Okay going to say this, that this starts out OK, but to me it easily feels like micromanagement quickly rather than an idle game. So here are (my) suggestions one could implement to make the gameplay smoother.
Implement an auto-sell feature for different aspects (primarily low level asteroids E & D rank at minimum sometimes C)
Implement an auto sell feature for elements. For example Copper (Cu) and Hydrogen (H) at current aren't needed for any of the formulas so they could be auto sold. After getting all 3 girls up a rank this similarly applies to each prior set of elements. (Iron & Helium for D, Silver & Oxygen for C etc)
Either significantly reduce XP requirements for skill ranks with B rank upwards, or MASSIVELY increase the XP yields on every skill. At current the only one of the skills imo that is close to where it 'should' be based on the current XP yield is refining and even that is a bit slow imo. (I have every facility at S rank since it says facility lv influences XP yield)
Implement a feature that auto navigates to the nearest asteroid in your list once the current one is done mining.
Likewise give us something that automates once you arrive at an asteroid, the neko currently navigating automatically goes to mining, mines the asteroid, and then goes back to navigation. I swear this is like over half my overall time at this point.
An upgrade that in refining once a smelter is empty it will automatically go ahead and then start refining it into its next tier instead of sitting idle. (if you can make it so that it is programmable to a 'max' refinement even better!)