Cold and Flu, are common viruses which normally infect us in the cold of winter. Ironically, those people who always keep themselves warm, stay less out-of-the-house and office, keep their windows shut, and don't venture out beyond essential travel seem the most affected.

I usually prevent those infections from exploiting temperature drops in the body by allowing myself to adjust to the gradually-declining temperatures in the fall. I do dress-up more in winter. However, I stay-out more than others, I don't dress as heavily if I stay out for a short while (An hour or less) or if temperatures are not too low. I take my cold showers year-round and I keep my room ventilated. cold showers train the body to maintain normal body temperature above that comfortable for such viruses. At this time of the year, I seem to avoid the cold and flu when people have it most.

My tendencies to have these common viruses are:

  • When I'm in the proximity of a sick person.

  • When the spring temperatures swing wildly and I cannot find a comfortable level of protection without sweating too much while facing a cold breeze.

  • When I'm well dressed, but keep getting cold air on my face. Think of standing under the A/C in summer as an example. That's my #1 reason to avoid sitting beside an A/C vent. Different body parts are exposed to different temperatures and body thermoregulation is more challenging. The virus exploits colder body parts as its backdoor entry into the body.

For the purpose of discussing enclosed space habitats, let's take-out the 2nd and 3rd option, and deal only with the first one. You may also deal with the A/C scenario in the third case.

Assume the space colony is enclosed and air is recycled, i.e. the outside conditions mandate it. Orbital space-colonies have the same problem and have to deal with hygiene challenges as well. All habitats, whether in orbit or on the surface of a planet, have contact with the outside world and accept many visitors, therefore increasing chances to introduce a sick person on board.

EDIT: A space colony may have the population of a small village. Assume the range of people sharing the inner space starts-out with 50 individuals. They take part in physically building the colony before introducing a breathable atmosphere into the system. The colony may be large enough to accommodate 200 people and an extra space for 50 visitors at any time. Space travel has just begun to become popular, so square-foot per person is limited. There's just over 200 square feet average for an individual or a small family for comfort, sleep and hygiene, and a self-service lunch room is shared with others. The square-footage for space stations in orbit may be down to 100 square feet to mostly singles and young couples.

Given these unfavorable (for us) conditions, the common viruses have a year-round amiable conditions needed to spread, and recycled air's quality is not quite the same as that of fresh air. Is that a chance for common viruses to attack more often? to develop into more violent strains, such as pneumonia or worse?

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    $\begingroup$ How large are these colonies? The more people there are, the more chance there is of an infection spreading and the harder it is to control. $\endgroup$ – Liam Morris Apr 23 at 9:07
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    $\begingroup$ Are you unaware that air temperature has nothing to do with spreading disease? The premise layed out here is a bit strange. Colds are communicated by germs. Taking cold showers does absolutely nothing to help you in any way, except making you miserable for a while... $\endgroup$ – only_pro Apr 23 at 16:58
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    $\begingroup$ @Alexander Sure, but it's not significant enough of a difference to matter. People tend to get lost in the weeds regarding this. It doesn't matter what you wear or how cold it is. It matters whether germs are being introduced to your body. When I'm well dressed, but keep getting cold air on my face is completely absurd. It's not because the air is cold, it's probably because it contains germs because it's coming from ventilation. $\endgroup$ – only_pro Apr 23 at 17:16
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    $\begingroup$ @Alexander There are, but not in any significant quantity to matter. My point is that OP seems to think temperature is the most important factor, when it's definitely not. In fact, it hardly matters at all. OP probably doesn't get colds very often due to having a better than average immune system. We're all different. Attributing this to the reasons listed in this question is just silly. $\endgroup$ – only_pro Apr 23 at 17:21
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    $\begingroup$ @Alexander Yes, but that's due to other factors associated with cold weather rather than the cold weather itself. Again, my point is that OP seems to think the cold itself is the problem, when that's just a silly old wives' tale. $\endgroup$ – only_pro Apr 23 at 17:24

Whilst an enclosed area, by its very nature, is more likely to allow for the spread of diseases, this does not mean your colony is more likely to become infected. Below are some ways your colony may be able to combat the spread of diseases or infections.


In order to prevent the colonists from getting sick, we can quarantine visitors like we do with astronauts. By having this quarantine period, and ensuring they pass a medical examination, this ensures astronauts do not go into space sick and risk infecting the crew.

Having visitors to the colony quarantined may even be essential to the survival of the colony. If a visitor had an infectious disease and spread it to the colonists, the colonists would not be adapted to deal with it. This is similar to how smallpox killed a number of Native Americans, whilst the Europeans had adapted to resist it, the Native Americans had never encountered it before.

Recycling the air may actually cause there to be less infections. You could simply have antibacterial/ antiviral filters* in the air system which would purify the air significantly. The same goes for water supplies, though it may just be easier to boil the water and distill it. In regards to your A/C infections, I think that may be because the A/C unit is sucking in air from outside which contains cold or flu viruses. By sitting next to it, you would be getting hit directly in the face with these viruses, causing them to infect you. Having a filter of some description could prevent that.

*note that by filter I mean anything that could ‘kill’ bacteria or viruses. This may be in the form of some kind of barrier with alcohol on it or intense heat that would cause them to denature. You may also use high intensity Ultra Violet light to kill off the viruses and bacteria.

The Quarian

You may want to look into the Quarian from the Mass Effect series. These are aliens who have particularly weak immune systems so, to compensate, live their lives in environmental suits. They live in a nomadic fleet of ships, when one ship becomes infected, part of it or the entire ship can be quarantined. Either a section of it can be sealed off using airlocks or shuttles to the quarantined ship can be restricted to only food and medical supplies, preventing visitors or occupants from returning until the quarantine ends.

