Name of Skybox in rd_asteroid

Hello, I'm making a space themed Attack/Defend Map, I'm trying to look for the skybox from rd_asteroid but I can't find it. Does someone know the name?

 

I believe the sky in that map is a 3d skybox with: pitch black walls, an info_particle_system for the stars, and a sprite/brush/something similar for the Earth.

 

partly right, it's a big black room with a partly dome-shaped model called moon_nebula01 with stars being a model called moon_stars01. The sun in the distance is a texture called space_horizonglow01

 

Thank you, this is what I needed to know.