So two suggestions for the Space Elevator:
1. Allow resources to be delivered to the Space elevator for milestone unlocks instead of manual insertion into the hub.
2. Split the Space Elevator tiers up. Currently, the Tiers come in pairs (1 and 2, 3 and 4, 5 and 6). I suggest breaking them up slightly and maybe tweaking them a bit so that each one builds on the previous set more and you get more interaction with the elevator. Odd number Tiers would contain schematics for new materials and researched alt-schematics. Even number Tiers would contain manufacturing, logistics or power upgrades to help automate the construction of the new Materials. Odd number tiers could have a higher unlock cost than even tiers to encourage automation of the previous set of recipes.