Atmosphere physics.
Time: date, time scale, day length, pause.
Sparse Gaussian clouds.
Lights, environment, fog and exposure.
Moon disc and moonlit sky.
City lights on the night side, seen from altitude.
Where the observer is and how render space maps onto the planet.
Seeds the stars, meteors and procedural planets (unless they set their own seed).
Labelled altitude shells (troposphere, ionosphere, Kármán line, apogee). Off by default.
Meteors.
Star field and Milky Way.
Sun disc.
The star system (star, home planet, moon, procedural planets).
Every
Skysetting. Plain JSON: save it, send it to a worker, bind it to a GUI.