Citing stability issues NASA has announced they will be migrating the ISS laptops and PCs from Windows to Linux. Being a long time Linux user and typing this on a Linux system I am happy to hear about this change. Linux has been used in many of the ISS systems but it nice to see the move to the workstations as well.
It looks like NASA is heavy into Debian but also uses Red Hat and Centos. The ISS workstations will be Debian 6.A quick search for Linux on the NASA website shows that there is a substantial Linux culture at NASA within research and operations. Lets not forget the recent Robonaut 2 Linux powered robot.
They have contracted with the Linux Foundation to get the astronauts and specialist up to speed with the OS change. Information on this can be found here: Linux Foundation
UPDATE: More now being reported at ZDNet