Didn't the Terminators get somewhat *creaky* when their outer shells were damaged? It's been awhile since I've seen any of those movies. Would the rovers make more of a humming sound, then? Does it whirr? Any clicks or beeps? Does the Martian regolith quietly go "crunch"? I realize there wouldn't be any reason to deliberately make it quiet, but generally speaking, electronics are supposed to work quietly when they're functioning right. I'm just wondering if there would be any other noises associated with it traveling or doing anything else it's supposed to do. Thing is, I've watched coverage of probes landing, taking pictures from space - but naturally we can't hear what it sounds like. I'm not imagining R2D2, but I am wondering if it makes sounds similar to a normal computer, and how loud it is when it moves.