eBay seller "partsandtrains" currently has parts of the Oak Point Nuclear Facility. Since direct links to eBay are not allowed and will go stale after a few months when someone searching the archives stumbles across this thread, some photos of the guts before they vanish:
There appear to be 2 circuit boards. If/when someone attempts a DIY repair, I'd like to see some photos of these boards from a better angle to see what's on them.
The motor looks like an off-the-shelf DC motor with a gear-train assembly in the round plastic housing. In looking at online videos of the spinning "disco" dome, I'd say the output speed is around 10 RPM. Again, if/when someone has it taken apart, perhaps there are some markings on the gearmotor assembly...or at least provide dimensions to help track down a replacement/alternative if indeed the motor failed. I can't imagine Menards would have designed/specified a CUSTOM gearmotor and with some luck perhaps an off-the-shelf replacement could be found. Not saying this is it but many choices out there that don't break the bank:
Or, if the motor runs but the disco dome does not spin, perhaps it is as simple as tightening a loose screw as @lstoll suggests.
Note to self: Since Menards buildings are powered by 4.5V DC, and many generic gearmotors are nominally driven at 12V DC, it may be that one of the circuit boards (e.g., the one with the large square inductor) steps up 4.5V DC to 12V DC.