Designing the Phase II Enterprise

When time came to upgrade the famed Enterprise for a second television show, Gene Roddenberry asked Matt Jefferies to have another go at his starship to reflect the refit that would be part of the series’ backstory.

In his redesign, Jefferies changed the engine nacelles from tubes to thin, flat-sided modules and tapered their supports. He also added the distinctive photon torpedo ports on the “neck” between the saucer and the engineering hull.

“Basically,” Jefferies said years later, “what I did to it was change the power units and make a slight change in the struts that supported them.”

I gave the main hull a taper, then I went flat sided and thin with the power units, rather than keeping the cylindrical shape. Trying to work out the logic of the refit, I knew a lot of the equipment inside would change but I didn’t see that there would be any need to change the exterior of the saucer. Certainly, though, the engines would be a primary thing to change. Part of the theory of the ship’s design in the first place was that we didn’t know what these powerful things were or how devastating it would be if anything went awry so that’s why we kept them away from the crew. And that meant they could be easily changed if you had to replace one.

A model of the refit Enterprise was built by Don Loos, who had built the original ship more than ten years earlier.

When Paramount abandoned its plans for Star Trek: Phase II and decided to make a motion picture instead, Loos’ Enterprise was packed away. Director Robert Wise brought in a new art director, Richard Taylor, who assigned Andrew Probert to do a second redesign of the ship, essentially keeping with Jefferies’ new lines while adding the extensive detail that was necessary for a motion-picture miniature.


This Enterprise that wasn’t has always intrigued me. Jefferies designs were always so grounded in reality that it was a joy to see his ideas. The refit has always left us scratching our heads wondering if its even possible or practical to refit a ship to look so different. Would have been great to see the PII built as planned.

Steve (Jun 17, 2012)


Let me tell you something that MAY make your day…

I made virtually the same comment to Andrew Probert on YouTube. I said words to the effect that Gene Roddenberry was a romantic and they’re not the most practical of people. There is NO WAY you can call the TMP Refit Enterprise the SAME ship as the TOS TV era starship with so little surviving/being recycled!

To sum up, Probert agreed with me. The Enterprise in TMP should NEVER have connected/said to have been the ship we say on TV in the 1960s! It’s too different design-wise!

The other thing is that in real life, you would NEVER reconstruct a ship like that! Tearing a ship down carefully and rebuilding generally costs more than building a new ship from scratch. Real-life case: there were proposals to turn the test-vehicle, OV-101 Enterprise (currently sitting on top of the USS Intrepid in New York City), into a space-worthy shuttle, but they got shot down at least twice because it was cheaper to take spare parts and fashion new vehicles from those! To rebuild Enterprise as a full-fledged would have meant taking it completely apart and sending pieces back to at least a dozen major subcontractors to get pieces remanufactured to flight specifications. Everybody knows how expensive shipping is, right? Have you ever tried to MOVE from one house out-of-state into another state and take ALL your stuff with you? You generally can’t economically which is why a LOT of people only take the pieces (furniture) they absolutely want to keep because it’s cheaper to buy NEW furniture than move all the old stuff!

The space shuttle design changed dramatically between OV-101 and OV-102 Columbia… You were literally talking two different vehicles — one good for atmospheric testing only (gliding, runway tests) and the other for the full flight regime of a shuttle. It just wasn’t in the cards to retrofit Enterprise when there easier, cheaper ways to get a new flight-worthy shuttle on two occasions (to augment the fleet following Columbia’s flight test program and to replace Challenger after 1986).

There have been fansites claiming that things like the fictional Enterprise refit have been done in real life, but it’s total B.S.! Those articles are written by fanboys who have no personal knowledge of the true history of naval reconstruction… i.e., they do NOT rebuild/refit warships from top to bottom! What they DO is strip off the top layers and retrofit as much newer technology as is practical (and economical — BIG POINT!). When they modernized the World War II carriers that stayed into service through the 1970s, 1980s and early 1990s, they reconstructed the flight deck and upper hangar areas, BUT they generally left the rest of those ships alone! They had the same power plants, same hull, same crew compartments, etc., etc. that they launched with. It’s more of a “frankensteining” of old components with practical new pieces.

skull1986 (Oct 2, 2016)

What about WWII ships that were refitted in the 1980s? They were pretty much torn down to the their super structures (and modify it as well) and rebuild, but they are still considered the same ship.

GeekFiilter (Jan 10, 2017)

We’re talking about the upper decks or reconfiguring of the island, catapults, and elevators being altered — that’s all superstructure.

