Is there any classification for a specific operating system used for a specific purpose ?
Yes, although SCADA has not quite arrived yet.
Do-178B is a standard used for qualification of system for aerospace. The FAA requires DO-178B compliance for software and systems on commercial aircraft. It is also typically applied to government and commercial satellites. There are operating systems which are DO-178B compliant: GreenHills Integrity-178B RTOS, Wind River VxWorks Cert Platform, HeartOS DO-178B, SYSGO PikeOS, DDC-I Deos, LynuxWorks LynxOS-178.
Theres is also the European Cooperation for Space Standardisation (ECSS). Although ECSS focus more on the process rather than the product.enter code here