Penal Colony 47

Penal Colony 47 was a Federation space station, a prison in Starfleet service in the 2400s decade. 

Specifications
PC47 consisted of six separate station elements. The primary station was identical in external configuration to Deep Space Station K-7. The primary station was surrounded by five other secondary stations composed of an asteroid base and a modular spar. Security beacons were modules on the ventral side. PC47 was defended by squadrons of light cruiser/frigates, runabouts, Federation fighters, and shuttlecraft. 

History
In the year 2409, a Klingon Defense Force team used a runabout stolen from Starbase 157 to infiltrate Penal Colony 47 and rescue KDF warriors captured in a Klingon raid on the Utopia Planitia Fleet Yards. The infiltration was successful, and the KDF forces escaped to a waiting battlecruiser.