How to sterilize the interior of a spaceship?

[NuclearNut]

Fire in an enclosed space tends to be bad for your health and would seriously damage everything due to expansion melting and burning.

[lajoswinkler]

[quote name='fredinno']O3 is probably too dangerous and explosive, though.[/QUOTE]

No one would consider using pure ozone, it's way too difficult to make. Ozonized oxygen/air (around w=15%) is enough. But I'd use warm formaldehyde. It precipitates proteins and thus ruins them and it's already one of the staples of sterilization techniques.

[Cirocco]

Okay, I actually work in the pharmaceutical industry where we constantly need to disinfect entire rooms to produce medicine so here's some theoretical principals and practical applications that we use in the industry. Might be of use to you. Note that this is a very long post, but there's a TLDR at the bottom.

First, a basic principle: bacteria cannot move through the air on their own. They need to attach themselves to dust particles, water droplets, etc. Therefore, if you can guarantee that the air inside your compartment is absolutely 100% particle-free (or even free of particles that are larger than the bacterium in question would be sufficient), then bacteria will never move significant distances away from their stationary position and wiping down every single surface with bactericide chemicals and will actually do the job.

Note though that this means absolutely every single square micrometer needs to be wiped down and allowed sufficient time for the chemical agent to kill the micro-organisms. This is a very, very easy thing to screw up if done by humans and it's why we don't accept this method in the industry as being sufficient. But if you have nothing else to go for, this would be an option. A very risky one, but an option.

So how would we go about this? Keeping the air particle-free is usually done through the use of HEPA air filters (HEPA stands for High Efficiency Particle Arrestance). These are basically just extremely fine filters. If your spaceship has a microbiological R&D facility or any facility that requires dust-free air, then your ship will have these HEPA filters on board. In fact, it is highly likely that the central computer core would have these filters as well since dust particles and very fine electronics do not mix at all.
Redirect airflow from whatever facility normally receives the clean air to the chosen compartment, have the air pump work overtime and you should be able to clear out the air completely after a few hours.

After the air is cleaned, you need to kill any bacteria left on the surfaces. If your plague is caused by a bacterium, then there's quite a few chemicals that will kill it. High concentrations of alcohol can kill most bacteria. In fact, highly concentrated Iso-propyl-alcohol (IPA in the industry jargon) is used very often as a disinfectant. Theoretically, you could distill down booze to highly concentrated ethanol and use that. Though you'd need a LOT of booze.

Second on the list of most commonly used disinfectants: H2O2, also known as hydrogen peroxide. Highly reactive, it is also found in many industrial cleaning/bleaching solutions. The main method of disinfecting an entire area in the pharmaceutical industry is called dry-fogging. It basically means we flood the entire area in a hydrogen peroxide mist, leave it to do its thing for about 4 hours and then vent the stuff by flushing the air in the room with the aforementioned HEPA filters and air pumps. Kills everything biological, with the caveat that you NEVER expose any surface that was hidden or sealed while the dry-fogging was going on. Screws are a prime example of this. If you EVER unscrew a single screw in a sterile room you've breached sterility because the surface of the screw that was embedded could have micro-organisms on it that were not exposed to the dry-fog.
Now, the difficulty wit this is that highly concentrated hydrogen peroxide solutions are difficult to obtain, but there may be a way to get one in your scenario. H2O2 is sometimes used in waste-water treatment to remove organic impurities. Seeing as you are on a spaceship, there will more than likely be some sort of water-recycling plant. If your intrepid heroes can extract a vat of highly concentrated H2O2 from its stockpile (and it would be highly concentrated. Packing low concentrations makes no sense from a logistical point of view), then they're in business. Just take that vat, heat it to the boiling point and voila: instant Hydrogen peroxide mist.

