"We migrated key functions from Windows to Linux because we needed an operating system that was stable and reliable -- one that would give us in-house control. So if we needed to patch, adjust, or adapt, we could." -- United Space Alliance, which manages the computer systems for the International Space Station (ISS).
@nixCraft Many years ago, I had a Linux kernel credit for helping out with a device driver that was, to my surprise, later used for data collection on the Space Shuttle.