Detail this asset from Unity Store: Original Link
This is a paid asset, but now you can download SPACE for Unity – Space Scene Construction Kit Free.
SPACE for Unity – Space Scene Construction Kit v1.5
SPACE for Unity – Space Scene Construction Kit v1.06
June 2019: Version 1.6 released.
* Added support for Unity 2018.4 and 2019.1+
* Unity 5.5.0 or better required.
* Simplified space scene creation (automatic camera configuration)
* Bug fixes and improvements.
Create unique space scenes with a single mouse click. Save money, distribution size, and memory through a modular approach to replace skyboxes!
Check out the included Warp Speed effect: warp speed effect and fast space scene travel.
Watch HD Video Trailer (YouTube)
Hundreds of textures up to 4096×4096 (stars, nebulas, galaxies, planets, moons, rings, asteroids). Fully automated with optional custom filters to create specific moods. Camera effects and infinite asteroid fields. Fully documented and optimized C# scripts, detailed PDF documentation and video tutorials.
Planet Expansion Pack 01 with 28 planets
Tutorial videos: SPACE for Unity at imphenzia.com