Utility modules are split into 3 types: Engine, Power, and Support.
Some modules have alternative versions like Mk2 and Mk3 that are either purchasable in Black Market, or unlocked after beating a sector.
Engine, in Utility category, a module type for moving a ship to add mobility.
Power, in Utility category, or to be called reactor, power modules supply power to other modules. Ships with power deficit will periodically shut down. Power modules explode upon destruction, potentially damaging other nearby modules.
Support, in utility category, only Repair Bay in this group.