"We had hundreds of thousands of people all dedicated to doing the perfect job, and I think they did about as well as anyone could ever have expected" -- Neil Armstrong
Greg Kroah-Hartman spends almost all (99.7%) of his F/OSS activity on Linux-Kernel based on the mailing list archives.
Source: http://www.mentby.com/greg-kroah-hartman/
Will there be any mission that needs to be done on board a supersonic stealth aircraft, or a spacecraft? How about a mission involving an "Alien" computing system (i'm not referring to a Dell/Alienware).