Played some more, here's some more feedback. I'll try to avoid talking about QoL or the interface as I understand it's a prototype, but will concentrate on the game's mechanics and dynamics.
- The distribution of resources on expansion asteroids doesn't guarantee continual expansion and research, e.g. my last run all close asteroids had only Rock and Gold.
- Consequently, it seems impossible to get very far in a single run, you need to get as much research done as you can before you run out of materials and exit to the main menu and start a new game. It was mentioned in DeCell's comment below already, I assume research carrying over is intended.
- The gravity system seems to mostly just slow the game down without offering much for gameplay. It encourages entirely mining out an asteroid before exporting anything from it, which has an anti-synergy with the tier 3 lab. A small nitpick is that harvesting resources shouldn't really be decreasing the asteroid's gravity anyway, as the matter is still present on it :)
- I found myself spamming the POW UP button a lot until I could get sufficient solar panels online, in my opinion a small passive power income from Hubs would be a nicer way to jump start your economy.
- (sorry, this is QoL) Still haven't come across any Tube filtering tech, if it is higher in the tech tree I would suggest it being lower. Currently fuelling and loading Landing Pads requires a lot of Depositing, and it's hard to control what cargo goes in unless you've set up a resource-exclusive warehouse - which is also difficult to do without filtering.
- One thing I'm really loving is dealing with the small amount of space and needing to constantly be shifting your production lines to meet the current requirements.