Astronauts often stay more than a year on the ISS, they produce trash like any other human. Is there like a limit that they may produce ever day or maybe some measures were put in place to reduce the amount of trash produced every day?

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    $\begingroup$ It is very expensive to transport material to the ISS. So the funds for transport limit the amount of trash. $\endgroup$
    – Uwe
    May 15, 2019 at 8:31

1 Answer 1


The obvious natural limit on amount of trash comes from the law of preservation of mass: they can't make more trash than the amount of material that was delivered by a delivery spacecraft with a resupply mission. They pack all the trash into bags kept for that specific purpose, and when a cargo spacecraft is to undock to be deorbited and burn up in the atmosphere or land, it's loaded with all the accumulated trash, which then subsequently burns up in the atmosphere with the spacecraft or splashes down on Earth. (and obviously since it all fit on the way up, it fits on the way down.)

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    $\begingroup$ Have there ever been any incidents where something (especially anything valuable) was unintentionally put into the spacecraft-turned-incinerator by mistake? $\endgroup$
    – Dai
    May 15, 2019 at 19:36
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    $\begingroup$ @Dai that could make a nice question in itself. $\endgroup$
    – Pavel
    May 15, 2019 at 19:42
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    $\begingroup$ @Dai interesting question - you should ask it as a new question. I'd be interested to hear the answer $\endgroup$
    – Kryten
    May 15, 2019 at 19:42
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    $\begingroup$ Just because it fit on the way up doesn't mean it will fit on the way down, because trash may not pack as densely as the incoming cargo was packed. Unless they have a compactor up there? $\endgroup$ May 15, 2019 at 19:56
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    $\begingroup$ This might be worthy of another question, but ... is human solid waste treated the same as trash in this regard? Stored in containers and then placed in earthward bound vehicles? $\endgroup$
    – Moo
    May 15, 2019 at 22:27

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