Star Control 2 style planet landing - texture generation

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:bust_in_silhouette: Asked By davidpwbrown

Hello there - very new to gamedev
In my project I am aiming to have a lander land on a planet and scoot around and pick up resources on a 2d background like in the old game Star Control 2 ( ur-quan masters modern open-source remake)
i got quite far with this, using external programs to generate random planet backgrounds.
The snag is that for the variety of planets and the size of the background images, my project would be over 10GB - very unwieldy for such a simple game
I checked how the open source version of Star Control 2 did it, and I saw they generated the textures in-game.
i was trying to achieve a similar effect with the softnoise plugin
And attached that algorithm to various outcomes such as a tilemap - which when scaled up to huge backgrounds had very poor performance , I realised that tilemaps werent really required, just a static background.
So then I looked into texture generation or pixel manipulation directly of an image, and couldnt quite understand the concepts or how to make it work.
Could anyone point me in the general direction of how to use the noise algorithm to directly manipulate a texture( colour gradients etc ) that could then be applied to a background sprite?
I understand quite thoroughly about general node construction and gdscript, but the manipulation/creation/swapping around of resources such as textures, baffles me.