I am often inspired by the Voyager program because I see it as one where the program planners did not put limits on themselves. And the fact that it would be 40,000 years before the problem came close to another star was also fascinating.

And then I consider that its only been in the last decade were we've been looking at asteroids in an effort to identify potential disasters before they happen. If some alien probe went through our solar system, it is only just now that we would notice it at the size of Voyager, and then we wouldn't pay attention because if it re-entered the atmosphere it wouldn't do significant damage. Doesn't bode well for the aliens seeing it unless they are looking for it.