What would happen to the ISS if we stopped maintaining it?

Question

What would happen if the astronauts on the ISS stopped maintaining it, and no further vehicles or remote control commands were sent up from the ground? I'd like to know what systems would stop working, what would burn out, fail, jam, freeze, overflow, etc, at what point the astronauts would die, and in what order the station would break down into a heap of unrecoverable junk.

To prolong this experiment, let's assume it was in a much higher orbit so orbital decay wouldn't become terminal for hundreds of years. I am just interested in the process of decay, and if/when a steady state eventually gets reached, what would be salvageable and what would be ruined.

If you can, please format an answer as a rough timeline or chain of events, with guesses as to the durations, and comments on interesting events where appropriate. Answer should include much info on the main life support failures, but also cover the other subsystems, and can span hundreds of years if necessary. Please include: power generation, truss bearings, cooling, stations attitude, pressure, water and o2 content, long term viability of electrical systems should power ever be restored.. What is no longer salvageable and repairable after 10years, 20, 50..

Answer 1

It would slowly come down into the atmosphere and burn up. There is also the possibility that pieces of it will reach the surface of the earth. But probably before that, the ISS will be hit by space debris, as no one will control it to maneuver the ISS away from the junk. Once the amount of junk is big enough, it will keep smashing into each other and create a whole lot of space junk. This is why it will be de-orbited to point Nemo in the pacific, the place that is the furthest from any inhabited land, after the final mission. Water and oxygen probably will not run out since it's not used as extensively. For the power: as long as the systems aren't damaged, it will be available. The main solar panel gimbal system is fully automatic. I think it'll be over for the ISS once completely left alone in about 15 years. But the space debris issue is the most important one, the ISS doesn't automatically move out of the way, but once upcoming debris is detected it can be moved from Earth, to avoid collision. I can't seem to find anything about how often this happens, though.