(covers information from several alternate timelines)
Maiden voyage was a term used to describe a ship's first expedition.
In 2256, the crew of the USS Discovery, stranded in the mirror universe, discovered that their captain, Gabriel Lorca, had been an inhabitant of that parallel universe all along, posing as his prime universe counterpart. Afterwards, Acting Captain Saru stated that the vessel was no longer Lorca's, but the crew's, and that they were undertaking her maiden voyage. (DIS: "What's Past Is Prologue")