• Context:

In this sci-fi scenario/story, they don't use an space walk Astronaut suit (because of costs), but a crappier version of an astronaut suit, cheaper and mass produced.

Due to the technological advancements, the war between troops is basically WWI style: if you get out of the trench, you die, if you stay too long in a trench, you're bombarded. And yes, they are frequently sleep deprived, tired, angry and constantly miserable.

They can remove the suit, the helmet and the body aren't connected, so they can change the suit, but due to the circumstances, they cannot take the suit for more than a few minutes (either to protect them against shrapnel or against chemical weapons). Also, I thought on the helmet having an inside carbon filter instead of focusing on air filters.

For the soldiers, they can't just take out the suit and take a bath.

So, what would be the best way to clean their bodies "on the move" and avoid diseases through months of walking on trenches?

The options I thought was having a small ozone generator that goes around the body, killing viruses, bacteria and oxidising materials, just like we use those in the real world. But ozone can be toxic, specially if thousands of soldiers use those at the same time. And I don't think that they would be capable of cleaning the building up of sweat.

I also thought on a suit inside the suit, were water and cleaning agent would circulate a bit and then be expelled. But I believe that this is too much of a waste of water, not to mention that the remain water in the body wouldn't be able to evaporate to the ambient, because there isn't an ambient. Maybe inserting a ventilation system with a filter could help? But then you need a crapton of filters...

Does a mix of both or just one of these options are good enough, or there is a way simpler method to achieve the hygienic demands of the high commanders of the army?

  • 2
    $\begingroup$ Just to check, is this also low/zero g? $\endgroup$
    – PipperChip
    Commented Aug 10, 2022 at 19:54
  • $\begingroup$ @PipperChip no, it is gravity similar to earth. $\endgroup$
    – Fulano
    Commented Aug 10, 2022 at 20:26
  • 11
    $\begingroup$ if they can take the suits off they can bathe, and they will need to otherwise they will end up with what are effectively bed sores. If your bunkers/trenches are so poorly designed the soldiers cannot take their suits off for more than few minutes then they are mostly useless since it means the soldiers are under attack even when they sleep or they don't seep and die from that. $\endgroup$
    – John
    Commented Aug 10, 2022 at 22:47
  • 3
    $\begingroup$ Two questions: 1) What level of "clean" do you want/expect? At one point you mention diseases, at another "hygienic demands of the high commanders" (which could be anything). 2) When changing suits, what keeps them from taking literally 3 extra minutes to take a quick shower? In particular since these suits are supposed to be cheap - designing and equipping every suit with a fancy cleaning system seems expensive compared to providing a simple shower in the "suit changing area" (only cold water to ensure grumpy soldiers of course). $\endgroup$
    – user91641
    Commented Aug 11, 2022 at 11:26
  • $\begingroup$ @ooak clean enough to not develop any allergic reactions. An astronaut suit costs millions of dollars, anything is cheaper than that. Something around thousands of dollars. $\endgroup$
    – Fulano
    Commented Aug 11, 2022 at 12:00

5 Answers 5


Read about good trekking shoes and thier construction. Most of them have some kind of silver, copper or bronze lining for antibacterial, anti viruses and anti fungal purpouses. Smell comes from bacteria and fungus no bacteria and fungi and no smell. Psyhologically soldier can't stand more than 2-3 days awake and in battle. If not taken back for rest then most soldiers go crazy and do something stupid like suicide. You need to rotate them giving them 2-4 days of rest for each 1 day in field. Including showers and some opposite sex assistance give You more like 2 days, not giving them showers, drugs(alcohol, smoke) and company more like 4(and riots).


Rotate troops often enough and it's a non-issue.

In a system of earthworks, the fire-trench where the action happens is only the outermost layer of a complex tiered system of trenches, bunkers, and buildings that can extend many miles in depth. One of the many functions of these works is to ensure you have some troops nearby (so they can respond to any emergencies) but not actually in the trenches.

No matter how heartless your commanders are, the fact of the matter is that troops in the trenches become less combat effective over time and need to be replaced with fresh troops in order to maintain a strong front line. While they're recuperating behind the lines, you also have time to consolidate forces, replace expended weapons, repair damaged kit, and generally get the unit back in fighting shape for their next rotation.

While troops on the front are constantly exposed to (potential) enemy action and thus need to wear their protective gear constantly, the inner lines are secure enough that you can get by with blockhouses with air filters and sandbags.

