From the Readme.md in the oolite-mesh-converter repository on github:
Bug reports: currently, Obj2DatTexNorm.py is the only one that can be considered actively maintained, and the others have known problems.
I think that is the main problem you are facing. However, and in case you would be interested in doing some testing (since no-one else apparently can), you can try doing the conversion with the updated Dat2Obj programs contained in Pull Request #1 from that repo (note: not official code yet). Diff to the versions currently in master is: https://patch-diff.githubusercontent.co ... ull/1.diff
- Above mesh is cobra1_redux, it looks very simple, I believe it is one of older models? If yes, why is it still in game files?
Yes, it is the old version of the model and all old model versions are included in the game files for reasons of compatibility with older OXPs which are like_shipping their ships with those old variants.
- oolite_cobra3.dat looks like much more advanced model based on reading .dat file in text editor. Any idea why Dat2Obj converts it to .obj with zero verticies? Mesh is empty.
- I've checked github https://github.com/OoliteProject/oolite
... ter/Models How to open these .mesh files?
The .obj files for the new models are inlcuded inside the ModelsPost-1.80.obj folder in that repository. Why not trying to load those directly on to Blender?