Quirrelmort knew of Voyager, knew where to find it, knew what building, what campus, how to defeat the many security systems, and so on. This bespeaks an intimate and long-standing interest in NASA's projects.
Well, all the bits after finding out about Voyager could be done with the liberal use of Imperius, legilimency and other magic.
Alright, I'll modify my intimately familiar claim. He needs to be only reasonably familiar. Up in the top few percentiles of Americans/Englishmen vis-a-vis space knowledge, but not much much higher.
However, if you assume he got in just by using Imperius, this reinforces my point about the respect Quirrelmort needs for Science. A normal arrogant wizard wouldn't even bother to ask his pet muggle NASA technician to disable all the alarm systems. ('Alarm systems? What are those? I don't detect any wards or magical traps, therefore I can just walk in and make a horcrux.')
ETA: There is now a third thread, so send new comments there.
Since the first thread has exceeded 500 comments, it seems time for a new one, with Eliezer's just-posted Chapter 33 & 34 to kick things off.
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