Aboard the Galaxy-class USS Enterprise-D, the nacelle tube included a small control room, which was found on deck 25, at the rear of the nacelle, near the plasma injectors. The control room was accessible in nominal conditions by Jefferies tube only and was comprised of two levels, with isolation doors providing access to the interior of the nacelle itself. The isolation doors could be opened with the protection of a one-way force field. The doors, however, could only remain open for ninety seconds to prevent force field degradation and the release of drive plasma.
In 2370, the starboard nacelle tube control room was manned by Lieutenant Nara and Lieutenant jg Daniel Kwan. On stardate 47622.1, Kwan committed suicide by jumping through the force field and into the plasma stream, echoing a similar event that occurred during the construction of the ship in 2363, when Lieutenant jg Walter Pierce committed suicide in a similar manner. (TNG: "Eye of the Beholder").