Other methods we use to sterilize equipment, but never for full rooms include: high-energy radiation (usually gamma rays, but not practical for large rooms and bacteria could survive in the "shadow" of large objects), superheated steam (you're looking at 20 minutes over 120°C, not practical in large rooms), dry heat (well over 120°C and more like half an hour to an hour if you want to be sure. Again, not practical) and chemical wipedown (not 100% guaranteed that you got every single nook and cranny)


TLDR: if you want to do it like in real life: seal a section of the ship, start pumping through sterile air for a few hours (you can use the air filter for the central computer core. Large computer rooms usually use dust-free and climate-controlled air). Then cut the airflow, flood the entire area with a hydrogen peroxide mist, let it sit for a few hours and flush with sterile air. H2O2 will also not seriously damage any electrical equipment or stainless steel if it is evacuated within a few hours. Whatever residue that remains will quickly evaporate or degrade to water and oxygen. Again though, getting a hold of a high-concentration H2O2 solution may be an issue if they can't find it ready-made somewhere.

If the mist is not an option there is the easier but riskier method of wipedown. Again: start by flushing the air in the compartment with sterile, dust-free air. Then go in either in a completely hermetically sealed suit (like, say, an EVA suit) or send in sterilized robots to wipe down every single exposed surface with highly concentrated alcohol or some other bactericide agent. Easier, but riskier and more time-consuming.

Subjecting the section to the vacuum of space for an extended period of time would also work, provided that you can flood the compartment with clean air after you do so. But again, I would suggest dust-free computer core air for that. Note that subjecting it to vacuum of space would kill the bacteria, but could leave toxins made by said bacteria (which is the stuff that often kills you) possibly intact. You'd still want to do a wipedown even after the vacuum treatment.

Whew, long post but I'm happy that I was able to apply my industry knowledge :)

Hope it helps.

Cirocco Edited November 19, 2015 by Cirocco

[InterCity]

[quote name='Cirocco']Okay, I actually work in the pharmaceutical industry where we constantly need to disinfect entire rooms to produce medicine so here's some theoretical principals and practical applications that we use in the industry. Might be of use to you.

*[I]One of the best walls-of-text I've ever read[/I]*

Hope it helps.
[/QUOTE]

Thank you for your response. Your post is invaluable and definitely will (at least partly) make its way into the story.
I do have a medical background as well, I work as an internal surgeon (Hope I've translated my job title well enough), but all I've ever sterilized myself are medical supplies (scalpels, clamps, tweezers...), and those are usually sterilized by heat in autoclave - and I'm not even the person whose job that is. Thus I was almost clueless about sterilizing large spaces full of equipment.
I do indeed know that bacteria don't live suspended in air on their own, but they're contained on particles and surfaces, and they often spread through little droplets released when coughing or sneezing if transmitted via air (hence the coughing and hypersalivation the pathogen causes for maximum infectivity). HEPA filters are indeed [I]the[/I] good solution, and I confess, that didn't cross my mind when thinking about it, and indeed everything you've said in that regard is true. About that H2O2, I didn't count with it in the water treatment system, but I might just as well add it for the story's sake. Thanks for the idea.
On a second thought, I was not [I]completely[/I] clueless. The operation room is indeed disinfected as well. I couldn't be sure I have a supply of Stéridine (the disinfectant we use, I only know it by brand) available in space, so I decided against including it.

Thanks again, your insight is most welcome.

[Cirocco]

[quote name='JebKerboom']Thank you for your response. Your post is invaluable and definitely will (at least partly) make its way into the story.[/QUOTE]

wheeeee! I feel all warm and fuzzy inside now :D
Serisously, this sort of stuff is a massive ego boost for me. I'll be smiling about this for a week :)

and yeah, I'm an engineer so creative problem solving (like looking for H2O2 in waste-water treatment plant) is part of my job description :) Edited November 19, 2015 by Cirocco

[lajoswinkler]

Actually concentrated ethanol (96% azeotrope @ 1 atm) is not the proper solution as it's so hypertonic and reactive towards proteins that it precipitates the gooey shell around the bacterial cell and effectively makes its own barrier. Bacterial cell can then survive because its mechanisms sense something is blocking the ion transfer and it just turns into a spore which can germinate in the future.
It's one of the reasons 70% ethanol is the historical staple of disinfection and is sold as rubbing alcohol (I have no idea why some places have isopropanol) - it penetrates the cell more easily and causes harm inside the membrane where things matter. Another reason is that it's less harmful to skin.

Hydrogen peroxide mist would be ok for places not susceptible to oxidation by it. For regular purposes and where its reactivity isn't a problem, formaldehyde (not formalin!) is a really good option.