The main hull below the hangar deck of the carrier basically didn’t get touched… It was the superstructure of the older ships (mainly carriers we’re talking about here — but also applies to battleship reconfigs with regards to changes in weaponry) that was altered.

Those old ships (Essex-class and Midway-class carriers) were still operating with their original engines and boilers, BUT now with the upgrades and changes to the superstructure they maybe had somewhat reduced speed and even stability issues in heavy seas created by the overhang of the new angled decks. They DID have hurricane bows (enclosures) installed to keep heavy seas from spilling into the main hull. That was directly a consequence of the remodelled flight decks. These carriers were originally built with straight decks, but because of issues with jet aircraft handling and their higher landing weights and higher approach and landing speeds the flight deck area HAD to be radically rebuilt and enlarged. The USS Midway which is used as an example of a “real-life” equivalent to the Enterprise refit — which it’s NOT; it’s completely different than what was done to the NCC-1701 which was a keel to bridge redesign, tear-down, and new build — had horrible stability issues because of its revised flight deck. It was also considered underpowered, because the ship grew roughly 12,000 tons past the original gross tonnage! Again, below the hangar deck, the Midway is basically the World War II ship with the original engines. Whoever wrote that upgrade article comparing the Enterprise refit with the Midway’s refit in the late 1960s has no idea what he’s talking about. He’s no engineer, that’s for sure!

What happened with these World War II carriers was a far less severe upgrade than what the Enterprise went through for Star Trek: The Motion Picture.

For the Enterprise refit, the original Constitution-class ship was torn down to its bones — literally the original framework. All the wiring, hull plating, you name it had to be torn off and replaced with newer wiring and equipment. There could have been VERY LITTLE of the framework that was recycled because of the changes in the layout of the decks and overall shape of the hulls and connecting dorsal pylons. The connecting dorsals on the backs of the engineering hull are VERY different from the sweepback of the nacelle struts to the thickness of the saucer pylon and all the equipment that ran through and dotted the surface of the “neck”… Everybody recognizes the torpedo bays from the outside on the refit… What about all the changes in the neck on the inside for not only the torpedo bay loading, BUT the docking ports that were added to the exterior of the neck as well as the vertical warp core chamber that ran from near the keel of the ship to below the impulse deflection crystal? Those are huge, huge changes!

The shape of the engineering hull itself became a vat-shape versus the cone ship it had in TOS. The layout of engineering and the shuttle and cargo bays on the refit are completely different from the TOS Enterprise… For goodness’ sake, the refit Enterprise had an open cargo storage area connected with the shuttlebay in the The Motion Picture! The Enterprise-A had a little bit different shuttlebay, but it’s possible the refit (both Enterprise and Enterprise-A) had a dividing door/bulkhead that came up and sealed the main cargo area from the shuttlebay when they weren’t running in supplies for long-duration/critical missions.

The saucer was extended in diameter at least 40, maybe even 50 feet, which accounts for the majority of the growth in length of the refit design. The refit was about 1000ft long versus 947ft for the original Constitution-class configuration.

I can’t see how it would have been very practical to recycle much of the original Enterprise into the refit considering the deck layout changes, all the technology upgrades seen in the first movie… Maybe they could remelt and reform the metals and composites used to build the original but recycling and reusing this raw material doesn’t make the new ship the old one, either.

Gene Roddenberry was a romantic dreamer, not a practical engineer or designer. That’s something people have to understand.

People had the same arguments with that I’m presenting here when they were in pre-production for Star Trek: Phase II and Star Trek: The Motion Picture.

Richard Taylor, the main head of design for The Motion Picture, had some drag-out arguments with Gene Roddenberry, because Taylor was more practical and wanted a spaceship that looked more like something people would use in real life versus the fantasy world of Gene Roddenberry. Taylor didn’t understand at first that he had to make his customer happy instead of designing according to how he (Taylor) thought they should be. Andrew Probert got along better with Roddenberry because he understood he had to make Roddenberry happy first, which is why he was invited to work on Star Trek: The Next Generation and assigned the job of designing the Enterprise-D. Probert didn’t agree with Roddenberry on every little detail, but he did agree on the general aesthetics of starship design at least as far as Star Trek and the Federation were concerned.

Roddenberry insisted on the refit being THE Enterprise we saw on TV screens in the 1960s WITH THE SAME HULL NUMBER despite the impracticalities. The Enterprise design that Ralph McQuarrie submitted for an earlier Star Trek: Motion Picture looked very little like the 1960s Enterprise and was clearly an altogether different ship; it looked more a Federation star destroyer!

