An early Earth spaceship lost at the galactic barrier about two centuries before the Enterprise found its recorder in 2265.
The SS Valiant was an Earth spaceship of the 21st century that disappeared about two hundred years before Kirk's time. In Where No Man Has Gone Before, the Enterprise recovered its damaged recorder marker near the edge of the galaxy.
The recorder showed that the Valiant had been swept toward the galactic barrier, that its crew had afterward searched desperately for information about extrasensory perception, and that the captain had then ordered the ship destroyed. Kirk soon understood why when the barrier gave Gary Mitchell godlike psychic powers.