galactic-civilizations-3 – How to Disable Galactic Civilization 3 Debug Log

According to a response to the post "quickest way to regenerate ship health?" in the Gal Civ 3 steam forum:

Sitting/moving in space repairs 0.75 to 1.25 points per turn (every third turn you get zero, one or two points depending on your repair rate). Orbiting a planet repairs at 4 x this rate (three to five points per turn). Shipyards and star bases are almost as fast as planets for repair.

Faster repair times are available via research; however, they become available in the mid to late game period.

This is the closest I've found yet about the official repair rules.

The Altarian and Drengin have the Unwaivering trait, meaning their planets are immune to being culture flipped. You could play as either race (or a custom race with the same trait).

Other than that, culture flipping seems to be the way to specifically prevent this type of behavior. In Civilations, players are limited to building cities 4 tiles removed from another. In GalCiv, you can populate any planet regardless of its surroundings, but cultural influence prevents you from doing so in most cases.