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The Dark Side Of Manned Spaceflight and Rotational Gravity.... Toilets


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An otherwise professional astronaut in the early days of manned flight once said "Another $^$%# *human waste*" live to flight control back on earth. Apparently some of the waste was freed from the plastic bag and the astronauts resorted to picking it out the air with paper towels.

 

That's a worst case scenario.

 

With rotating gravity, you need two toilets, one for gravity, and one without... or do you?

Not to mention all that flushing, water is precious so I imagine if anyone has diarrhea or one too many bathroom trips the rest of the crew will start sternly looking at him/her.

 

Anyone else think of the challenges and solutions here.

The challenge is REAL people. This is serious!

 

But really.... it is. Floating human waste in your hab module is no joke....

Edited by Spacescifi
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5 hours ago, Spacescifi said:

With rotating gravity, you need two toilets, one for gravity, and one without... or do you?

Two with gravity, at the opposite ends of the rope.

5 hours ago, Spacescifi said:

Not to mention all that flushing, water is precious so I imagine if anyone has diarrhea or one too many bathroom trips the rest of the crew will start sternly looking at him/her.

No problem. Just make the bottom side open, and the space vacuum helps you.

5 hours ago, Spacescifi said:

Anyone else think of the challenges and solutions here.

Since Mercury flights? Unlikely.

Russians just liquid on the bus wheel before the flight. 'Muricans don't, so have to suffer.

5 hours ago, Spacescifi said:

Floating human waste in your hab module

Even if you are not very happy with your crew comrades, it's still not a reason to call them so.

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Well, let's look at what they've got.

The new ISS toilet certainly lacks charm:

uwms_diagram_web_feature_v3_10.jpg

The Russian one isn't much better:

Zvezda_toilet.jpg

Old (pre-2020) ISS toilet:

4_1.jpg

Much more reasonable. Although I suspect the gear-shifter and e-brake were removed to stop astronauts from making vroom vroom noises on the crapper. Joking aside, I think you could use the same general mechanism as the above for a toilet in gravity, and have it be slightly more ergonomic. Bigger hole and more comfortable seat and you should be...good to go...

 

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39 minutes ago, FleshJeb said:

Well, let's look at what they've got.

The new ISS toilet certainly lacks charm:

uwms_diagram_web_feature_v3_10.jpg

The Russian one isn't much better:

Zvezda_toilet.jpg

Old (pre-2020) ISS toilet:

4_1.jpg

Much more reasonable. Although I suspect the gear-shifter and e-brake were removed to stop astronauts from making vroom vroom noises on the crapper. Joking aside, I think you could use the same general mechanism as the above for a toilet in gravity, and have it be slightly more ergonomic. Bigger hole and more comfortable seat and you should be...good to go...

 

 

I see... so use air suction again... not water. Makes sense I suppose.

Also explains astronauts says the ISS smells like.... cleaning solution and burnt steak if I remember correctly.

 

You know what grosses me out though? Cleaning. I presume disposable wipes, but on a long mission or just living in space that may not do at all.

It's ironic really,  it turns out big scifi space stations, barring inner life support that is heavily geared toward recycling and reusuability (which is not what we see on TV)  actually would need vessels to dock regularly just to drop off disposable supllies and pick up garbage so the station won't have to deal with it.

 

Spacestations and spaceships are their own ecosystems.

Edited by Spacescifi
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1 hour ago, FleshJeb said:

4_1.jpg

"No Step"

Step?? In zero gravity???

***

Still no coffee table for newspapers and magazines. :(

 

1 hour ago, Spacescifi said:

Also explains astronauts says the ISS smells like.... cleaning solution and burnt steak

Mice. Space mice. They gnaw the wires and then smell like the burnt steak.

 

1 hour ago, Spacescifi said:

Cleaning. I presume disposable wipes, but on a long mission or just living in space that may not do at all.

As I suggested before, snow.

Fridge, fan, snow.

The snow appears from water, and melts into water. No wastes, no storage. Just recyclable water.

Also if keep the station warm, no need in clothes. Just the snow again.

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On 10/16/2021 at 8:08 PM, Spacescifi said:

With rotating gravity, you need two toilets, one for gravity, and one without... or do you?

You would only have a null-gee toilet if  the rotation would often stop or there was something preventing you from getting to the "gravity" toilet from null-gee.  Barring some great improvement, nobody would use a null-gee toilet if there was one in a rotational frame of reference.

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sounds like an engineering problem to me.  you would probibly just use the innards from a zero g toilet (assuming it can function in gravity) and reinforce the seat. 

Edited by Nuke
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6 minutes ago, kerbiloid said:

And now to the zero-g litterboxes.

this is why we need a cat centrifuge module.  cats could probibly work out in zero g, but they sure as hell wouldn't like it. 

Edited by Nuke
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You don't need water to flush a toilet - that's an invention from Victorian times and is a terrible waste of drinking water even on earth. Toilets in environments with a gravity are much easier to manage than in microgravity.

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I was thinking of the many types of dry toilet that exist, most notably compost toilets but also incinerating toilets and others. But if you only need to get rid of the product and don't need the compost value/water content, just collecting it in a bag and dumping it also works.

