What is "Object Space Lighting"?
According to the Star Swarm developers this helps them with LOD and enables greater shading scaling. Based on this I guess its simply texture space lighting.


  Because we do what we’re calling object space lighting, we calculate the projected size of each of those objects on screen, and based on that we shade it in a priority manner based on how large they are. We can scale the shading quality at a different frequency than we scale the geometry level or something else.


 A deep dive into the making of the eye-popping Star Swarm demo (interview)