One thing we don't have enough knowledge about are prions. There are some that are resistant to classical methods of autoclaving which is really problematic, even more knowing that there are probably lots of them we simply never detected.

[MircoMars]

I didn't take the time to read al comments, so I don't know if it was already mentioned:

the "cleanest" way to sterilise is [URL="https://en.wikipedia.org/wiki/Ultraviolet_germicidal_irradiation"]UV light[/URL]. have them flood the compartment with ultra bright short-wavelenght light. UV cleaning can also be done permanently in the airducts and water tanks.

[Cirocco]

[quote name='lajoswinkler']Actually concentrated ethanol (96% azeotrope @ 1 atm) is not the proper solution as it's so hypertonic and reactive towards proteins that it precipitates the gooey shell around the bacterial cell and effectively makes its own barrier. Bacterial cell can then survive because its mechanisms sense something is blocking the ion transfer and it just turns into a spore which can germinate in the future.
It's one of the reasons 70% ethanol is the historical staple of disinfection and is sold as rubbing alcohol (I have no idea why some places have isopropanol) - it penetrates the cell more easily and causes harm inside the membrane where things matter. Another reason is that it's less harmful to skin.[/QUOTE]

very true! I forgot to mention this in my wall of text, thanks for adding that bit. Not a clue why we use IPA instead of ethanol either. Could be a question of taxes? Ethanol is very heavily taxed (in Europe at least) unless it's denatured. That's just a guess though.

[quote name='lajoswinkler']Hydrogen peroxide mist would be ok for places not susceptible to oxidation by it. For regular purposes and where its reactivity isn't a problem, formaldehyde (not formalin!) is a really good option.[/QUOTE]

I know formaldehyde is a really good bactericide, but personally I don't like it at all and the pharmaceutical industry is also moving away from it because of its toxicity. I mean this stuff can cause burns, can be toxic when inhaled, ingested or on skin contact, and is possibly carcinogenic. Now, toxicity is all a matter of concentration of the solution: low concentrations and short, one-time exposure means a whooooole lot less toxicity. But still, the possible health hazards make it a last-ditch solution for me.

[quote name='lajoswinkler']One thing we don't have enough knowledge about are prions. There are some that are resistant to classical methods of autoclaving which is really problematic, even more knowing that there are probably lots of them we simply never detected.[/QUOTE]

true, prions are a female dog, but the OP did mention that his plague was bacterial and I assumed non-sporulating. If you want to get rid of prions I would hazard a guess that enzymatic cleaning agents may help? Again though, this is pure educated guesswork on my part. And of course once you ingest the prions you're kinda boned.

[Deadpangod3]

You could just, y'know, undock the infected module and let it dock with the sun at high velocity. :P

oh right the hero needs the module, id guess what others have said and let it bake in UV for a while.

[InterCity]

[quote name='Deadpangod3']You could just, y'know, undock the infected module and let it dock with the sun at high velocity. :P

oh right the hero needs the module, id guess what others have said and let it bake in UV for a while.[/QUOTE]

It's not a module. It's a part of a hard sci-fi ship that is welded together from prefabricated section and in shape and layout it resembles a naval ship. I've traded scientific accuracy here for more wow factor (hypercompressed material in bottom level for artificial gravity, not centrifugal forces. Please don't slam me for this one ;)). I only write this to specify what we're dealing with. More precisely, The section is the observation deck.

[lajoswinkler]

[quote name='MircoMars']I didn't take the time to read al comments, so I don't know if it was already mentioned:

the "cleanest" way to sterilise is [URL="https://en.wikipedia.org/wiki/Ultraviolet_germicidal_irradiation"]UV light[/URL]. have them flood the compartment with ultra bright short-wavelenght light. UV cleaning can also be done permanently in the airducts and water tanks.[/QUOTE]

It's just for certain applications. Germs hide in crevices, too. They can be shaded from the light, so it won't reach them.


