Just a weird question that popped in my head, but since the only real space station in existence always keeps itself squeaky clean, I wonder how one that doesn't have cleanliness as high priority would look? In everyday life, the dirty and gritty look we are used to are influenced, if not created, by gravity. Obviously dusts fall down, but rusts and stains also forms on places that gathers water, which of course is influenced by gravity. In spacecrafts where there is no gravity to pull things, and no system to clean the air, where would the dirty stuff go?

Edit: to put in more context, I was thinking about near-future setting without sci-fi artificial gravity, where interplanetary space travel has become common and inevitably someone is going to have lower hygiene standards for their space travels (not necessarily not having air circulation system; some of the comments have pointed out that living in space basically impossible without it). And this question mentions space station, but I suppose spaceships can also be included.

So my question really is, if I want to a portray dirty, old, weathered, and badly maintained spacecraft without artificial gravity, how would I do that? Which places would get dirty, by what, and how? And how much can you get away with leaving things dirty until it starts to become serious health hazard?

  • 6
    $\begingroup$ Into your lungs $\endgroup$
    – DKNguyen
    Commented May 22, 2021 at 5:07
  • $\begingroup$ Why would it 'go' anywhere? You could tell us about the automated systems circulating air, or if there aren't any, then the air isn't circulating and nothing goes anywhere. Slight gravitational attraction towards the center of mass, probably overcome by simple thermal motion of air molecules. Nothing really happens. Impossible to say without more context. Where's the worldbuilding problem to solve here? $\endgroup$ Commented May 22, 2021 at 6:35
  • 1
    $\begingroup$ Without air systems circulating the air, gasses don't rotate and people suffocate in their sleep. Oxygen isn't distributed, and environmental poisons build up rapidly. So no space station can let the air system get 'dirty' or everyone dies rapidly. $\endgroup$
    – DWKraus
    Commented May 22, 2021 at 11:22
  • 5
    $\begingroup$ Hollywood has a conception of HVAC equipment that crosses the boundary into worship. The slowest fan will pulverize a video game character that can withstand rocket launcher hits, and of course every ventilation shaft used to infiltrate a building is spotless, as if polished by an army of diligent servants. Nonetheless ... in the real world, the inside of a ventilation shaft is not a pretty thing. Dust can most definitely stick to things without gravity - anyone dusting a shelf knows that there is more involved than just lightly blowing on it! $\endgroup$ Commented May 22, 2021 at 12:02
  • 2
    $\begingroup$ Worth looking out for descriptions of Mir towards the end of its life: real problems with mould, for example. In their case it was mostly in inaccessible and hard-to-clean locations (inside vents, behind panels) but I can easily imagine somewhere less intensively maintained getting a speckling of mould on all the surfaces. Not a pleasant thought. $\endgroup$ Commented May 22, 2021 at 20:23

2 Answers 2


Seems likely that under those conditions that electrical attraction and air-flow would dominate.

Kind of like how on Earth computers are absolutely great dust collectors.

However, indeed, anything that isn't picked up by static-charged surfaces or air-filters is likely to end up in people's lungs.


It's difficult that you will get rust in a space station, because usually lighter alloys than steel are used for space application, like aluminum, which does not rust.

Said that, it has happened in the past that some space missions have become a mess: notoriously, one of the first NASA astronauts to experience space sickness ended up so sick that he had gastrointestinal problems, with the resulting emissions floating around in the space ship.

The astronauts did their best to clean the mess up, but they had to deal with organic particles floating around for the whole of their mission.

In another instance, if I remember correctly, an astronaut sneaked a sandwich on board, and after he ate it the crumbles remaining floating around until landing, for which he was reprimanded. (kudos to Charles Staats for the link)

This is the kind of situation you have to keep in mind.

For the odor, let's hear what astronauts have to say about their "clean" spaceships

The interior of the International Space Station smells a little more mundane. Pettit, who recently returned from a second six-month-long mission on the ISS, told SPACE.com, "[The space station] smells like half machine-shop-engine-room-laboratory, and then when you're cooking dinner and you rip open a pouch of stew or something, you can smell a little roast beef."


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .