Why didn't the vessel Red Dwarf degrade and decay during Lister's 3,000,000 years in stasis? Aside from some meteor strikes, the vessel seems to be intact. Only the bodies of the dead crew and the IQ of Holly appear to have been affected by the passing of time. I considered the service "scutters", but wouldn't time have ravaged them as well as their resources, therefore their ability to replace and repair 3 million years' worth of worn and damaged equipment?
Well, realistically speaking, the show shouldn't have happened at all, since the ship would have deteriorated to the point of losing functionality. Three million years is a really really long time. The scutters would have started to fail after a while, and even if they could repair each other as well as the ship, the ship and its systems would have run out of power, fuel, and spare parts long before 3,000,000 years had gone by. Not to mention that all the food we see the crew eating would have spoiled before even 1,000 years had passed, even under ideal circumstances (I doubt the ship had enormous stasis fields serving as larders, since it wasn't expecting such a long voyage).
But of course, we're not supposed to analyze this realistically. We're supposed to take it for granted that the ship and its contents remained in good condition after all that time (except Holly's mind of course), almost as if the whole ship went into stasis. I don't mind, personally; it's a fun premise even if it wouldn't work in reality, at least not as depicted. I'm happy to see them run with the idea and they did it well.
One small thing I think they could have done better, though, was: in the pilot, they could have been more creative with the piles of crew member remains, scattering them slightly. As it was, they were obviously just poured there--it would have been better if they had shaken them around a little so it actually looked a bit like a body had lain in place for that length of time.
It is safe to assume that a ship the size of the Red Dwarf had more than just a couple of scutters.
Most likely the ship started with a fairly large complement of scutters and possibly other service and repair units, and the ones we see may be the few remaining operational after 3 million years of automated repair units repairing each other as well as the ship.
Anyone ever consider the possibility that Holly LIED about how much time had passed? We know the computer has gone a bit 'wonky' over time; it is not unreasonable to suppose that it had to shut down for various reasons - extensive maintainance, self-protection from radiation and other space hazards, interference from the Cat-people - and in the process completely lost track of time (reliable clocks having ceased functioning in the interim). Holly has NO IDEA what year it actually is, any more than he has any idea of where they are in relation to Earth. His choice of 'three million years' is less a function of actual time passed, and more a function of keeping Lister sane (if everyone is 'long dead', then psychologically, the longer the better - 'three million' is too large to be entirely 'real' to Lister, so it is easier to handle).
Given how fast technology progresses, nothing I remember from the show suggests that more than about 5,000 to 10,000 years need actually have passed.
Just a thought.
Also wanted to point out that the explanation into the radiation leak is mentioned in Red Dwarf: Infinity Welcomes Careful Drivers as follows:
‘So, what happened?’ Holly told him about the cadmium II radiation leak; how the crew had been wiped out within seconds; how he’d headed the ship pell-mell out of the solar system, to avoid spreading nuclear contamination; and how he’d had to keep Lister in stasis until the radiation had reached a safe background level. ‘So … How long did you keep me in stasis?’ ‘Three million years,’ said Holly, as casually as he could.
The radiation that was blasting around Red Dwarf (providing of course it was a Cadmium-113 leak, has a half life of 7.7 x 10^15 years so maybe there is some scope for an answer to your question here.
Most decay comes from oxydisation (rust) assuming the Red Dwarf is built out of non-oxydising materials then the only sources of decay would be wear and damage. With no crew the ship would have been inactive, save for the hold where the cats lived. Scooping up the occasional asteroid would have provided plenty of material for the skutters to keep things going.