Half a croissant, on a plate, with a sign in front of it saying '50c'
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0-Gee Toilet

Compact way to employ the centrifugal effect
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(+2, -1)
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Different cultures have different ways of dealing with the elimination of solid body wastes. "Western" cultures invented a specific "sit down" toilet system for accommodating the task, while at least some "Eastern" cultures merely expanded upon the classic-for-all "chamber pot" system (the pot connects to the sewer line). A squatting position is employed when using a chamber pot, not a sitting position.

Now consider that squatting position, and how scrunched- up-into-a-small space the body is. Let us imagine a kind of "drum" big enough to surround that squatting body (the person's back is against the curved wall).

In Space such a drum could be rotated to generate a centrifugal effect. It could be rotated from the outside, by a motorized roller that contacts its outer surface, with other rollers holding it in place. Some weights could be added at appropriate places on the inside of the drum, to arrange that the center-of-mass is close to the rotation axis, which makes the rotation more smooth. The weights could be adjustable, for different persons using this system. The weights could be a double-duty thing (part of the overall food-storage queue, maybe).

The drum doesn't need to rotate super-fast (perhaps once per second); it merely needs to provide an environment in which solid wastes can "fall" away from the body; there should be no risk of causing dizziness.

On the inner wall of this drum we permanently mount a special chamber pot. Before using it, we put a plastic bag into it (the special-ness of the pot lets it hold the bag in place). There should also be a roll of toilet paper handy. The user would adjust the weights and install the bag and check the roll for sufficient paper, first of all, of course.

So now the needy person gets into a squatting position, moves sideways into the drum, pulls a curtain over the opening, and pushes a button to begin the drum's rotation. The other side of the drum is "open", but a stationary wall, part of the spacecraft, is there. The button can be located on that wall right in the center of the circular drum-opening.

Clothing is moved out of the way, and the necessary task can be performed. It should be possible for this system to accommodate either type of body waste, regardless of the sex of the person using it.

The edges of the plastic bag can be pulled from the chamber pot, and the bag can be sealed. Clothing is re- adjusted and the button on the wall is pushed again -- easy to get at even while the drum rotates, because of being located in the center of that non-rotating side- wall.

The drum's rotation gradually slows to a stop. Ideally, we would want the final stop-orientation (because of location of chamber pot on inside of drum, and the relative orientation of the outside curtain) to always be the same place. The curtain is pulled aside and the person can exit, taking the bag along for final disposal or recycling-of-biomass.

Finally, for the sake of complete dynamic balance, there should be a second drum that rotates the opposite direction. The mass it rotates could also be, for example, part of the overall food-storage queue. Or maybe a water tank. It doesn't especially need to be adjustable; accelerometers can reveal the masses of both drums when rotation begins, and the rotation rates can be computer- controlled, so that both drums have equal and opposite total angular momentum.

Vernon, Sep 28 2013


ytk, Sep 28 2013

       I'm aware that the physical orientation of a body, scrunched into a drum as described, is not the best for making use of the "direction" associated with the centrifugal effect. The chamber pot may need to have a sort of butt-rest to ensure some actual "altitude" exists. Some experimentation is probably in order, to find the most workable design, within this particular rotational environment. Perhaps the chamber pot should simply be "inset" into the wall of the drum (but it must not interfere with the outer rollers, of course).
Vernon, Sep 28 2013

       So, in short, a small bathroom which is spun to provide simulated gravity?   

       I don't know how convenient (or otherwise) current zero-G loos are - I presume they use some kind of air current to make sure things go the right way?
MaxwellBuchanan, Sep 28 2013

       At least one type of 0-Gee toiletry has been described as being designed such that stuff is SUPPOSED to hit the fan. And it doesn't work well for liquid waste; it is my understanding that catheters are used for that, very uncomfortable for women.   

       I might mention that one Science Fiction story I've read suggested that folks in space simply use diapers. Seriously! Well, I do understand the logic...but I also know what my preferences are -- pseudogravity, in this case!
Vernon, Sep 28 2013

       //it is my understanding that catheters are used for that//   

       I'm pretty sure they're not.   

       Male astronauts use a relief tube (basically a funnel, with air being pulled through it to keep things moving the right way). Female astronauts use something similar - an oval shaped funnel placed over the relevant area; again, suction is applied, but there are slots at the side to maintain air flow without having the whole thing latch on like a leech.   

       All astronauts wear diapers for EVAs and in situations where they can't use a bathroom (for example, during launch) - just in case.
MaxwellBuchanan, Sep 28 2013

       If all astronauts were coprophiliacs, then they could simply eat each other's waste material as it was being produced..... (sorry - it's a horrible thought, unless of course you're a coprophiliac)
xenzag, Sep 28 2013

       If astronauts went on a zero-fiber diet then they would not need to poo.
pocmloc, Sep 28 2013

       That's pretty much the approach adopted on the Apollo missions. Low-residue diets.   

       The Space Shuttle had an acceptably efficient frefall toilet, as does the ISS. We assert that - apart from the use of artificial gravity induced by rotation - this is Baked and WKTE.   

       [Suggested-for-deletion], Prior Art.
8th of 7, Sep 28 2013

       But... but artificial gravity 'is' the novel concept. I wonder if the human body eliminates waste as efficiently without gravity helping out the old peristalsis.   


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