Another factor is that when NASA says the expected mission life is like 30 days or whatever, it doesn't mean they are designing to just meet that 30 day target.

Another factor is that when NASA says the expected mission life is like 30 days or whatever, it doesn't mean they are designing to just meet that 30 day target. I can only speak to mechanical design, but the margins that NASA uses are huge, at least compared to consumer tech (I've worked in both). The 30 days is more like what they are "liable" for achieving per their directive. Liability isn't quite the right word, but the missions are pretty small in their official spec/definitions.