowance for air/water/food is 5Kg/person/day. Open loop for a 10 person crew on a 50 day (v.fast) trip that's 2.5 tonnes. Double that for a 100 day trip (both one way).

But at 100 people you're at 25 tonnes for a 50 day voyage, 50 tonnes for a 100. Something like 75% of that mass is water, whose recovery is well understood.

People forget there are multiple ISS systems doing water, urine and air recycling. {EDIT to be clear I believe there are a couple of versions of each system IE NASA, ESA and Russia in some cases. All are a bit different and all have different strengths and weaknesses. I believe there is enough track record between them to design and build quite an effective ECLSS right now] They're all very much pilot systems but could probably all serve as the model for a working system on ITS.
[EDIT If we are serious about exploring the Solar System we cannot go on doing it by leaving a trail of urine dumps and food packaging in our wake across the system.   :( ]
« Last Edit: 05/17/2017 01:24 PM by john smith 19 »
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Offline Robotbeat

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Re: ITS Environmental Control and Life Support System (ECLSS)
« Reply #31 on: 05/17/2017 02:25 AM »
The 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.
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.
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Online sghill

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Re: ITS Environmental Control and Life Support System (ECLSS)
« Reply #32 on: 05/18/2017 03:02 PM »
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.
« Last Edit: 05/18/2017 03:03 PM by sghill »
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Online MP99



The 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

Online jpo234

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Re: ITS Environmental Control and Life Support System (ECLSS)
« Reply #34 on: 05/18/2017 03:59 PM »
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.

I don't think anybody doubts that SpaceX eventually want's these numbers of passengers. What is debatable however, is the premise of the original post, that the full scale ECLSS will be an integral part of the BFS and those has to be ready for the first manned flight.

I think, that this is not an immediate challenge. Initial missions will be exploratory with relatively small crews. These exploratory flights can use a conventional ECLSS. The full scale system is further into the future, maybe 20 years after the first manned mission or 25 to 30 years from now.

Online Negan

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Re: ITS Environmental Control and Life Support System (ECLSS)
« Reply #35 on: 05/18/2017 04:12 PM »


The 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

What systems wouldn't work in both?

Offline Kaputnik

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Re: ITS Environmental Control and Life Support System (ECLSS)
« Reply #36 on: 05/18/2017 04:15 PM »


The 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

Absolutely. There are so many differences.
An in-space ECLSS has to work without any external inputs except solar power, has to work in microgravity, and has to be optimised for low mass and reliability over the period of time for the Mars transfer flight.
A Mars surface ECLSS has to work in 0.38g, is less mass sensitive, has access to abundant external CO2 and perhaps also H2O, and will, crucially, have to synergise with other systems including propellant production and power production. Parts of the process may act as heatsinks for nuclear power sources, or as dump loads for solar. Oxygen may be produced as a byproduct of propellant manufacture (Tom Mueller said as much in the recent interview).
There is also much more scope, on the ground, for biological systems- e.g. greenhouses producing food and oxygen. The timescale, mass, and space required for these systems make sense on the ground, but not on the ITS.
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Offline john smith 19

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Re: ITS Environmental Control and Life Support System (ECLSS)
« Reply #37 on: 05/18/2017 06:52 PM »


The 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
If 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.
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Offline RocketmanUS

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.
Cost?
Reliability?
Size?
Power required?
Added heat generated needing to be expelled?
Time to develop before first crew mission?

These are some of the things that need to be looked at in order to see what system would be better for the first generation ECLSS for the BFS.
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Offline Robotbeat

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Re: ITS Environmental Control and Life Support System (ECLSS)
« Reply #39 on: 05/19/2017 01:32 AM »


The 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
If 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.
A reasonable perspective through the first 5 Falcon 9 flights.

Increasingly not so afterwards. Merlin 1D is thrust-to-weight ratio optimized to all heck (smashing previous records for any liquid engine). Mass fraction is increasingly good. I mean, they're the first group to deeply subcool rocket propellants (some Russian engines use somewhat subcooled LOx, but not nearly as deeply subcooled) for operational rockets. They stuck their COPVs in the subcooled LOx tank (which is basically the complete opposite of being wary of optimization). They don't gently land F9 like New Shepard but instead hoverslam it. ITS takes this to a whole new level (Raptor, the most insane rocket engine ever, and landing a ridiculously over powered rocket on just a launch cradle?? Are they insane??), and I'm certain the ITS ECLSS they're working on will be no different.

Quote
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.
Dragon will fly with life support. That's your ECLSS v1.0. No one ever suggested the ITS ECLSS wouldn't have margins (so I'm not sure where that comment is aimed at) since it's going to have a smaller crew to start out with, but I sincerely doubt it's anything other than an attempt at a significant improvement over the State of the Art.
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Tags: ITS ECLSS