Yup, that is correct, and intentional.
Due to the way AsteroidBelt is currently coded (as of v1.2.6), it is actually impossible to load the game with AsteroidBelt and Redrawn Space Connections, if Interstellar Travel is not also enabled.
Even though there is no inherent incompatibility, it is simply an error command thrown by AsteroidBelt when those two mods are detected without Interstellar Travel. There's nothing else preventing the game from loading except AsteroidBelt itself (as of v1.2.6)
The AsteroidBelt mod author needs to make an update (v1.2.7) in order to allow the game to load (presumably requiring this mod in addition to the other two). See discussion thread on their page for more information.
If you just want to "make it work", then I could upload a temporary modified version of AsteroidBelt v1.2.7 that simply removes those error message restrictions, and allows the game to load, it's what I've been using to test from my end. Attached via Google Drive
