The astromech socket, also known as the astromech slot, astromech port, droid slot, or droid socket, was a component of some starships, usually snub-fighters, where an astromech droid could be attached externally to provide piloting assistance via a computer interface within the socket, and to provide maintenance to the vessel when required.
Astromech sockets were typically present near a ship's core mechanical compartment, namely the engines, of which could be in close proximity to the socket for maintenance accessibility.
In some cases, like the Phantom, an astromech was needed for a ship to enter hyperspace.