Author Topic: Airlocks for Mars Colony  (Read 12690 times)

Offline Paul451

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Re: Airlocks for Mars Colony
« Reply #40 on: 01/24/2017 07:44 PM »
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.

Being unpressurised and without significant loading from wind, the walls can the flimsy and the frame can be light. Or it can be made of sintered bricks (which are horribly porous and structurally weak), arched or domed. (Finally a dome makes sense on Mars.)

I suspect that it would use up fewer resources than "digging a sodding great hole in the rock" just for an unpressurised box. But if you are digging deep into rock for the habitat, and need to dig in a certain way before you reach suitable structural rock, then yes you might use that entry volume for the airlock extension. Although you'd still need support walls, which will be stronger (therefore more resource demanding) than a structure that's not holding up semi-consolidated regolith or weak fractured rock.

(I need a better name. Porch/veranda/etc doesn't really capture that it's enclosed. Shed/carport doesn't specify that it's attached. And then, of course, I'm suggesting another inside area which is pressurised, and that needs another name.)

A problem that may happen with the external structure is that it will itself become dirty and contaminated

The only source of permanent contamination are fluids in the vehicles and equipment. And that would affect any maintenance area.

Everything else is just regolith dust and CO₂, which are obviously present in an unenclosed area.

and might create a local atmosphere that is worse than the outdoors.

How? It's not meant to be airtight, by definition. And without wind, the air won't hold any significant quantities of dust.

It's a "shed". Except that by being on Mars, it doesn't have to handle significant winds, so it can be a very light structure. It's just a way to keep the wind-borne dust out, provide a stable floor to work on, protect against sun, provide consistent work lighting, and allow you to run conduit around the walls with at least power to vehicle recharge stations and power tools (and maybe air & water lines too). Given such an area, it also seems like the logical spot to also service equipment from outside that needs to be repaired, which gives you a protected area to do fiddly work without losing parts or getting them full of dust. And that also suggests it as an area for the storage of bulk items used outside. Like spools of steel/fibre cable, power cables, large structural elements, spare vehicle parts, down to nuts and bolts and connectors. Or anything unloaded from the incoming ships, but still waiting to be assembled/deployed.

(OTOH, IMO there's no real advantage to having stand-alone roofed area, far from the airlocks, as your main vehicle storage area. You need another vehicle or an EVA to get from the habitat airlock to the vehicle shed, and when you're done for the day, you need another vehicle or EVA to get back to the habitat again. If you want to recharge the air and water supply, or drain the waste-water, you need to transport the fluids to/from the habitat or have a secondary fluid/gas processing plant at the shed. Similarly you can't easily share power with the hab. And what does it gain?

Exception: You might have a simple sun-shade at a common off-site area that needs a lot of maintenance - such as the ISRU plant, the launch/landing pads, etc. Solar panels as the roof to allow recharging the vehicle while the crew are off EVAing. But that's only when you are using vehicles to travel to an area each day, then exiting for on-foot EVA. The vehicles return to the habitat at the end of each shift.)

Offline Paul451

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Re: Airlocks for Mars Colony
« Reply #41 on: 01/24/2017 08:25 PM »
Should this thread be moved from the SpaceX Mars section back to the general Missions To Mars (HSF) section?



Feeling a bit guilty for hijacking the thread.

So here's another airlock concept that was discussed in other threads.

The Wetlock or Moon-pool.



Image courtesy of MeekGee. (KelvinZero is another strong proponent.)

MeekGee suggests an ice-layer at the end (kept thin enough to walk or drive through, but which reduces evaporation). KelvinZero has wondered about using another liquid with a very low evaporation, or having a low-evaporation layer floating on the water. I've suggested a low pressure airlock at the outer-end, just enough pressure to reduce boil-off at the target temperature, and high enough humidity to eliminate further evaporation.

And many of us have mentioned the complication of buoyancy.

Offline Lar

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Re: Airlocks for Mars Colony
« Reply #42 on: 01/24/2017 08:31 PM »
Should this thread be moved from the SpaceX Mars section back to the general Missions To Mars (HSF) section?
Moved. Doing a report to mod is another good way to ask for same, actually better... (2 years from now when someone's coming up to speed, they won't care about this housekeeping stuff)

If there is another one that should have moved (I forget now) report to mod or PM me...
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline Ionmars

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Re: Airlocks for Mars Colony
« Reply #43 on: 01/24/2017 09:01 PM »
For the outdoor foyer to the airlock:
Maybe there is finally a practical use for an iRobot Roomba.
Or would it even work in very low air pressure? Maybe a rotary dust brush like a Bissel Sweeper, electrified.
(I know my proper role in the Earthly Martian household!) :)
« Last Edit: 01/24/2017 09:02 PM by Ionmars »
After landing, Mars pioneers will require our continued support.

Offline Jim

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Re: Airlocks for Mars Colony
« Reply #44 on: 01/25/2017 01:42 AM »

(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.)


Wrong.  The long, narrow cylinder is the "airlock".  It is the part where the crew (two of them at the same time) enters and exits the station.  It is the only part that is depressurized and repressurised, hence crew lock.   The "equipment lock" is where the EVA suits and tools are stored and maintained.  It is where the crew does there pre breathe campout.

There is no "unpressurised but enclosed room".  There is no "umbilical to extend PLSS lifespan" on the exterior.  Just like the shuttle (in fact the crew lock is based on the shuttle airlock), the crew is on umbilical until the airlock is depressurized and goes back on umbilical while the airlock is depressurized.

Two crew in the crew lock (who else would have taken the photo of one of the crew)
« Last Edit: 01/25/2017 01:50 AM by Jim »

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