Whenever such an announcement is made, I keep asking myself something along the lines: "Just how much stuff did they put on board that thing, that there is always some way of using something differently or something different, to get back a working connection???" Incredible engineering.
Working in the government space sector, generally speaking, you're given a mission lifetime which is seen as a minimum. your payload/spacecraft/instrument needs to last at least this long. some things end up being limited by the physics of the system (See the RTG on the Voyager probes for a common example, or CEMs on plasma spectroscopy instruments for a more obscure example). However, in pretty much all cases where the physics doesn't put a hard cap on the thing you're building, nobody wants the thing building to be the first thing, or critical point of failure of the whole system.
jval43's quote puts it pretty well. It's not just that you're designing something to last, you're designing it not to fail. It also tends to help when you have a bunch of really smart folks from a number of disciplines working on the same problem.
With that said, you need to walk a fine line as far as the level of redundancy and fallbacks you put in place versus the overall SWaP (Space Weight and Power) of the system. I can go somewhat deeper into SWaP issues if you would like.
I remember learning about Hubble telescope losing its gyroscopes in one axis so it couldn’t balance and was effectively dead until someone clever figured out you could use the pressure from the sun to act as a third axis of motion to keep the craft stable. Sometimes it’s not just the stuff onboard but the ingenuity of the engineers that saves the day
