How to sterilize the interior of a spaceship?

[InterCity]

Hello, kerbonauts.

I'm writing a story right now which has the protagonists, members of the last plague-surviving group of humans in the universe (I know, cliché) travelling through space to find themselves a new planet. The twist is that the plague (without any remedy) appears on the ship and starts wreaking havoc on the survivors. The solution to this is closing everyone into stasis tanks, hoping that the cure will be found sooner than later. But story happens, and so one of the heroes has to disinfect a large (abandoned) part of the ship without any ethanol or formaldehyde at hand. So far I was thinking it could be achieved by sealing the section, disabling the heating and climate control systems and opening the airlock for an extended period of time, say, 30 days.
I know that this should be enough (in theory) to kill any bacteria if it was open space, but the ship is enclosed and radiation shielded. I'd like to know whether the vacuum itself is enough to kill the pathogen (either bacteria or virus), or I'll need something more than that.

P.S. It is not the world's most resilient pathogen, but neither it is the weakest.

[Bill Phil]

Hmm... I'd recommend heat. Heat does wonders. Have them go near a large heat source. Idk though, it may not be sufficient.

[StrandedonEarth]

Yeah, viruses should be able to survive hard vacuum. Heat is the best, they'd need to cook the inside of the ship. The ship is radiation shielded, but a lot of radiation from inside the ship should also work.

[Hcube]

Depends on the kind of bacteria but 30days of vacuum would probably kill most of them. Big heat will kill all of them for sure though, but a fire in a spacecraft is rarely an option.

Virus will die very quickly if they do not have a host cell to live in. So 30 days in vacuum-->i wouldn't worry so much about a virus. Bacteria though.. some can be tough Edited November 17, 2015 by Hcube

[Findthepin1]

Do they need the abandoned section of the ship? I assume anything capable of taking people to a habitable world (or anything large enough to have an abandoned part) will be quite large, large enough to necessarily have been built in orbit. Ships constructed in orbit have pieces, like the ISS. Have them undock the abandoned segment of the ship on both ends of the segment, and jettison it. Then have one of them go outside and supervise the redocking of the separated halves of the rest of the ship (somebody being outside the ship gives you the opportunity for something exciting to happen).

The segment with the bugs will just drift off into space (presumably interstellar, or interplanetary at the least) and never bump into anything artificial again. There's the off chance that it'll fall onto an asteroid. If it isn't completely destroyed on occasion, it won't do anything there. Bacteria and viruses go dormant or die in vacuum.

Can you post the story when you're done? :D

EDIT: Also, heat may be a bad idea, even if it's vacuum where the heat is. Space is cold. Their ship is quite unlikely to be able to make itself cooler than the surrounding environment. It'd be made to heat itself in space. If you take a ship that only heats itself up relative to its surroundings, and you make the surroundings warmer than the interior, the ship might try to heat itself up to stay 290K above the exterior. Higher interior temperature, means higher interior pressure, which if high enough means one of the walls goes [I]pop[/I] and everyone dies. Edited November 17, 2015 by Findthepin1

[Bill Phil]

[quote name='Findthepin1']Do they need the abandoned section of the ship? I assume anything capable of taking people to a habitable world (or anything large enough to have an abandoned part) will be quite large, large enough to necessarily have been built in orbit. Ships constructed in orbit have pieces, like the ISS. Have them undock the abandoned segment of the ship on both ends of the segment, and jettison it. Then have one of them go outside and supervise the redocking of the separated halves of the rest of the ship (somebody being outside the ship gives you the opportunity for something exciting to happen).

The segment with the bugs will just drift off into space (presumably interstellar, or interplanetary at the least) and never bump into anything artificial again. There's the off chance that it'll fall onto an asteroid. If it isn't completely destroyed on occasion, it won't do anything there. Bacteria and viruses go dormant or die in vacuum.

Can you post the story when you're done? :D

EDIT: Also, heat may be a bad idea, even if it's vacuum where the heat is. Space is cold. Their ship is quite unlikely to be able to make itself cooler than the surrounding environment. It'd be made to heat itself in space. If you take a ship that only heats itself up relative to its surroundings, and you make the surroundings warmer than the interior, the ship might try to heat itself up to stay 290K above the exterior. Higher interior temperature, means higher interior pressure, which if high enough means one of the walls goes [I]pop[/I] and everyone dies.[/QUOTE]
If you made it a vacuum, and then heated it up, the pathogen would get heated. Along with everything else of course. But, then you could vent more air through it to cool it down... Idk.

