[sliken]

Seems a bit silly, you can buy a glass sphere with small closed ecosystem that can last years with indirect sunlight. Surely we can manage something that recycles astronaut poop/pee into something vaguely edible with the help of bacteria, fungus, plants, and algae. Sure some genetic editing (of humans, bacteria, fungus, plants, and algae) might be necessary. Even just some minor tweak like happened in the last 1000s of years to make humans more compatible with cows milk.

[tsimionescu]

That is taking energy from the sun, and it is relying on the Earth to maintain certain temperature parameters. It won't last 10k years anyway. If nothing else, the glass will probably degrade over a long enough period of time. There's also a constant chance of a freak mutation destroying the equilibrium of the system.

In outer space, cosmic rays will make this process faster. Also, in outer space, it will need a constant source of light for biological reactions, and also just to keep from slowly cooling down to 0k through heat emission.