Author Topic: Airlocks for Mars Colony  (Read 13626 times)

Offline DusanC

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Re: Airlocks for Mars Colony
« Reply #20 on: 01/22/2017 05:50 PM »
I bet the opposite. We'll use the suits SpaceX is developing for Mars first. SpaceX is not developing a suit port.

SpaceX is not developing a suit port for travel to ISS.

We don't know what are they developing for Mars.

IMHO suit port is much better than airlock for Mars.

Offline lamontagne

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Re: Airlocks for Mars Colony
« Reply #21 on: 01/22/2017 05:55 PM »
Dust removal should be done before entering the airlock, say in an anteroom, preferably by robotically articulated arm CO2 sprayers [...]
Hand held vacuums won't work in low (Martian atmosphere) pressure; they are too slow and inefficient even in Earth conditions with an assistant doing the vacuuming.  Impossible to self-clean those hard to reach areas.

There's a big gap between "handheld vacuums" and "robotic arms spraying CO₂ snow".

Hand-held pressurised CO₂ "air"-hoses, fixed frame CO₂ "air curtains"/"air blades", hand-held brush-hose combinations (such as you use to clean your car, but with CO₂ instead of water), etc.

Regarding dust: how about a liquid "car-wash" type sprayer to get the dust off after the pressure is sufficiently high.  The liquid would be filtered and recycled.

I don't think you would use water for cleaning, since you then have to design every component to be water-proof. (Not just pressure vessels (which should be okay, obviously) but every support system around the pressure vessel.)

And if you're going to that much trouble, you might as well go all the way to a wet-lock and get rid of the airlock entirely
Water tolerant is not water proof. All trucks on Earth are water tolerant.
http://www.kkewash.com/Specialised-Mining-Vehicle-Wash-Equipment/Mining-Equipment-Truck-Wash-System.html

I actually spec'ed some of these for mining garages.  There are not that complex.

« Last Edit: 01/22/2017 06:04 PM by lamontagne »

Offline AncientU

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Re: Airlocks for Mars Colony
« Reply #22 on: 01/22/2017 06:48 PM »
The goal here, for daily use, is to move humans between surface suits and inside living/working areas.  Maintenance can be handled differently.

NASA already has surface suit concepts where humans will access the suit through a hatch on the back of the suit.  Which means the amount of area that needs to be cleaned for human-transfer operations is just the hatch on the back, which likely won't be as dirty as the feet and hands of the suit.  Also there could be a cover on the "hatch" so that it stays clean during surface operations, also reducing the amount of cleaning required when "docking".

But if you want to reduce the amount of air lost when leaving a station, then one way would be to have a "balloon" inflate inside the airlock to force out as much station air as possible, then retract when suited worker is ready to leave the lock.  That should require less energy than trying to evacuate the entire lock.

Someone above mentioned 'no free lunch'... how do you retract without pumping?  Suggest you save the balloon for something more useful.
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Offline Dalhousie

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Re: Airlocks for Mars Colony
« Reply #23 on: 01/22/2017 08:17 PM »
We don't usually think this way, but co2 above 1 pct is toxic to humans. The long term occupational health level is set to 0.5 pct in the US. So whether or not the co2 in an airlock is a problem will depend on specific circumstances.

First, is the airlock volum significant compared with the indoor space the person will enter. One function of the ECLSS system for the indoor space is to remove co2 from breathable air. So if the indoor volume is 100 times the volume of the airlock, I wouldn't worr about it. But if the indoor space is small, say a small garage for 1 or 2 vehicles then we may have a concern. If the airlock contains Martian air at 96 pct co2 but the pressure is raised 20 times to match the inside air then when the interior door is opened, the amount of co2 entering may be signicant. If the indoor volume were say 10 times airlock volume then it might not take too many airlock openings to reach 1pct.

We can't be sure of operating conditions at all times, so it might be good practice to pump out as much outdoor air as we can before refilling the airlock with indoor air, not co2.

If we are employing  a double lock system as suggested here, we would be using indoor air from airlock 1 to refill airlock 2, etc. This would be a good way to conserve indoor air, which is expensive to create on Mars.

CO2 will be removed by the absorbers
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline Dalhousie

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Re: Airlocks for Mars Colony
« Reply #24 on: 01/22/2017 08:22 PM »

Robots will outnumber people, possibly permanently...


People and robots are not comparable, alternative, or interchangeable regardless of the hype and SF movies.  Robots are just tools. You might as well say that people are outnumbered by home appliances or workers outnumbered by power tools. 
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline Paul451

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Re: Airlocks for Mars Colony
« Reply #25 on: 01/22/2017 08:32 PM »
Re: Suitport type spacesuits.

The other advantage of this design is that it's donnable by one person alone. (The Russian Orlon suits also have the same type of hinged-hatch entry, even though they aren't intended to be used in a suitport.) So the design is also useful even when you are using a mundane airlock.