[quote name='Cirocco']very true! I forgot to mention this in my wall of text, thanks for adding that bit. Not a clue why we use IPA instead of ethanol either. Could be a question of taxes? Ethanol is very heavily taxed (in Europe at least) unless it's denatured. That's just a guess though.[/QUOTE]

I'd say it's a good guess. Might be the remnant of the prohibition in USA? Who knows. AFAIK medicinal rubbing ethanol at my place is not denaturated. It also isn't very cheap. :D

[QUOTE]I know formaldehyde is a really good bactericide, but personally I don't like it at all and the pharmaceutical industry is also moving away from it because of its toxicity. I mean this stuff can cause burns, can be toxic when inhaled, ingested or on skin contact, and is possibly carcinogenic. Now, toxicity is all a matter of concentration of the solution: low concentrations and short, one-time exposure means a whooooole lot less toxicity. But still, the possible health hazards make it a last-ditch solution for me.[/QUOTE]

For automated applications where robots do things in isolated areas, it's fine. I'd never work with it often in a way it would cause chronic toxicity. The only times I've actually encountered it, in the form of an aqueous solution was with preserved organisms and samples in jars and that was not often. It's used when stuff needs to be preserved for a long, long time and it should not be used for preserving stuff you open relatively often. Ethanol and hermetic sealing is better.
Also formalin smells... as if it's ANGRY. :D

[QUOTE]true, prions are a female dog, but the OP did mention that his plague was bacterial and I assumed non-sporulating. If you want to get rid of prions I would hazard a guess that enzymatic cleaning agents may help? Again though, this is pure educated guesswork on my part. And of course once you ingest the prions you're kinda boned.[/QUOTE]

Yeah, I don't really know what to do with them. LOL
Probably warm enzyme bath but you never know which prion we don't know about can be resistant to which enzyme. After all, enzymes are pretty much selective molecules.

[T-Bouw]

Nothing's better than a baryon sweep of course!
Make sure the crew and pets are vacated. Baryon particles kill everything...

[Shpaget]

Ultraviolet?
Simple to administer and flood entire ship, harmless to almost every part of the ship, cheap, portable...
It requires extended exposure though, so it's not an OP plot ruining deus ex machina.

[Viragos]

If your ship has RCS there's a fair probability that the monopropellant used in that is the Hydrogen Peroxide you're looking for. A pretty common monoprop system is H2O2 over a catalyst.

[KerikBalm]

To get rid of prions... maybe just cover everything in bacterial sludge... they'll find something to digest that protein.
Also don't expect prions to be an extremely virulent plague, and gene editing could easily remove the offending protein from the population.

UV light to get rid of most stuff, followed by a chemical disinfectant, depending on how careful you need to be, you might want something that is toxic enough even in vapor form (ie formaldyhyde over ethanol).
Drench in your chemical (there are many many to choose from), evacuate fumes into the vacuum of space)

A robot witha strong beta emitter that moves the source near every crevice and such could also help.

Otherwise, I don't see why a simple bacterial plague couldn't have been stopped, especially by people with future-tech that would presumably have adapted bacteriophages as an antibiotic

While resistance to molecular antibiotics seems to evolve much faster than we can make new varieties, and we've got no good program to induce things to evolve new ones - there are many who want to use bacteriophages, which could evolve alongside the bacteria which they target.



Also... I have a hard time considering the setting hard sci-fi if the biological science behind the plague is so weak, and you've opted to basically make the floors out of black holes to get gravity instead of just a centrifuge... what does that do to the ships dry mass? the gravity gradient? what about the floors above your head falls up and you feet fall down?.... ummm.... I'd rather be in a centrifuge than your ship

[InterCity]

[quote name='KerikBalm']

Also... I have a hard time considering the setting hard sci-fi if the biological science behind the plague is so weak, and you've opted to basically make the floors out of black holes to get gravity instead of just a centrifuge... what does that do to the ships dry mass? the gravity gradient? what about the floors above your head falls up and you feet fall down?.... ummm.... I'd rather be in a centrifuge than your ship

[/QUOTE]

About the plague: Engineered lifeform. [I]Designed[/I] to be uncurable, but went out of control. Spread fast and undetected (long incubation period), so it was everywhere when cure started to be made (also, terrible neglect by the government. Our science can solve it, right? Wrong.).
As for the ship, yeah, centrifuges are way better, way more scientific and way more convenient, but loses a lot of sheer wow factor. For instance, AFAIK there is no Star Trek, Star Wars or pretty much any hard sci-fi ship that opts for centrifuges over some magical artificial gravity solution.
Indeed, the mass of the ship is exorbitant, but so is the propulsion thrust. Its TWR is still high (if you mean this).
Last, I'd also hate to find myself on that particular ship. Despotic dictatorship, rapidly spreading virulent plague and fairly low hopes (not to mention later stages, the ship is there mostly as the thing that brings our heroes to the setting. Will not write further spoilers, since the first chapter is almost complete and link will be published soon (though this might change, it's probably too much of a backstory dump.).

