From my perspective, the number one reason we had a well functioning satellite out of the gate is my philosophy of testing "safe mode first". What that means is in a graduated fashion, test that the hardware and software together can always get you into a safe mode - which is usually power positive, attitude stable, and communicative. So our software integration flows hit this mission thread over and over and over with each update. If we shipped a new software feature, make sure you got to safe mode. If we found a bug that prevented it, it's the first thing to triage. We build out our pipelines to simulate this as much as we could and then ran it again on the development hardware and eventually would load a release onto flight once we were confident this was always solid. If you're going to develop for space, start here.