It feels a hell of a lot like the multimillion dollar pen vs the pencil myth - it costs them maybe $20K to send six months worth of clothes to the ISS per astronaut on a Dragon 2. The ISS-rated dry cleaning machine would cost at the very least a million dollars to develop, would still require sending ten grand of fresh solvent every so often (maybe once a year?) and would add new fire/explosion safety concerns, which they can and do put a price tag on. It would probably take longer than the life of the station for the ISS dry cleaning machine to pay itself off.It's just too easy to not bother. For a moon colony or a Mars base, the economics change, but for near earth orbit it just doesn't make sense.
jessriedel|5 years ago
Maybe true now, but this wasn't the case when this 2003 NASA article was written. It quotes >$5k/lbs for the Shuttle. Six months of clothes for a single person wearing each article for a week is still going to run, what, at least 40lbs, or >$200k. With six people on the ISS, that's at least few million bucks per year, and likely more. The ISS must have been planned to last minimum 10 years (without anything cheap like Dragon on the horizon), so I think it's still a valid question why they didn't design a small washing machine.
montagg|5 years ago
Not actually advocating for that—beyond cultural difficulties, I’m pretty sure clothes are useful enough to maintain—but it’s an interesting thought exercise to zoom out from “how to wash clothes better” to “how to do the job clothes do better with minimal cost.”
nine_k|5 years ago
The second thing is individual thermal comfort. Say, 20°C is usually "fine for everyone", but some people would feel that it's quite warm to wear a T-shirt, while other people would find it barely warm enough to not wear a coat.