[PB666]

[quote name='StrandedonEarth']Yeah, viruses should be able to survive hard vacuum. Heat is the best, they'd need to cook the inside of the ship. The ship is radiation shielded, but a lot of radiation from inside the ship should also work.[/QUOTE]

Go to within 50 million kilometers of the sun, open the airlock then point the airlock at the sun. Wait.
Have the ship pass through the suns corona.

Less radical, Sterilization with formaldehyde gas (reacts with any amino groups).
How, remove most of the air, flood the compartment with formaldehyde gas and pressurize the space with water saturated air, wait and then evacuate, on refill scrub the air with GAC.

[softweir]

What sort of plague? "The" plague is due to Yersinia pestis. This is a rather fragile bacterium which is unable to survive long outside of a host. - it can't be spread by cough and sneezes, but must be transmitted blood-to-blood by a vector such as fleas and mites. All you have to do to get rid of that is kill the host animals (pet rabbits, rats etc) and treat the human victims with antibiotics. Any remaining vectors such as fleas can be killed by dialling down oxygen levels for a few days.

If you assume it is a tougher bacterium than that, then many will be killed by boosting oxygen levels. While aerobic bacteria are able to survive normal concentrations of oxygen, if you push the levels up too high then it defeats their antioxidant mechanisms a they will die of oxidative destruction of their essential molecules. It would help to push the humidity controls up as well to ensure that any bacteria remain in an active state (which makes them more susceptible), and the humidity will also help the oxygen dissolve into any biofilms the bacteria may be growing in.

(Gut bacteria in humans survive oxygen saturation treatment because the gut is such a heavily anaerobic environment.)

Of course, too much oxygen will increase the risk of fire, so it would be well for the hero to shut down all equipment in the affected section beforehand and allow the temperature to drop. You would have to make it clear that there were no oxygen-sensitive materials in that section - some substances will ignite spontaneously at high oxygen concentrations, but need a spark or similar to ignite them at low concentrations. Cheap aluminium foil has been known to ignite in pure oxygen with no evident source of ignition!

[fredinno]

[quote name='softweir']What sort of plague? "The" plague is due to Yersinia pestis. This is a rather fragile bacterium which is unable to survive long outside of a host. - it can't be spread by cough and sneezes, but must be transmitted blood-to-blood by a vector such as fleas and mites. All you have to do to get rid of that is kill the host animals (pet rabbits, rats etc) and treat the human victims with antibiotics. Any remaining vectors such as fleas can be killed by dialling down oxygen levels for a few days.

If you assume it is a tougher bacterium than that, then many will be killed by boosting oxygen levels. While aerobic bacteria are able to survive normal concentrations of oxygen, if you push the levels up too high then it defeats their antioxidant mechanisms a they will die of oxidative destruction of their essential molecules. It would help to push the humidity controls up as well to ensure that any bacteria remain in an active state (which makes them more susceptible), and the humidity will also help the oxygen dissolve into any biofilms the bacteria may be growing in.

(Gut bacteria in humans survive oxygen saturation treatment because the gut is such a heavily anaerobic environment.)

Of course, too much oxygen will increase the risk of fire, so it would be well for the hero to shut down all equipment in the affected section beforehand and allow the temperature to drop. You would have to make it clear that there were no oxygen-sensitive materials in that section - some substances will ignite spontaneously at high oxygen concentrations, but need a spark or similar to ignite them at low concentrations. Cheap aluminium foil has been known to ignite in pure oxygen with no evident source of ignition![/QUOTE]
Yeah, I think OP needs to be more specific on the kind of disease.

[NuclearNut]

Does the ship have a nuclear reactor onboard or do the shuttles/ships nearby have nuclear reactors?

If that is the case, evacuate the crew and then transport a couple of fuel elements around the ship using a robotic probe and watch as everything dies from radiation exposure. If you want more drama, have them jury-rig a system to do the transporting of the spent(ish) fuel elements throughout the ship.

[COLOR="silver"][SIZE=1]- - - Updated - - -[/SIZE][/COLOR]

This will kill everything (and I mean everything) you expose it to, well excepting possibly some extremely radiation resistant bacteria, but if it is a virus, prion, bacterium, or anything larger, it will be dead by the time you put it in the room. On the upside, this will probably (dependent on spent fuel heat production) not have any fire risk, will not involve you creating a vacuum, wasting all of your precious air, and not damage anything non-biological. Of course it will yellow most paper, probably ruin quite a few paintings exposed, and is you know, a spent fuel rod that will be just floating throughout the crew areas in the aft, meaning you will need a robot or something to move the spent fuel rods about for sterilization. Not to mention reactor shutdown and de-fueling procedures.

However, if you have any spent fuel lying around because your reactor has already had one fuel loading during the trip, you can just use those much easier.

[Dispatcher]

Besides vacuum exposure, how about hosing down surfaces with chlorine bleach?

[NuclearNut]

Then corrode everything in sight and damage every last bit of electronic equipment, etc?

[Stargate525]

A UV bath of the entire compartment would be sufficient to kill a lot of bacteria. Vent the compartment in question, pull off the radiation shielding, and wait a few weeks. Should be sufficient unless your germ is an extremophile (in which case, why does it love being inside humans?)

[kerbiloid]

At least he/she/it would start with a ultraviolet disinfection with special lamps.

[RainDreamer]

Vent everything and start filling the area with all the disinfectant you can think of.

[lajoswinkler]

UVC will not work as one tiny crevice in material is enough to host bacteria in its shade. UVC is used for smaller applications where total eradication of germs, being living ones or spores, is not needed.

Ozonized oxygen or formaldehyde should be fine. Just fill the area with warm mixture and wait for a few hours. The latter is better for surfaces sensitive to oxidizers. Not even spores survive that.

[InterCity]

Thanks for the responses. It has definitely shed some light on the problem.

[quote name='Bill Phil']I'd recommend heat. Heat does wonders. Have them go near a large heat source. Idk though, it may not be sufficient.[/QUOTE]

Unfortunately, although the best solution, this is impossible. Only the fusion reactor compartment and its coolant conduits are hot enough to kill pathogens, and these are unfortunately not an option. I should have been more clear on the reason for sterilizing the large compartment - the heroes need a place where they could place people awakened from stasis into quarantine to see whether they have already been infected. For this reason, it needs to be devoid of the pathogen (so they don't get infected while in quarantine) and habitable over three days (the incubation time). But then again, I guess I just could buff the climate control system...

[quote name='Findthepin1']Do they need the abandoned section of the ship?[/QUOTE]

Yes, they need it, as explained above.

[quote name='PB666']Go to within 50 million kilometers of the sun, open the airlock then point the airlock at the sun. Wait.
Have the ship pass through the suns corona.

Less radical, Sterilization with formaldehyde gas.[/QUOTE]

Neither of this are an option. They would get a big metal box heated to insane temperatures (or full of plasma in the worst-case scenario). Formaldehyde would be really nice, but really hard to come by with the limited resources on-board.

[quote name='fredinno']Yeah, I think OP needs to be more specific on the kind of disease.[/QUOTE]

Sorry for not being specific, I wasn't quite sure then. I've decided for it to be a bacteria with airborne particles/droplet transmission. Extremely infectious, with 100% fatality rate. Early on, it causes wet cough and hypersalivation, later stages involve pulmonary fibrosis, low oxygen saturation and ultimately total organism failure due to low oxygen intake. Infects only humans, animals (and one of the heroes due to being cyborg and having air filters built into his trachea and nanobots in his blood) are immune.

[quote name='NuclearNut']Does the ship have a nuclear reactor onboard or do the shuttles/ships nearby have nuclear reactors?

If that is the case, evacuate the crew and then transport a couple of fuel elements around the ship using a robotic probe and watch as everything dies from radiation exposure. If you want more drama, have them jury-rig a system to do the transporting of the spent(ish) fuel elements throughout the ship.

[/QUOTE]

The ship is powered by a tokamak (fusion reactor), but I might just add a fission reactor for, say, making tritium and deuterium necessary for the fusion. Also, the compartments are necessary, if not crucial, so irradiating them is probably not the best idea, although I'll have the characters consider this one. It is the fastest, easiest and in short term not-so-dangerous way to deal with the problem.

