Knowledge of this starship class was contained in the Vulcan database, but the class remained unknown to Starfleet until May of 2154, when two Orion interceptors attacked and raided the Enterprise NX-01. The two interceptors quickly caught and ambushed Enterprise in the Borderland as it was searching for an Augment-controlled Bird-of-Prey. Using their transporter, the Orions were able to abduct nine crewmen from Enterprise, including T'Pol and Jeffrey Pierce, before their escape.
Later, two interceptors again engaged Enterprise, following its rescue of the abducted crewmembers from Verex III. They caused moderate damage to Enterprise before the Augments arrived in their commandeered Bird-of-Prey and forced both of the interceptors to retreat. (ENT: "Borderland")