Each unit spends a certain amount of time (I recommend a week) in the fire-trenches, buttoned up 24/7. And no, it's probably not very hygienic in those conditions, but they can survive that for a week. Then they spend 1-2 weeks rotated out in the back line where they can shower, catch a hot meal, and patch up a damaged suit or faulty seal. Of course, if a major advance comes, they'll be expected to drop everything, suit up, and head into the fight, but most of the time that won't happen.


Wear the suits for weeks and then burn them

My Grandad fought in Burma in WWII. Hot, damp, full of things that bite and sting. I recall him saying they used to get smeared with anti fungals and pest repellants, put on their uniforms, and patrol the jungle for weeks. On return they would march past a bonfire, pausing to strip naked and burn every stitch they were wearing before showering off the caked on layer of congealed sweat and weeks old ointments.

Being a soldier in a hostile biome is savagely uncomfortable and gross. Your suits are mass produced and cheap. Keep the soldiers in them for as long as they can stay healthy, then bring them back, burn the suits, and send them forward again.

The reality of learning to deal with being sealed in a suit in a paste of ointments and your own excretions could make for some great storytelling.

  • $\begingroup$ Just don't repeat the US's mistakes - give your soldiers breathing protection where you're burning all these space suits. A $0.10 disposable mask is a trivial price compared to both the suit you're burning, and the cancer treatments your vets are going to be facing if you don't. $\endgroup$
    – Marsh
    Commented Aug 12, 2022 at 19:44

I doubt that in the situation that you describe

the war between troops is basically WWI style: if you get out of the trench, you die, if you stay too long in a trench, you're bombarded. And yes, they are frequently sleep deprived, tired, angry and constantly miserable.

bathing would be the least of their priorities, and not bathing would surely contribute to make them miserable.

Some bactericidal effect can be achieved with proper surface engineering of the material used to make their suit

In 2013, cicada wings were found to have a selective anti-gram-negative bactericidal effect based on their physical surface structure.[4] Mechanical deformation of the more or less rigid nanopillars found on the wing releases energy, striking and killing bacteria within minutes, hence called a mechano-bactericidal effect.

That would get rid of the smell, at least.

  • $\begingroup$ There are also chemical treatments that can be antimicrobial. pcimag.com/articles/107649-a-guide-to-antimicrobial-coatings Having some of this on the suit linings, and even undergarments, could be beneficial, as long as they aren't also irritants. Some of this could be replenished when the troops get swapped out for R&R, regular meals, or whatever. $\endgroup$ Commented Aug 11, 2022 at 17:33

Hook up to the ethanol tank

The suit and soldier in it is flushed with 80% ethanol. Residual ethanol evaporates into the air cycle within the suit and eventually is dealt with by the soldier's metabolism.

On the one hand the soldiers welcome the possibility of a little buzz. The ethanol does a good job of killing germs and carrying away sweat and grease.

On the other hand this washing ethanol is used over and over and again, for many different soldiers. New ethanol is added to make up for losses but old ethanol is not wasted. Hair and skin flakes at the bottom of the main reservoir accumulate. The whole thing is pretty nasty.

But cooooool.

  • 3
    $\begingroup$ @Fulano - no smoking during the ethanol flush. $\endgroup$
    – Willk
    Commented Aug 10, 2022 at 20:34
  • 1
    $\begingroup$ I like the flush idea, but ethanol would murder your complexion. Why not olive oil? Although I suppose the scraping step wouldn’t really work. $\endgroup$
    – Ottie
    Commented Aug 10, 2022 at 22:16
  • 4
    $\begingroup$ Ethanol is a skin irritant. If it makes its way into the breathed air, it will actually intoxicate the soldiers. Also, ethanol logistics, refill equipment, the additional layer to keep the ethanol on the skin instead of everywhere in the suit and possibly even a circulatory system is adding to the cost. $\endgroup$
    – toolforger
    Commented Aug 11, 2022 at 10:23
  • 5
    $\begingroup$ "A little buzz"? A full body flush in ethanol will make your soldiers flat out drunk out of their minds very quickly (far more quickly than simply drinking it), and probably not very effective as soldiers. $\endgroup$ Commented Aug 11, 2022 at 17:11
  • 3
    $\begingroup$ I think it would make more sense if this was disinfectant. The ones you find in ambulances and hospitals leave a fat film after evaporating, so it doesn't dehydrate the skin too much (which ironically could lead to viral and bacterial infections). You could also come up with some sci-fi fantasy fluid that actually also provides other positive effects $\endgroup$
    – Neuron
    Commented Aug 11, 2022 at 17:41

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