The USS Danube (NX-72003) was a Danube-class runabout and the first ship of its class. Ship Recognition Manual, Volume 1: The Ships of Starfleet gives the Danube's registry as NCC-72003. In 2365, Starfleet started construction on the Danube at Utopia Planitia Fleet Yards. Three years later, test flights were undertaken from Mars's surface, and warp drive tests were underway in the Sol system while the Danube's initial sister ships were undergoing construction. (Star Trek: Deep Space Nine Technical Manual)