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anything that can be craped can be burned of you dry it first, thus reclaiming the water in the process. also crap can be mixed with mud for making bricks or for plastering various constructions. probibly not useful on a space station unless it was a huge tourus or oneil cylendar with a lot of land area. perhaps more useful in planetary colonization. i can imagining traveling millions of miles  to live in an adobe hut an mars. i wonder if crap is an effective sealant.

a more environmentally friendly approach is to use gray water for toilet flushing.  with the amount of gray water that gets wasted, the 1.5 gpf doesnt seem like that much. just run the water feed from a tank placed above the toilet to the toilet and gravity will handle the tank refils, all you have to do is pump filtered gray water into the tank from various sources. usually its as simple as putting the plug in the tub before a shower and then pump it to top off the tank. your morning shower alone could probibly handle a days worth of flushing. feeding it waste water from laundry or other appliances. a bigger tank means you can save even more water by reducing showers or laundry. i think the biggest issue might be the various detergents coming off of appliances, and gray water from showers is likely going to have a problem with soap scum buildup on the tank that might cause problems down the line. so you will probibly need additives and filtering to keep the gray water as clean as possible while controlling bacterial growth. we actually throw out quite a bit of water for the sake of hygiene, sometimes to the point of excess. 

Edited by Nuke
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On 10/18/2021 at 12:53 PM, Deddly said:

I was thinking of the many types of dry toilet that exist, most notably compost toilets but also incinerating toilets and others. But if you only need to get rid of the product and don't need the compost value/water content, just collecting it in a bag and dumping it also works.

im still a proponent of outhouses. not a common urban appliance except the plastic port-o-potties you see at construction sites and sports events. no im talking that little wooden 4x4 shack out in the middle of the field. dig a hole, drop a section of plastic culvert with perforations in the bottom end (we just used a spade bit) and fill in around it with dirt. then you drag your shack over it. every few years you have to start a new hole, you move the shack to the new tube, line it up with the toilet seat, and just fill in the other one with dirt and the culvert just stays in. buried plastic is effective carbon sequestration (though you can build a wooden box if you want something biodegradable, just make sure you replace the hole before the wood rots). its a good trade off between environmentally friendly and sanitary. 

Edited by Nuke
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1 hour ago, Deddly said:

@Nuke A similar idea can be found all over the Swedish countryside. Done right, they are excellent solutions. On a space station is more difficult :sticktongue:

in space, crap is a much more valuable resource.

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1 hour ago, Nuke said:

in space, crap is a much more valuable resource.

Interestingly, in some countries, companies used to have workers go from door to door buying people's "night soil". It should be a valuable resource down here as well but nobody gives a crap. 

Edited by Deddly
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@Nuke, @Deddly

I'll offer some perspectives from the civil engineering end. I also spent over a decade working for a firm specializing in designing septic systems for highly-constrained sites.

1) I wouldn't make structural brick out of dried poop. I don't know what the materials strength might be, but I suspect it's much weaker than clay. Organic material is also a big no-no in construction, unless it's been effectively "fossilized" by mixing it with quicklime. In most cases, it's limited to a small percentage of straw (for tensile strength), mixed with clay. Organics decay and lose volume, causing structural failures. For road-building, we specify that no more than 3% by volume of organics is allowed.

2) Wastewater treatment is a fun subject. I'll generally agree that we are excessively hygenic, but too many people in history have died of cholera, et al to not take treating wastewater very seriously. The issue with outhouses is that they over-concentrate waste, and don't offer full treatment of pathogens. Primary treatment is a septic tank, which through a selection of baffles and retention time separates out fats, soap, and the solid waste (poop). The volume of poop is greatly reduced by anaerobic microbes (present in the environment and your body) and turned into microbe bodies and gases. Viruses and dangerous bacteria can easily survive this process. Which is why we do Secondary treatment and disperse that water into the soil over a large area. This is an aerobic process, made possible by microbes naturally present in the soil. The soil microbes and oxygen present in the pores of the soil eat or disassemble the remaining pathogens coming out of the septic tank. In a properly designed septic system in ideal soil (a high proportion of small pores), the wastewater effluent is considered non-pathogenic after travelling as little as 2 feet though native soil. Unfortunately soil is rarely perfect, and there are many opportunities for shortcuts as the water disperses, so the accepted setback from septic tanks and leachfields to a water source (wells, streams) is 100 feet. There is also the the issue of high concentrations of nitrogen and phosphorus in the wastewater, and those take a bit more distance to get used up than the pathogens. (High concentrations of nutrients are really bad for waterways, causing microbial and algal blooms and sucking all the oxygen out of the water). All this considered, picking a good site for for an outhouse, and constructing it properly can be harder than it looks. An outhouse provides a highly concentrated point-source of pathogens and nutrients. Fun fact that most people don't know: Water flows through soil 10x faster horizontally than it does vertically. Not to mention, in most locations the functionally impermeable layer of subsoil is more shallow than you think. The groundwater during the wet season might be VERY shallow. This will easily lead to polluted groundwater popping out of the soil downhill of the outhouse, and is a disease-bomb waiting to happen.

EDIT: I forgot to mention that septic systems form slimy "biomats" in the leachfield trenches. In an overloaded (overconcentrated) system, the mat gets thicker over time, and prevents the wastewater from flowing through the soil, causing it to pop out of the surface before it's properly treated.

Where this applies to spaceflight is that you might find an aquaponics or hydroponics facility onboard a large spaceship or in an offworld colony. Use those nutrients to grow food, right? First and foremost, it's a wastewater treatment system, and it has to be very good to not put pathogens in your vegetables or your fish. Which is why you also want to include Tertiary treatment. On earth, this involves using disinfectants such as chlorine, ozone, UV light, or heat to make sure absolutely everything dangerous is dead. Any terrestrial wastewater treatment plant should be doing tertiary treatment before discharging into a waterway.

3) In most of the jurisdictions I've designed in, "gray" water is treated the same as "black" water (poop). A lot of pathogens come off the body when bathing.

4) Crap is also a valuable resource on Earth. Unfortunately we tend to mix it with soaps and bleaches, as well as "sewerable" industrial waste.

Apologies for the novel--I love the subject, and the vast majority of people don't think about how much rigorous study and empirical testing has been done.

Edited by FleshJeb
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