The satellites themselves are most likely running some sort of proprietary or semi-proprietary RTOS for their C&DH computer (eg: VxWorks, QNX, Integrity, RTEMS...).
However, it's more than likely that there's a bunch of Windows machines on the ground segment side of the operation, since a lot of satellite fleet management software is Windows based.
However, it's more than likely that there's a bunch of Windows machines on the ground segment side of the operation, since a lot of satellite fleet management software is Windows based.