Nacelle
A nacelle is a large outboard structure that houses a warp-drive engine. The interior of the nacelle is dominated by two rows of massive semi-circular warp-field coils that serve to transform the ship's drive plasma stream into the subspace field that makes faster-than-light speeds possible. The warp coils create a subspace displacement field, which "warps" the space around the vessel allowing it to "ride" on a spatial distortion, and travel faster than the speed of light.
Nacelles are typically separated from the ship by large pylons, and usually house a Bussard collector at the front end. However, some starship configurations have nacelles that are integrated into the ship’s main structure without pylons.
A nacelle's interior also includes a small control room, accessible in nominal conditions by a Jefferies tube that permits maintenance and monitoring of the system's operation.
Star Fleet vessels have a varying number of nacelles. Vessels with more than one nacelle can still operate with damaged nacelles, however it will be at reduced warp speeds. The damaged nacelle(s) must be taken offline.
