No matter how good you are at Homeworld 3, your units will take damage during battle. Instead of just throwing them away, you can heal them.

During battles in Homeworld 3, you’ll spend a lot of time building and researching new units, from Interceptors to Fleet Bombers. While these may not cost you a lot of resources, you’ll still want to have as many units as possible so that you can join the fight when you need them. Ideally, you’ll want to repair all of your units between encounters. This may not always be possible due to cinematics and mission transitions, but you should always aim to have them repaired.

Here's how to heal units in Homeworld 3.

There is only one way to heal units in Homeworld 3, and that is to attach them to your mothership.