However, all conventional suits are wrong for Mars. They are too top heavy, the PLSS needs to be completely redesigned. And they are way too high maintenance even when being used in a clean vacuum. None will cope with daily use of being regularly ground against sharp dust, rocks, etc.

Offline Robotbeat

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Re: Airlocks for Mars Colony
« Reply #26 on: 01/22/2017 08:46 PM »
I bet the opposite. We'll use the suits SpaceX is developing for Mars first. SpaceX is not developing a suit port.

SpaceX is not developing a suit port for travel to ISS.

We don't know what are they developing for Mars.

IMHO suit port is much better than airlock for Mars.
Do you see a suit port suit in SpaceX's ITS video? I sure don't. I see something much more akin to the SpaceX commercial crew suits. Definitely don't see a big port on the back of them:

SpaceX's spacesuits have a major design requirement that suitports simply can't meet: they MUST look badass.
« Last Edit: 01/22/2017 08:56 PM by Robotbeat »
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Offline Coastal Ron

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Re: Airlocks for Mars Colony
« Reply #27 on: 01/22/2017 11:51 PM »
Someone above mentioned 'no free lunch'... how do you retract without pumping?  Suggest you save the balloon for something more useful.

I'm figuring that air loss is more important than power, but no doubt there is a balance to be struck.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline lamontagne

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Re: Airlocks for Mars Colony
« Reply #28 on: 01/23/2017 12:15 AM »
Someone above mentioned 'no free lunch'... how do you retract without pumping?  Suggest you save the balloon for something more useful.

I'm figuring that air loss is more important than power, but no doubt there is a balance to be struck.
Air loss is power.  Atmosphere in a Martian habitat is just a form of energy storage  :-)  It would cost about 250$ per vehicle airlock cycle to vacuum the lock atmosphere. The cost of the atmosphere, mostly oxygen and nitrogen is, perhaps about 20 or more times that value.  There is a compression page in the joined spreadsheet.  Compression or pumping are the same work.

Offline Robotbeat

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Re: Airlocks for Mars Colony
« Reply #29 on: 01/23/2017 12:22 AM »
So we can halve that cost if we halve the pressure... Just saying. :D

(Side note)
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline Nibb31

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Re: Airlocks for Mars Colony
« Reply #30 on: 01/23/2017 09:03 AM »
Remember that Mars dust has a high concentration of perchlorate salts, which are highly toxic. Fighting perchlorate contamination will be one of the toughest tasks a Mars expedition is going to be faced with.

I can see only two ways of prevent Martian dust from contaminating the atmosphere of the hab:
- Either an extensive washdown of anything coming inside, which will consume a lot of water.
- Or suit ports.

Even if suitports are used for most EVAs, there still needs to be an airlock to bring suits and equipment inside for maintenance.

Offline guckyfan

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Re: Airlocks for Mars Colony
« Reply #31 on: 01/23/2017 10:01 AM »
Even if suitports are used for most EVAs, there still needs to be an airlock to bring suits and equipment inside for maintenance.

I expect workshops for maintenance of suits and vehicles completely separate from the living quarters. Maybe with a pressurized path but separated by their own airlocks. That would reduce contamination significantly.

Offline Paul451

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Re: Airlocks for Mars Colony
« Reply #32 on: 01/23/2017 11:05 AM »
I expect workshops for maintenance of suits and vehicles completely separate from the living quarters. Maybe with a pressurized path but separated by their own airlocks. That would reduce contamination significantly.

That's what I was trying to get at with my sketch of separate chambers bracketing the airlocks. The idea that you have an outside, unpressurised by enclosed area you can do things like brush or blow dust off of vehicles, and which has a floor that is not regolith & dust. Then the airlocks. Then another area which is at habitat pressure, but is still separated from the main habitat because you assume it will end up with a lot of dust.

Since you have an area you assume is dusty, that seemed to me to be a logical place put your main machine-shop. Dust, fumes, etc, just adds to the mess. And logically, the airflow is from habitat, to low-dust workshop/prep-area, to high-dust workshop/prep-area, to air filtration plant, then to the air-conversion system (mechanical or biological), then probably through the agricultural areas, then back to the habitat.

(Edit: In my sketch, the "low-dust area" in the pressurised bay effectively serves the role of non-pressurised airlocks. Since air is always flowing in that direction.)
« Last Edit: 01/23/2017 11:09 AM by Paul451 »

Offline Robotbeat

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Re: Airlocks for Mars Colony
« Reply #33 on: 01/23/2017 11:39 AM »
Remember that Mars dust has a high concentration of perchlorate salts, which are highly toxic. Fighting perchlorate contamination will be one of the toughest tasks a Mars expedition is going to be faced with.

I can see only two ways of prevent Martian dust from contaminating the atmosphere of the hab:
- Either an extensive washdown of anything coming inside, which will consume a lot of water.
- Or suit ports.

