Not much deterioration can occur in a vacume. Take the Titanic for example, soaking in deep water for over 70 years, but much of the metal is intact due to the lack of oxygen at that depth. Had that ship been in shallower water where there is more oxygen in the water, it would have been in far worse condition. But oxygen isnt the only element that causes decay, other elements can also cause the decay process to move faster than normal.
In space, radiation can increase the decay process. The situation with Mir is an example, just like SkyLab. In fact, any device up there now is subject to the elements of space, be it micro-sized asteroids beating against the hull, radiation penetrating the metal that makes up the hull, heating it like metal can heat up in a microwave oven. Constant expansion/compression of that metal as it circles the Earth, especially geo-syncronus orbit birds, they are exposed to the sun, then darkness as they follow the Earth rotation. A majority of the birds are below the Van Allen radiation belt, which starts at about 10 thousdand miles above the Earth and strech to over 100 thousand miles up.
Its the Earths natural electromagnetic radiation belt. A very powerfull shield protecting us from the sun's deadly gamma and x rays. This radiation can deteriorate a ships hull if it isnt built using materials that can withstand that radiaton, and the hull must be able to absorb or deflect that radiation, otherwise, the occupants inside the craft will cook like an egg placed into a microwave oven, or suffer severe radiation poisoning. What is interesting, is that if the space suits used for the moon trips are able to withstand that much radiation, why cant they be used to clean up some of the nuclear reactors that failed, like Chernobyl or Three Mile Island?. The space suits are supposed to be able to withstand all that radiation in space, which is hundreds of times more powerufll than any nuclear radiation leakage we can come up with. Makes ya go, "Hmmmm"...(Arsenio Hall?)
RFB