Although usually used in a reconnaissance, courier or utility transport role, modules exist to convert the Danube Class Runabout to fill a light gunship, similar in concept to the PT boats of Earth's Second World War. The Photorp Launcher Module supplies a formidable boost to the runabout's offensive capabilities, with a "pop-down" photon torpedo launcher and a magazine of 20 Type II photon torpedoes. Three stack of three torps are loaded to either side of the launcher's centerline stowed position, with an additional two torps above the launch tube itself. The Photorp Launcher Module contains a pair of antimatter storage bunkers to arm the warheads of the torpedoes. A weapons targeting sensor is mounted beneath the launch mechanism to provide accurate target acquisition and lock. In peacetime, the Photorp Launcher Module may be used to launch standard full-sized probes, which are much more sensitive and flexible than the microprobes standard to the Danube.

The Photorp Launcher Module is an extended monoload payload module which requires the aft Crew Module to be removed. This means that on multi-day long missions, the crew must "hot-bunk" in cots in the Cockpit Module.

Dyson Base has one Photorp Launcher Module available. It is usually used to launch probes, as the Dyson Sphere Exploration Mission's objective is peaceful exploration of the Sphere. It is always a possibility, though, that it may have to be used to fire live weapons, and Dyson Base stocks 100 torpedoes against the eventuality that they will be needed.