Applying this to your question, you may have several space stations which share the same orbit (or several colonies on a planet’s surface). Transportation between these could be reduced in case of an infection, reducing the spread, or sections could be isolated to control the infection. Airlocks can be decontaminated by using UV light, heat, chemicals or by removing O2 (either by filling the chamber up with a different gas or, if the airlock is leads into space, you can just expose pathogens to the vacuum of space).

If you wanted to expand your colony, you could either build more stations or your could build more sections onto an existing one. For a real world comparison, its like the difference between building more apartment complexes or making one that's already been built bigger.

In short, whilst your space colonists are more likely to be infected due to being in enclosed environments, quarantine and life in environmental suits could significantly reduce the chances for infection. With only 50 visitors at any one time, quarantine should be relatively easy to manage. If you wanted your colonists to be infected however, you can simply say that some of the quarantine measures I mentioned were not in place or failed to control the spread.

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    $\begingroup$ high intensity UV light can also kill germs. This is used more commonly in water filtration but no reason that it can't for air (other than the incidental ozon generation). $\endgroup$ – ratchet freak Apr 23 at 9:51
  • $\begingroup$ The question is not about how to combat the diseases. I think your answer misses the point. $\endgroup$ – Argemione Apr 23 at 10:08
  • $\begingroup$ @Argemione The question is asking if a colony in space is more likely to become infected due to being in an enclosed environment. The answer is no, it is not, as there are ways to prevent the spread of diseases. Admittedly i might not have directly answered the question but i feel my answer is still valid. Regardless, i will edit it and give that direct answer. $\endgroup$ – Liam Morris Apr 23 at 10:24
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    $\begingroup$ I was also thinking of UV light in the air filtration system. Ozone is another choice (you can do both). Ozone is also common for treating water. Since water is recycled too, it's important to kill stuff that may be in it. $\endgroup$ – Cyn Apr 23 at 14:32

Flu infects us in winter for two reasons:

The flu virus is especially good at going through dry and cold air. During winter, we spend more time indoor, where it is warmer - but it doesn't really protect us because air is drier there.

The flu virus is passed via short range interactions between humans (contacts, respiratory droplets). Spending more time indoor results in people being physically close to eachothers more often.

For these reasons, an enclosed space colony is indeed a place where flu would thrive (given that there are many visitors).

"Quality" of the air doesn't matter, only humidity. (Humidifiers would slow the spread of the virus.) Then, maintain good hygien, sleep, and nutrition.

Speaking about more violent strains, viral pneunomia is usually mild. However, if you face a big epidemic, I guess you may have some serious cases.


Common viral infections only survive in the modern world because they can't infect everyone simultaneously, any virus that ever did would go extinct when our immune systems worked out how to kill it off or it killed us. The continued success of the common cold is based in it's ability to mutate between infections of a given individual, and of wider populations, cold and flu strains need time to change between infection cycles because human viral immunity is long lasting once established. In this way small, sealed, stations where everyone is exposed to any new virus almost instantly probably won't suffer continued infection from airborne pathogens after the first round of illness.

Having said that a station that receives regular visitors from a more diverse disease environment, like the Earth, will suffer repeated epidemics as new pathogens are constantly being introduced by the tourists. The station is an almost ideal environment for spreading an airborne virus due to the close physical proximity of the population and shared, low humidity, air.

Larger stations, those big enough to have physically disparate populations, (especially in terms of having a non-integrated air supply system) could develop more natural disease environments with strains mixing and spreading slowly through the station as people move around for work or leisure.


The other comments are all helpful, but to answer the questions directly...

Is that a chance for common viruses to attack more often?

Yes, I think that due to both the cycle of visitors and the limited space, you would naturally see an increase in the number of viruses that people might be exposed to.

But I think that with air filtration and quarantines the risk would be greatly reduced. Also, given that this is futuristic, you might expect much better detection of viruses, so that perhaps visitors enroute to the colony might be scanned and then turned away or quarantined before they can arrive and spread their illness.

...to develop into more violent strains, such as pneumonia or worse?

I think that due to the aforementioned ways to reduce the spread of virii, and the smaller population, I think there would be less chance for them to mutate into more violent strains.


A space ship, space station, or space habitat should have strict air quality control with constant monitoring and regulation. And that should include filtering viruses out of the air at one or more points in the ventilation system.

Every spacecraft would be likely to have at least one filtration point in its ventilation system, and larger space spacecraft, space stations, and space habitats are likely to have several virus filtration points in the ventilation system.

And in a large space habitat it is quite possible that each individual house, apartment, or bedroom will also have its individual virus filter to remove all viruses from incoming air, and possibly another filter to remove viruses from outgoing air.


Yes and No.

And we do know, because we have something akin to a "space station" - a small, insulated group of people, living close together in a controlled environment in an hostile (deadly, actually) milieu.

It's McMurdo Base in Antarctica.

And while they cope pretty well by themselves, every once in a while new blood from the other continents debarks from planes to do research with them - and when that happens, the Crud strikes:

Crud, the - Common name for colds / flu contracted by new arrivals to the US McMurdo base. Most common with a large entry of new people bringing a large influx of fresh germs. Any germ-related illnesses in Antarctica are rare in the winter as the base personnel have either had the illnesses by then or are immune to them. The longest continuous period of my life free of colds and flu was when I was in Antarctica. Am.

So you have both possibilities: insulated community and no contacts, all well and good. Insulated community and visits now and then, and viruses will spread like wildfire.


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