I'll admit that I'm walking a dangerous line with the "no true Scotsman" fallacy. I stand by my judgment of the examples cited, but agree there is some room for debate.
I think the NASA example fails not because I'm being too narrow, but because the initial stated objectives were so fuzzy and broad. More importantly, these stated objectives were probably just secondary, a rationalization to enable the true objective - the nationalistic desire to win the "space race" against the Soviets. JFK, who initially got the whole ball rolling, actually wanted nothing to do with space exploration. His backing of it was really just a political ploy. (of course, in pointing this out, I'm making your point to a certain degree: JFK set out to score political points, and in the end he wound up bringing us velcro and ICBMs - yes, I'm being snarky there)
That said, you've also given me the best reply to my question: ARPAnet. While it wasn't large at the time, it was certainly complex (beyond my ability to understand all of its technology, anyway). And since it was developed for defense purposes, the end positive consequences are in a whole different ballpark than what was originally planned.
Anyway, what really drives my questioning here is a Megan McArdle post from yesterday [1] about a political science class at John Hopkins about policy failures. She quotes the prof. as talking about opening minds to critical thinking about the endless ways in which the best-laid plans can go awry.
[1] http://www.bloomberg.com/news/2014-02-04/learning-from-iraq-...