As reported in LinuxDevices.com,

Linux was shot into space Dec. 16, as part of a second-phase Air Force Research Laboratory program aimed at making space more "operationally responsive." The TacSat-2 (tactical satellite) program aims to create "micro satellites" that can be launched quickly and cheaply, to support tactical military operations.

Now how many times have to heard of Microsoft Windows being used in mission critical applications that are out of this world, literally?! :) This goes to show that Linux is trusted by the US military with this launch being the second in a series, which the first one reported in 2005.

I wonder if Windows were launched in a satellite and it BSODs? Hmmm.