While under the command of Captain Darson, the Adelphi was assigned to a First Contact mission to the planet Ghorusda. The mission was centered around civilian specialist Tam Elbrun, an unusually talented Betazoid telepath, who joined the mission to facilitate contact with the culturally complex Ghorusdans. The situation was considered extremely delicate and volatile, and due to a misunderstanding, a conflict broke out.
In the incident, later known as the Ghorusda Disaster, forty-seven Adelphi crewmembers were killed, including Captain Darson, and two friends of Riker from his class at Starfleet Academy. Later, a Starfleet Board of inquiry blamed Darson for "carelessness" concerning Ghorusdan cultural taboos. (TNG: "Tin Man")
The Adelphi was named after Adelphi, Maryland, the home of one of the teleplay authors.