One of the specialized auxiliary spacecraft carried by a starship is the captain's yacht, a multipurpose vehicle normally used for diplomatic missions.
It is located (when docked) at the very bottom of the ship's primary (saucer) hull.
The yacht's flattened elliptical design allows it to travel both in space (approaching speeds of 0.65 times the speed of light) and in a planetary atmosphere (at a cruising velocity of Mach 6).
It's small size belies it's ample interior accommodations, consisting of the flight deck, two staterooms, crew bunks, galley, and an engineering section, along with the ship's impulse engine, cryogenic reactants and atmospheric flight motors.
The yacht is normally piloted by a crew of two, with other crew or support staff as missions dictate.