Mirok's science ship was a Romulan science ship that was in operation with the Romulan Star Empire during the 2360s.
In 2368, this science ship was the test bed for a prototype interphase cloaking device. During the test, it experienced a forced chamber explosion in the resonator coil. Following the explosion, one member of its crew, Parem, was phased out of reality by the device, and all but at least seventy-three of the crew died. Among the dead was the ship's captain, leaving science officer Mirok in charge.
The ship was assisted and repaired by the USS Enterprise-D, which offered the science ship a modified Federation subspace resonator to act as a new graviton generator, which limited the ship to warp two during its return to Romulan space. They also received a Federation computer core from the 2220s or 2230s, presumably to replace their own. (TNG: "The Next Phase")