Even if suitports are used for most EVAs, there still needs to be an airlock to bring suits and equipment inside for maintenance.
Maybe. Or maybe perchlorates are overblown.
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Offline pobermanns

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Re: Airlocks for Mars Colony
« Reply #34 on: 01/23/2017 09:42 PM »
The idea that you have an outside, unpressurised by enclosed area you can do things like brush or blow dust off of vehicles, and which has a floor that is not regolith & dust.

I like the whole scheme for incremental regions. But for the outer, unpressurized area, would it be helpful to have filtered and (slightly) pressurized ambient Martian air flow into that area, so that it would help keep any new dust from coming in?
« Last Edit: 01/23/2017 09:44 PM by pobermanns »

Offline Paul451

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Re: Airlocks for Mars Colony
« Reply #35 on: 01/23/2017 10:21 PM »
The idea that you have an outside, unpressurised by enclosed area you can do things like brush or blow dust off of vehicles, and which has a floor that is not regolith & dust.
I like the whole scheme for incremental regions. But for the outer, unpressurized area, would it be helpful to have filtered and (slightly) pressurized ambient Martian air flow into that area, so that it would help keep any new dust from coming in?

Then you either need another airlock, or continuous over-pressure. Which seems a waste. The outside area is just about creating a stable, protected prep and storage area. Based on the similar unpressurised structure on the ISS "Quest" airlock. But scaled up, in this case, for vehicles.

Offline Oersted

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Re: Airlocks for Mars Colony
« Reply #36 on: 01/24/2017 10:36 AM »
Regarding the "outside area" I think it doesn't really need to be outside the hill-side. Just let it be the first big room in the tunnel system and then have the airlock a bit further inside the hill. That way it won't be necessary to build a hall outside and expend invaluable material on unnecessary walls. It would probably also improve the airtightness of the airlocked zone that it only begins well inside the regolith.
« Last Edit: 01/24/2017 10:42 AM by Oersted »

Offline Unobscured Vision

Re: Airlocks for Mars Colony
« Reply #37 on: 01/24/2017 11:20 AM »
Are we talking a very large Hab that we've buried with regolith, or an actual "we've tunneled our way into a hillside" kind of idea? I just need some context.  ;)
Yep ... just ... yep.

Offline lamontagne

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Re: Airlocks for Mars Colony
« Reply #38 on: 01/24/2017 11:54 AM »
The idea that you have an outside, unpressurised by enclosed area you can do things like brush or blow dust off of vehicles, and which has a floor that is not regolith & dust.
I like the whole scheme for incremental regions. But for the outer, unpressurized area, would it be helpful to have filtered and (slightly) pressurized ambient Martian air flow into that area, so that it would help keep any new dust from coming in?

Then you either need another airlock, or continuous over-pressure. Which seems a waste. The outside area is just about creating a stable, protected prep and storage area. Based on the similar unpressurised structure on the ISS "Quest" airlock. But scaled up, in this case, for vehicles.
A problem that may happen with the external structure is that it will itself become dirty and contaminated, and might create a local atmosphere that is worse than the outdoors.  That may be why I prefer the semi open version.  Or perhaps it's just obstructionism ;-)

Offline Paul451

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Re: Airlocks for Mars Colony
« Reply #39 on: 01/24/2017 07:09 PM »
Are we talking a very large Hab that we've buried with regolith, or an actual "we've tunneled our way into a hillside" kind of idea? I just need some context.

The topic came up in the Amazing Habitats thread in relation to underground/hill-tunnel habitats. But it shouldn't matter in this context. The principle applies to any airlock, suitport, vehicle docking port, or storage area.

The ISS has such an unpressurised but enclosed room outside the Quest module's airlock, enabling mission preparation, with an umbilical to extend PLSS lifespan. (I don't know whether it also allows PLSS recharging without necessitating passing back through the airlock, but it seems like a logical addition.)

Hence, even for a limited flag'n'footprints mission, having an unpressurised enclosed area outside the airlock makes sense. (It doesn't have to be big, the Quest extension seems to only fit one astronaut at a time (or at least I can't find images with two.)) Even suitlock proposals typically have a closable soft-cover. But for a permanent colony, the possible secondary uses make me think it would be better to make it as large as reasonably possible.

[edit: apparently not.]



Quest module.

Being berthed.



(The airlock-proper is the larger disc-shaped section, called the "equipment lock". The unpressurised extension is the long, narrow cylinder sticking out, called the "crew lock". Which seems backwards to me.)

Berthed.



Giving birth...





[Amusingly (or horrifyingly, depending on how much these people scare you), I noticed that this image with the flimsy outer cover on the unpressurised extension is used on... certain websites... to prove that NASA is faking the whole having-a-space-station thing. You know, coz you can't orbit a flat Earth.]

And a view inside the extension (crew lock).





Suitports enclosures.

Open. (The idea is that you close the cover before you open the back-plate and return to the vehicle.)



Concept. (Individual covers. one open, two closed.)

« Last Edit: 01/25/2017 02:51 AM by Paul451 »

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