This is the premise: the occupants of a spaceship die hundreds of millions of years in the past orbiting above a Earth-sized planet. It has a supercomputer that allows the ship to still fire its rockets if it detects even slight orbital decay. The ship has enough power (i.e., a megaton neutron reactor, generating 7.50x10^13 joules of energy per kilogram) to sustain its orbit and to power its machines.
However, when the occupants died, the organisms that live on them didn't die. So, now when the bacteria-analogues evolved for hundreds of millions of years into metazoa and all the machinery has rusted except for the rockets, would the ship still stay intact?
I'm asking if the spaceship will stay intact under the radiation of the extreme proximity of a white subgiant star (maybe an F0IV or something like that), stellar wind, interplanetary particles, and cosmic radiation, if that clears it up. I gave the information about the metazoa for background.
The neutron generator works on beta radiation so electrons and protons come out of the rockets. Whatever energy is not used for powering the ship is not drawn from the electrons and so let them fly out of the rocket unhindered. It does not generate neutrons; it generates electricity from beta decay. Once a neutron decays, the electron is launched out of the neutron core. This would mean that when the core decays completely, the products would be a proton core, which would cause the ship to explode because there are too few neutrons. This won't happen anytime in the near future. I found the energy density of neutronium by the mass of a free neutron and the energy that the electron has once it undergoes beta decay.
The atmosphere would be nitrogen dioxide.
Instead of using beta decay, would it be better if I use metallic hydrogen and rely on that to recombine to provide electricity and use something like hydrogen peroxide as propellant?