A 32nd-century starship design feature in which the warp nacelles are held in position without any physical pylons, introduced to the USS Discovery during its refit at Federation Headquarters in 3189.
By the 32nd century many Starfleet vessels no longer join their nacelles to the hull. The nacelles float beside the ship, held in place by fields, and can shift position, which is said to improve both manoeuvrability and the efficiency of the warp field.
The design is first seen in the Discovery episode Die Trying, when the crew arrive at Federation Headquarters and marvel at the fleet gathered there. In Scavengers their own ship receives the same upgrade, along with programmable matter interfaces, and is redesignated NCC-1031-A.
The refitted ship keeps this configuration for the remainder of the series, and the same approach is visible on most of the 32nd-century Starfleet vessels seen in Discovery's third, fourth and fifth seasons.