[RuBisCO]

Depends on the virus, a virus that is not membrane bound, that is just a non-aqueous protein over DNA or RNA, can last in a vacuum indefinitely. Good old T4 can survive a vacuum, HIV can't last seconds exposed to air. Heat above 200°C will denature any protein or nucleic acid no matter if dried out or not. Above 800°C nothing organic will survive unless it is all carbon-carbon bonds or fluid hydrogen bonds (methane) as all -O, -N, -H bounds give out below that temperature on carbon. Edited November 20, 2015 by RuBisCO

[Shpaget]

[quote name='JebKerboom']For instance, AFAIK there is no Star Trek, Star Wars or pretty much any hard sci-fi ship that opts for centrifuges over some magical artificial gravity solution. [/QUOTE]

Are you calling ST and SW hard SF? Star Wars is not even science fiction, let alone [I]hard[/I].

In any case; 2001: A Space Odyssey, Rendez-vous with Rama, Ender's Game, Babylon 5, Orphans of the Sky, Ringworld. Heck, even Halo and Moonraker.

[SomeGuy12]

I'm also going to say the spent fuel rod idea is the best one I've seen. If you only have fusion power, but it's the style that produces neutrons (deuterium/tritium, etc), you can irradiate cobalt rods to make cobalt-60, a standard way to produce a whole bunch of deadly gamma rays. Radiation sterilization via gamma rays is also one of the best ways to sterilize anything, and as nuclearnut points out, the gamma rays should leave most of the affected sectors of the ship still usable.

For bonus drama, the intense radiation could cause the robot that moves the rod around to fail...

[InterCity]

[quote name='Shpaget']Are you calling ST and SW hard SF? Star Wars is not even science fiction, let alone [I]hard[/I].

In any case; 2001: A Space Odyssey, Rendez-vous with Rama, Ender's Game, Babylon 5, Orphans of the Sky, Ringworld. Heck, even Halo and Moonraker.[/QUOTE]

Alright, sorry. I have no intention to cause a flame war, and probably my definition of sci-fi is diferrent than yours. Let's just settle with "A story from futuristic setting".

[Bill Phil]

[quote name='JebKerboom']About the plague: Engineered lifeform. [I]Designed[/I] to be uncurable, but went out of control. Spread fast and undetected (long incubation period), so it was everywhere when cure started to be made (also, terrible neglect by the government. Our science can solve it, right? Wrong.).
As for the ship, yeah, centrifuges are way better, way more scientific and way more convenient, but loses a lot of sheer wow factor. For instance, AFAIK there is no Star Trek, Star Wars or pretty much any hard sci-fi ship that opts for centrifuges over some magical artificial gravity solution.
Indeed, the mass of the ship is exorbitant, but so is the propulsion thrust. Its TWR is still high (if you mean this).
Last, I'd also hate to find myself on that particular ship. Despotic dictatorship, rapidly spreading virulent plague and fairly low hopes (not to mention later stages, the ship is there mostly as the thing that brings our heroes to the setting. Will not write further spoilers, since the first chapter is almost complete and link will be published soon (though this might change, it's probably too much of a backstory dump.).[/QUOTE]
Actually, Babylon 5 has quite a wow factor. So does the Discovery 1 in 2001.

Artificial gravity just makes the ships look and operate like sea-going ships. It's more relate-able, but it subtracts from space's distinctness.

Some space craft in sci fi depictions have no artificial gravity, resulting in the crew being too weak for Earth, or most planets/celestial bodies of large size.

[NuclearNut]

[quote name='SomeGuy12']I'm also going to say the spent fuel rod idea is the best one I've seen. If you only have fusion power, but it's the style that produces neutrons (deuterium/tritium, etc), you can irradiate cobalt rods to make cobalt-60, a standard way to produce a whole bunch of deadly gamma rays. Radiation sterilization via gamma rays is also one of the best ways to sterilize anything, and as nuclearnut points out, the gamma rays should leave most of the affected sectors of the ship still usable.

