HI I have extra planets installed and I dunno why it crashes. I have follow a guide on enabling compatibility between the different space mods but still causes some issues.
It appears that overworld mobs are trying to spawn on the moon or they can't render when your using the galaxy map & this crash glitch happens in 1.7.10 as well its the galacticraft mod erroring on render screen of the galaxy map. you may have to use a different version or build of galacticraft. Also the Forge.cfg allows you to turn remove erroring entities on but automatically disabled on default.