Fast Airlock - Form-fitting, hydraulic airlock

TwinBeam · 2004-07-30 21:49:43

This is an airlock that might allow very fast transit in and out of a Mars Hab. It's also very simple - no or few moving parts to break down, no power required, relatively easy to repair.

To leave the Hab, an explorer suits up, and opens the inner airlock door. The airlock is nearly filled with airbags - currently a bit limp since they're a bit below Hab air pressure. The explorer easily pushes into the lock, and pulls the inner door shut. The doors have an airbag fitted to press into the space behind the explorer, and into the inner airbags so that they deform and create a tight fit around the explorer, forcing most of the air out the closing door, with a final bit of air going through a one-way valve as the door closes. The door and the one-way valve are then sealed.

More than 99% of the volume of the airlock is now filled with the airbags and explorer, and the inner door is sealed - so the explorer can simply open the outer door without losing very much air. The airbags are shaped so that when the outer door opens, the explorer simply steps away from the airbags - which stay hard (but do not expand like balloons) in the low Mars air pressure.

Since different explorers will be different sizes, each would carry a CO2 inflated bag sized to fill extra space - smaller explorers just carry a bigger bag. The bag can serve double duty for carrying small volumes of tools and things in and out. Once outside, the bag can be deflated (wasting nothing but easily replaced CO2).

To re-enter, an explorer would take their deflated bag off a rack outside the door, step in and shut the outer door. Since their total volume is lower with the bag deflated, the outer door shuts and seals easily, and an air valve lets in Hab air pressure so the inner door can be opened, and leaving the bags a bit limp so the explorer can easily push into the Hab.

Since an explorer might need to come inside very quickly (e.g. due to a suit failure), between uses the inner door would be kept sealed and the lock kept at Mars pressure. That way the outer door can be opened immediately, closed behind the explorer, and Hab pressure established in seconds.

Protocol for exiting the lock would call for informing people outside, so they can do a quick suit check and halt any activities that have any chance of damaging their suit.

One issue with this - the outer door must open out, so a simple door would not be held shut by air pressure alone if the inner door seal failed and the latch/lock on the outer door failed. However, it should be possible to design a door that opens outward, but would be held shut by air pressure alone.

I considered various schemes with liquid filled air bags, that would not inflate so hard in Mars pressure - but water would not serve (vaporizes in low pressure), and you probably don't want to haul along the mass of fluid, and if it leaked it'd make a mess. If the airbags are filled with CO2, who cares if they leak (the chamber is kept at Mars pressure between uses, so they won't leak into the Hab).

MarsDog · 2004-07-31 06:33:26

Maybe airbags, in the shape of rollers, similar to the old wringer washer.
It could be power assisted.

Grypd · 2004-07-31 14:56:42

What do you propose to do to reduce dust contamination inside a hab, martian fine dust would prove to be a major health hazard and as it will likely be charged very sticky on the suits. You could i supposr run a charge in your balloons but they will need regular cleaning to fix

Rxke · 2004-07-31 15:34:21

just add an open 'tube' or extended porch of some lenghth leading to the airlock, with motion-trigger sensors. When you enter the tube, it starts blowing the dust off your suit, using compressed gas (atmospheric CO2, wich is plentiful)

A bit like a carwash, but with gas...

(EDIT)

To expand on the carwash analogy: if the dust proves too sticky to be blown away, add large rotating (soft!) bristles, made out of conducting stuff, (like the carbon-fibre antistatic brushes used to clean vinyl records, they're very soft, non abrasive and discharge static as a bonus, too...)

The combination of brushing and compressed gas should do the trick.

Dook · 2004-08-01 23:19:46

Never heard of anything like this before. Sounds to me like a good idea although I would drop the blow up balloon mounted on the pressure suit. A little air loss should be acceptable.

C M Edwards · 2004-08-02 14:34:13

Having something in the air lock to take up volume so that the air lock can be refilled quickly is a good idea. I'm not sure if the tight fit you describe is necessary or conducive to quick entry, though. (I keep picturing myself, having stood at just the wrong place during evacuation, plaintively calling "Urmphl! Urmphl!" from between the cushions of a giant inflatable couch. Won't sleep well tonight...)

This could be especially useful for large, garage-sized airlocks. One difficulty with bringing the rover in to work in shirt-sleeves is all the air that must be manipulated to do that. This scheme could eliminate a large part of that. The car wash layout could prove useful there, too.

How would you handle tool access within the open airlock?

Timeslicer · 2004-08-03 00:26:57

Rxke - the car wash is a very nice idea - it's value is clearly independent of the airlock type.

CM Edwards: my thoughts on moving things in/out of the hab were several - small amounts of tools can be carried in the inflatable bags - those bags not only allow a reduced volume on re-entry, but allow a variable volume of material to move out with the explorer.

Samples will almost certainly have to be moved in a special lock to work bays, keeping them separate from the Hab environment.

Larger parts or tools that need to move in or out might use a separate lock with airbags that actually inflate and deflate, using a cylinder/piston arrangement, or perhaps a conventional airlock with vacuum pump. But for the explorer's lock I wanted something very quick, with near zero mechanical parts to break down, that could be very quickly repaired. Explorers need to be able to move as freely as possible in and out of the Hab, for fast reaction times in the event of an emergency if nothing else.

Along the same lines, I'm hoping that exploration suits will be designed that do not require a pre-breathing decompression period. Suiting up will be tedious enough, without that.

-edit- sorry for any confusion: Timeslicer == Twinbeam

DERF · 2004-08-04 05:37:56

I do really find the idea interesting, but I have to say two things:

Is the hab "birthing" the astronaut?

and

I hope they are not claustrophobic.

Pretty interesting idea though.

TwinBeam · 2004-08-06 10:59:51

Is the hab "birthing" the astronaut? and I hope they are not claustrophobic.

Yeah, that image (and issue) occurred to me also.

The claustrophobia issue should be handled by crew selection and de-sensitization therapy/training. They're going to be cooped up in a tiny environment for many months on their way there, and enclosed in pressure suits even when outdoors, so claustrophobia had better not be an issue for them!

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#1 2004-07-30 21:49:43

Re: Fast Airlock - Form-fitting, hydraulic airlock

#2 2004-07-31 06:33:26

Re: Fast Airlock - Form-fitting, hydraulic airlock

#3 2004-07-31 14:56:42

Re: Fast Airlock - Form-fitting, hydraulic airlock

#4 2004-07-31 15:34:21

Re: Fast Airlock - Form-fitting, hydraulic airlock

#5 2004-08-01 23:19:46

Re: Fast Airlock - Form-fitting, hydraulic airlock

#6 2004-08-02 14:34:13

Re: Fast Airlock - Form-fitting, hydraulic airlock

#7 2004-08-03 00:26:57

Re: Fast Airlock - Form-fitting, hydraulic airlock

#8 2004-08-04 05:37:56

Re: Fast Airlock - Form-fitting, hydraulic airlock

#9 2004-08-06 10:59:51

Re: Fast Airlock - Form-fitting, hydraulic airlock

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