Linking problems to external factors is best, IMO.
Random failure is a result of shoddy engineering, but meteorites popping your bubble every now and then is a natural hazard.
Similarly, solar panels could stay clean by default, but get dirty faster than now when the dust storms are blowing.
Falling rocks should be visible when missing your modules too, and perhaps you can dig them up for a little ore after the fact, so they're not merely problems, but opportunities :D
Edit:
Oh, and dust storms could blow seeds in from off-map to spawn new native plants. (with much slower growth than your greenhouses?)