Building a tier 2 ship hangar is one of the first few objectives you’ll receive in Halcyon 6: Starbase Commander. After getting a few ship fights under your belt, the game will prompt you to expand your fleet and build better facilities. This process is a little tricky, as you can’t simply upgrade your original ship hangar by heading straight there.
Instead, go back to your starbase, and look for the Tech Research room. This room will give you a large tech tree to look at, indicating all the facilities that you can build for your starbase. Look for the tier 2 ship hangar in the upper right corner, click on it, and choose to learn how to build it. Do note that you’ll need quite a large amount of materials and dark matter in order to research it properly. Once you’ve done this, you’ll then need to explore one of the ruined rooms in your starbase to clear it out. After that, you’ll finally be able to construct a tier 2 ship hangar there.
And that’s it. Once the ship hangar has been constructed, you’ll now have access to better ship blueprints, and you can scrap your older ships, and give your high level officers newer ones.