Nova class model
Though having made only appearances in the  episodes, , as well as an otherwise undisclosed futuristic cameo version in s third season episode , , the design of this little  ship did became a favorite of Star Trek production staffers. 

As a class, the four different concept designs were first mentioned by its eventual designer in the 1991 reference book Star Trek: The Next Generation Technical Manual (pp. 177-187), where it was supposed to be a successor of the  starship as the next primary explorer ship of Starfleet. Years later, the Nova-class idea was revitalized, though this time for an altogether different purpose.

Design

The final design of the Nova-class starship model, as featured, was conceived by Rick Sternbach for "Equinox". It was based on the  Pathfinder design, whose top view was depicted in the Star Trek: Deep Space Nine Technical Manual (p. 122), the illustration of which was constructed in Adobe's Illustrator software by Doug Drexler. The Pathfinder was part of the background story in the Manual Sternbach devised to describe the design history of what was to become the . (Star Trek Voyager: A Celebration, p. 213) Sternbach, using tracing paper over the Defiant design for a basic sketch of the design, drew half a nacelle and half a ship body with a center-line which could be flop-copied. The sketch was turned over to Doug Drexler who produced the final drawing for the Manual. 

When asked to come up with a new design for a new small science vessel, Sternbach first considered doing a refit of the , but dismissed the idea since that design was over eighty years old. () He then recalled the design he had done for the Manual a year earlier, "The Nova class USS Equinox began as a small pencil drawing of a ship that was to have been the space-going equivalent of a PT boat in the Alpha and Beta Quadrant theaters. In the fictional history of the USS Defiant, as recorded in the DS9 Technical Manual, a fast and heavily armed "Borg Buster" with multiple torpedo launchers was modified with tucked-in engines and new ablative armor to fight the Cardassians, the Jem'Hadar, and the Dominion, among various other Alpha Quadrant baddies. The pathfinder form of that fast attack ship existed as a single top view until one day when the Voyager script "Equinox" appeared. It called for a new science vessel that had also been unceremoniously yanked into the Delta Quadrant by – guess who – the Caretaker."  Sternbach devised a background story elaborating on the history he had done for the Manual where the shelved Pathfinder hull design was re-appraised by the ASDB (Advanced Starship Design Bureau, the name Sternbach came up with to signify the research and development arm of Starfleet) for it to become the Nova-class. He submitted the idea and a copy of the Pathfinder drawing to supervising producer Peter Lauritson, who gave his approval thereby affirming that "the Defiant pathfinder was definitely the origin of the Equinox, in production as well as in non-canon backstory." 

On fine-tuning the design, Sternbach remarked:
"The design followed the basic Starfleet plan of a forward hull, engineering hull, and nacelles on pylons, though most of the shapes were given sharper edges and angles. I incorporated some stylistic elements from John Eaves' Enterprise-E as a possible ASDB "sibling", particularly in the pylon plasma flush vents and Bussard collectors. I also gave a tip o' the hat to Todd Guenther with the notching of the forward hull, a feature he employed in his home grown volumes Ships of the Star Fleet. The design cycle was almost as complex as that for Voyager herself, with ortho preliminaries and final blueprints, and perspective line art and detail sketches. The phaser strips were redesigned. I continued the trend of giving some Starfleet ships a large shuttle-like embedded craft, as Andy Probert did with the captain's yacht on the Enterprise-D, John Eaves did on Enterprise-E, and I did with the Aeroshuttle on Voyager.

The arrow-shaped craft on the Equinox underside is a hypersonic "waverider" shuttle, a highly fuel-efficient vehicle at Mach 5 and above. Tim Earls, a set designer on Voyager and a veteran of Babylon 5 and later Serenity, contributed a preliminary set of elevation views that helped nail the overall mass of the vessel and the creation of the cutaway graphic." 

More windows were added to the Pathfinder design, along with a new exterior bridge design. The Pathfinder design featured two forward-facing torpedo tubes where the auxiliary deflector was to be located and were moved beside the deflector in Sternbach's Nova. (Although Star Trek: Starship Spotter (p. 37) lists the Nova as having only two torpedo launchers, the design probably has at least three because the Equinox fired an aft torpedo in "Equinox, Part II".) Sternbach also envisioned the Equinox of having landing capabilities akin to the , "The three door-like things are retracted landing feet, yep. The other objects are RCS, as you surmised. On the CG render there seems to be a half-round V-shaped dimensional "fence" on the waverider belly, which is probably just an interpretation of a soft break in the belly shape in the blueprint. Not my doing, but I'll accept it as some type of structural reinforcement or active boundary layer controller."

CGI models

In  Sternbach's design received final approval from the effects supervisors and the design was sent to Digital Muse, where Eddie Robison built and animated the model in the  software. Robison kept in contact with Sternbach during the build in order to iron out detailing and the finished ship was a very close approximation to the design as conceived. "The CG model was initially built pristine, and then the textures were altered to look burnt and broken. From what I've seen in LightWave, you can subdivide a group of polygons where, say, you want to make it appear that a phaser hit has smashed away bits of the hull plating, and remove or distort those polygons until they look twisted, vaporized, and so on. Some of the digital modelling tools are quite remarkable.", Sternbach further noted. ()

Initially, the proposed starship designed to appear in "Endgame", was to be an entirely new design conceived by Tim Earls in . It was ultimately decided that the VFX team adapt the similarly designed model of the Equinox to fulfill the role of what would eventually be known as the Rhode Island. (Star Trek Voyager: A Celebration, p. 211)

This "refit" Nova-class design featured many changes, performance or visual-wise. Additions include a dome added to the bridge, impulse engines combined to one reactor on deck 1, and its auxiliary deflector reduced greatly and triangular-shaped. The gap in front of it is filled in. Portions of the Bussard collectors were covered by hull plating and the dorsal intercoolers were reduced to one on each warp nacelle from two. Finally, the ship's escape pods were replaced with pods from the . Modifications and remapping were done by Robert Bonchune at Foundation Imaging who remarked, "I did not come up with the name, but was allowed to come up with the NCC number and do whatever I liked to the shape. I always liked the ship, kind of like a small corvette Starship and I figured in a future time it would have been smoothed out and more organic. I also tried to tie it in to the Enterprise-E (or a Standard Starship) in some ways in terms of smoothness and escape hatches, intercoolers etc. I tried to make her look like she was moving fast and slick even standing still. I was going to make other changes to the bottom, but ran out of time for the show. (One reason why I shot her in the scenes from the top as much as possible) We had SO much to do on that finally, it was mind boggling!"  Unlike with the Intrepid-class, for which Bonchune built the Aeroshuttle, the waverider was not further explored: "I don't remember doing the shuttle for it. I know I did some textures and such, but not the design/model itself." 

Conceived well into the CGI age, no physical production model was ever constructed of the design.

Appendices

Further reading 
 "Designing the U.S.S. Equinox", , 
 Star Trek: Starship Spotter, 2001

External links 
 
 

Studio models