Space Warfare adds the ability for space platforms to engage one another in combat, and a few other things:
- New space locations to fight over
- Ground-based enemy detection radars
- Blockades
- The Ship-killer kinetic impactor (S.K.I.)
- Unique items for each planet other than Nauvis, to balance out the PVP experience
- More to come!

Space Warfare adds very little to the singleplayer experience and is intended for use in a PVP setting where each team starts on a different planet.
For a mod that provides this functionality, see the mod Planet PVP by SpRiTz708.