“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.”
Official statement of the United Space Alliance, which manages the computer systems for the International Space Station (ISS), regarding Linux usage on the ISS[1][2]
The use of free software instead of proprietary software can give institutions better control over information technology. A growing number of public institutions have started a transition to free-software solutions. This grants independence and can also address the often-argued need for public access to publicly funded developments. This is the only way that public services can ensure that citizen data is handled in a trustworthy manner since non-free software doesn't allow total control (or even knowledge) over the employed functions of the needed programs.
See also : List of Linux adopters and List of BSD adopters