Mars Phoenix Lander - A Victory for Open Source
Space agencies were some of the first places you could find open source software "in the wild". Being natural early adopters, cash-strapped and very inquisitive they naturally took to the concept.
Additionally they were some of the first users of ARPAnet and subsequently the Internet which gave birth to this movement. Today this marriage between rocket science and open source saw its latest victory with the landing of NASA's Phoenix Mars Lander.