Oh my, a lot of really interesting ideas in this. First of all - kudos for producing 20 minutes worth of audio, that alone is commendable. Furthermore, the production and mixing is really well done, and great job executing on the theme with the music and the write-up.
This made for a fun listen as a whole. I love how you've delved into the typical go-to's for sci-fi scoring but you put your own spin on the process. Big fan of the various pulsing bass and synth lines - I always think these are a fantastic way to add a heartbeat to a piece without using progression. There's also plenty of really neat sound-design present throughout; from the metallic, bell-like melodies to the airy pads and textural drones that come in and out.
The acid-esque bass that comes in around the 9 minute mark is awesome - big fan of this sound and the patch sounds great. Percussion is used to varying extents throughout - I like how sometimes we have actual drum rhythms to ground the arrangements and other times there's more liberal use of esoteric rhythmical patches or minimal percussion (or even none) to lessen the emphasis of being on the grid.
Major kudos on the textures and drones, particularly those toward the end. Does a great job of really setting up the great expanse of space. It can be hard to really nail the tone with these and keep the sounds congruent but I think all in all this is a good example of it being done well.
Great work, this was a delight to listen to, and it has a lot of neat little details the more you focus in on. Best of luck!