A tractor beam emitter was a starship component that projects a graviton beam called a "tractor beam". This graviton beam was capable of either attraction or repulsion. The shuttlebays aboard Federation starships each have a tractor beam emitter mounted near the shuttlebay in order to guide shuttlecraft in. In addition, each shuttlebay has a tractor beam emitter mounted within. (TNG: "Time Squared" ) In 2377, the USS Voyager's Emergency Command Hologram escaped from Quarren ships by firing on their tractor beam emitters. (VOY: "Workforce")