The original Excelsior class was a physical filming model designed by Bill George and built at Industrial Light and Magic for Star Trek III: The Search for Spock. The model also appeared in the next film The Voyage Home and was relabeled for use in the first two seasons of The Next Generation. The model was refurbished for its appearance in Star Trek VI: The Undiscovered Country. The model was again refurbished with entirely new arrangements and details to represent a refit modification, the Enterprise-B in Generations.
The refit modifications were designed by John Eaves under the supervision of production designer Herman Zimmerman. Since the original model was no longer in its original configuration, a new one was built by Greg Jein when the Excelsior appeared in the Voyager episode “Flashback,” if at a smaller scale. This model continued to be reused until a CGI Excelsior was built for later seasons of Deep Space Nine and Voyager. Despite its age, the Excelsior has become one of Starfleet’s most frequently seen “guest star” vessels.
Although the Enterprise-B had already been established as an Excelsior class starship, the producers of Star Trek: Generations felt the Excelsior had been seen too many times in previous films. They wanted a brand new design.
This presented a challenge to the movie’s art staff. How to maintain continuity while giving the audience a “new” ship? John Eaves explained in Star Trek: The Next Generation Sketchbook, The Movies (1998), “The Excelsior has always been my favorite of all the starships. Bill George’s design conveyed power, elegance and beauty, so when the task fell to me to modify the ship, I was both thrilled and concerned.
Fortunately, Mike Okuda came over to the feature art department to discuss changes that would significantly alter the ship’s appearance while keeping her original lines. […] his focus and direction for the modifications were extremely helpful. So together, we set to work on the details.
First, I took an ILM photo that showed the Excelsior in Spacedock, did a rendering, and started putting add-ons on the ship. […] Mike [Okuda] pointed out that we needed to design an area that protruded from the ship, so that the energy ribbon could whip out a section while leaving most of the ship intact. So we built a section of decks extended out from the main body, which tapers gently on the bottom and flares out dramatically on the top. We also did a detail sketch of the area round the deflector disk, designating one area as the reactor room.
The added girth increased the overall size of the vessel, while still retaining the original Excelsior design. We made a few other design changes, such as taking two fins off the top of the saucer, and putting in two major impulse engines, one on either side of the existing impulse engines (we figured these stronger engines would be needed when the saucer detached). As for the nacelles, we added a cap to them, plus a dorsal fin on top and a running fin on the outer edge.