Automated repair unit
Automated repair unit is a ship special in Master of Orion.
ARUs periodically deploy drones to work on a ship's hull, allowing it to perform minor repairs during combat. Any ship equipped with an Automated Repair Unit is completely repaired after each battle.
Even though it's not stated in the English description, the drones can repair any ally ship, not only the one that carries this module. However, there is a trick. The repair system only activates automatically if the owner's ship took a hull damage. If the hull integrity is 100%, the system stays idle even if there are other ships nearby needing repair. To workaround it, activate the system manually, in which case it will proceed to repair the nearest ship that has its hull damaged (the owner's ship always takes priority).