[quote name='Dispatcher']Besides vacuum exposure, how about hosing down surfaces with chlorine bleach?[/QUOTE]

Corrosive. Would destroy every single piece of equipment stored in the compartment. Not good for my purposes, but great emergency solution.

[quote name='Stargate525']A UV bath of the entire compartment would be sufficient to kill a lot of bacteria. Vent the compartment in question, pull off the radiation shielding, and wait a few weeks. Should be sufficient unless your germ is an extremophile (in which case, why does it love being inside humans?)[/QUOTE]

Good point. So far the best solution for the purposes. I'm still interested in other possibilities, though, so keep on thinking :) Edited November 18, 2015 by InterCity

[peadar1987]

How about steam? Reroute your secondary coolant loop into the contaminated area and flood it with superheated steam. You shouldn't need too much of it relative to the total charge in the loop. After you're done, vent into space. The decompression will cool the area again.

[tomf]

Bacteria do vary widely in their resistance to vacuum. You could have a bateria that is killed just by cold and vaccum but equally it could take something more extreme.

XKCD recons that thousands of spores will still be viable on the voyager probes after 25 years in space exposed to plenty of radiation. [url]https://what-if.xkcd.com/117/[/url]

[KerbMav]

Flooding the space with O³ sounds good.
Turn of gravity (so water sticks to walls and cealing), get all surfaces wet and microwave the module, afterwards induce explosive decompression.
Combine UV and IR to "sun bath" and "cook" the germs simultaneously.

Keep the temperature below -40° C and let the crewmembers wear spacesuits during quarentine to lower chance of infection by any residual contaminant.
The common cold (which you do not get from being cold, that only weakens your immune system, just dress warm and drink more as you would in a very hot environment) is very rare in the arctic as the viruses cannot survive in the cold air and mucus from sneezing and coughing freezing instantly.

[KSK]

A slightly sci-fi solution but your cyborg? Is there any way those nanobots he/she is carrying can be duplicated? More importantly can they be retrieved after their disinfection mission?

[PB666]

UV only works for pathogens within a line of sight or surfaces that can reflect uv, such as stainless steel.It would not remove virus that are inside equipment panels or instrument panels or hygiene equipment.

Formaldehyde is available in space in comets. It can be made from reaction of plasma hydrogen with carbon dioxide or the oxidation of methanol all of which are found in space. Depressurrization and repressurization with formaldehyde would reach every surface. UV could also be used. A cesium source could be used for sterilization but this is only rated for microbes not small viruses, something like a tmv could survive 10 fold higher doses of radiation than a bacteria could survive.

[InterCity]

[quote name='KSK']A slightly sci-fi solution but your cyborg? Is there any way those nanobots he/she is carrying can be duplicated? More importantly can they be retrieved after their disinfection mission?[/QUOTE]

Yes, there is, and he's eager to do this. But the society is condemning this as "rejecting humanity" - and there is no way to do this without people's awareness: he'd probably get burned at a stake. As such, he's often looked at as an inferior being.

[fredinno]

[quote name='KerbMav']Flooding the space with O³ sounds good.
Turn of gravity (so water sticks to walls and cealing), get all surfaces wet and microwave the module, afterwards induce explosive decompression.
Combine UV and IR to "sun bath" and "cook" the germs simultaneously.

Keep the temperature below -40° C and let the crewmembers wear spacesuits during quarentine to lower chance of infection by any residual contaminant.
The common cold (which you do not get from being cold, that only weakens your immune system, just dress warm and drink more as you would in a very hot environment) is very rare in the arctic as the viruses cannot survive in the cold air and mucus from sneezing and coughing freezing instantly.[/QUOTE]
O3 is probably too dangerous and explosive, though.

[KerikBalm]

Heat or immersion in reactive chemicals.

Bacterial spores will easily survive 30 days of vacuum
Some life can even survive complete dessication.

Enveloped viruses wouldn't last long, but those with just a protein capsid may survive.

UV light would certainly help reduce the risk- as will any mutagenic thing... While in a dessicated state, no DNA repair will be happening, mutations will build up to the point that the dessicated spore/virus is non-viable.

You can't cleanse it with fire?