The Pi was a Romulan scout ship that was in service with the Romulan military in the mid-24th century. In 2366, the Pi was carrying out a covert mission when it crash landed on the planet Galorndon Core, inside Federation space. The Pi was destroyed with an ultritium explosive after the crash to prevent its capture by Starfleet. The USS Enterprise-D followed their distress signal and found the wreckage, determining it not to be salvageable. Two Romulan crew members were eventually retrieved. (TNG: "The Enemy" )