For bonus drama, the intense radiation could cause the robot that moves the rod around to fail...[/QUOTE]
Or, if you are using tritium and deuterium as fusion fuel, you will produce a ton of neutrons. That will make the sides of the reactor vessel quite radioactive, and due to the short half-life if would be quite radioactive (one of the reasons JET uses a robot to move the RV sections). Any already spent sections (spent because of enbrittlement, they are re-recyclable in around 20 years) could be taken out of storage and moved about the ship in lieu of spent fuel rods. No need to irradiate cobalt rods in the reactor (which would take several weeks anyway).

[KerikBalm]

[quote name='JebKerboom']About the plague: Engineered lifeform. [I]Designed[/I] to be uncurable, but went out of control.[/quote]
So... Handwavium.... not hard sci-fi

[quote]As for the ship, yeah, centrifuges are way better, way more scientific and way more convenient, but loses a lot of sheer wow factor.[/quote]
I think the rotating structures are cool and add to wow factor (as in ring worlds, babylon 5 earth destroyers, 2001 space oddessy, even the martian)

[quote]For instance, AFAIK there is no Star Trek, Star Wars or pretty much any hard sci-fi ship that opts for centrifuges over some magical artificial gravity solution.[/quote]
Star Trek is mostly Space fantasy, with some Sci Fi. Star wars is all Space Fantasy.


[quote]"A story from futuristic setting". [/QUOTE]
Yea... so... future fantasy.
I even get annoyed at soft-Sci-Fi being called science fiction at all. I prefer "fictional science" or "future fantasy"/"space fantasy"



I think it should be a requirement that anyone reads this site extensively:
[url]http://www.projectrho.com/public_html/rocket/prelimnotes.php[/url]
before attempting to put the "hard" label on their sci-fi (sadly though, its biological science is lacking).

FYI, designing a disease to be incurable is even less viable than designing a computer to be immune to cyber-attack, or a lock to be unpickable, or a code to be unbreakable.
No matter what you do, there will be a difference between your pathogen and its host, and that difference can be targeted... even down to the DNA sequence level.

[RainDreamer]

[quote name='KerikBalm']
FYI, designing a disease to be incurable is even less viable than designing a computer to be immune to cyber-attack, or a lock to be unpickable, or a code to be unbreakable.
No matter what you do, there will be a difference between your pathogen and its host, and that difference can be targeted... even down to the DNA sequence level.[/QUOTE]

I [I]think[/I] the "incurable" here means it kills its target so quickly that without a kind of vaccine/method of prevention, the target is as good as dead on the moment of exposure and the cure cannot be administered quickly enough in anyway, not that you cannot stop it from harming you.

And well, there scale of sci-fi hardness is a sliding scale, and there are several levels in between. Ultra hard sci-fi are barely fi, mostly sci. While soft one are just technology indistinguishable from magic. I think we are not that far into soft scifi yet with this story.

[InterCity]

[quote name='RainDreamer']
And well, there scale of sci-fi hardness is a sliding scale, and there are several levels in between. Ultra hard sci-fi are barely fi, mostly sci. While soft one are just technology indistinguishable from magic. I think we are not that far into soft scifi yet with this story.[/QUOTE]

Mea culpa. I wasn't using the correct term. It will probably sound quite ignorant, but until this day, I thought that hard sci-fi is the one less backed by facts. I didn't mean to be ignorant and I didn't mean to derail the thread, so please excuse me. Anyway, I'll try not to write a completely scientifically inaccurate story, and try to have at least a grain of truth in it. I won't touch orbital mechanics (I promise ;) ), and make the ship exit Alcubierre FTL at still quite an awesome speed, so it will need to burn retrograde in order to reach stable orbit. No lightsabers (albeit those are super cool) and no force. As for the centrifuges, I think that it's everyone's call whether it has the wow factor or not, and given where this thread is, pretty much everyone will opt for the centrifuge.
And indeed, "uncurable" meant "extremely hard to find a cure for". Dunno what is wrong with me. Sorry. Edited November 21, 2015 by InterCity