What is the difference then? When you use Go to do real time measurement with strong real time requriements, then how does Go not fit real time system?

Are physical measurements in real time not a real time system? How are these things classified?

At least I have heard that Go is popular in realtime setting at NASA in ways which Java, C# etc are not.

Task switch blocked due to GC you say? This isn't my field, so I don't know what the requirement of these task switches are but Go GC has a pretty constant GC delay of 0.5ms Java get get up to 100ms so tha tis a big difference.

Secondly you can control much better how much garbage you produce in Go.