The most telling line in Star Trek: The Motion Picture about the refit Enterprise is one by Decker. He tells Kirk this practically an entirely NEW Enterprise, it was NOT the ship he commanded on a five-year mission. That should have sunk into people’s heads but it hasn’t for most of them — unless they work with cars and class car restoration. They would totally understand the points I’m trying to make here.

The Phase II design Matt Jefferies fashioned was a LOGICAL progression of the 1960s Enterprise with a large reuse of the original saucer (but STILL extended and with twin turbolifts connected to the bridge this time) and the main external deflector dish positioned closer to the hull in some interpretations of that design. (The Phase II model was never finished, so we’ll never entirely understand how it was supposed to look in the end. Modelers always change some things and make additions to the design plans they’re given to work from.) You could argue on whether or not the engineering hull on the Phase II refit was a remodel of the original or a replacement hull (I never saw a finished interior/deck schematics for the engineering hull of the Phase II Enterprise so I can’t make a definite conclusion there just by appearance alone). BUT the saucer was clearly original equipment just as the nacelles and their struts were clearly new hardware. The Phase II Enterprise, big changes to the nacelles and struts aside, can be regarded as the same ship that was seen in TOS.

If you really want to see a real-life equivalent to what happened with the Enterprise and its motion-picture refit, the best one I can think of off the top of my head is the DSV-2 Alvin, the submersible that was used to explore the Titanic in 1986. That submersible originally launched in 1964. However, because of technology upgrades and rebuilds there is no part from the originally built Alvin that’s still in use! Everything from the original Alvin has been replaced AT LEAST twice, which also includes the pressure sphere the operators and observers are crammed in during dives. These upgrades and equipment removals/new installations were mostly gradual (done over the years) and NOT done all at once because of a limited budget to maintain and support the mini-sub. The pressure sphere on the completely REBUILT, REDESIGNED Alvin in service is the third one installed in a submersible CALLED DSV-2 Alvin. In essence, the 1964 Alvin exists only in spirit, despite the reuse of the name and hull number on the currently operational submersible called Alvin. Appearance-wise, Alvin has also changed a bit. It’s a MUCH heavier and slightly bulkier submersible than the 1964 model. Maybe thinking of it as a new model/car design is better than thinking of it as a rebuild of the original 1964 mini-sub. It’s less confusing that way…

skull1986 (Jan 11, 2017)

As someone who has studied the history of navel engineering and refits, some are more extensive than others and some construction methods led themselves more it it than others. Modern navy ships are welded steel and don’t lend themselves to changing the hull. Though they have changed the bow on some ships by cutting off the old one. And there have been some cruise ships that have been extended by cutting them in half and inserting a new piece.

But the closest structurally to the starship design we see (remember we get a peak under the hull plating in Star Trek III) are the old wooden ships. With that design the hull plating and the hull structure are sperate elements and you can strip off the hull plating/planking and replace it and in the process you could change the frames to change the shape of the ship in the process. While in general wooden ships were rebuilt as close to the original as possible, the fact remains that during a complete replanking the design could be changed. And if you think they have never replaced that much of a ship’s frame, USS Constitution had that much replaced in 1928. The goal was to keep her looking the same.

In Star Trek we are provided the information that the 1701-D took ten years to build. Assuming for a smaller ship like 1701 might take five years to build and that we are told that the refit took eighteen months, we can assume two things: the refit was mostly cosmetic and underneath the shiny new hull lies the same framework, and that it was accomplished much faster than building a new ship. And as the Federation doesn’t use money like we do today, we can’t really judge the cost.

So all in all, the argument that this could not be the same ship underneath the fancy new exterior has so many holes in it that we could drive V’ger through them.

Mark Breuer (Mar 24, 2021)

Another example would be the USS Enterprise (CVN-65) after it’s refit between the late 70s and early 80s its design changed. The most noticeable differences were the removal of the large phased array radars and the ‘bee-hive’ radome from the island. So functionally it was the same ship with newer technologies and cosmetic changes.

Jeff Mulgrew (Aug 11, 2020)

Jeffries’ Phase II is one of my favorite Star Trek designs of all time. It’s the ship we should have seen on screen. I’m not even sure that Star Trek wouldn’t have benefited from that 70s TV series more than the movies that we actually got.

The Phase II Enterprise was refitted with essentially the same technology, and probably would have had about the same capabilities as the Constitution II (TMP) Enterprise. Later in the series with the Phase II decommissioned or destroyed, they could have introduced the TMP ship as Enterprise-A, and it would have been believable as the next-generation Constitution ship built from the kill up with the newer technology. That’s the way I think it should have been.

While they’re doing all this reimagining of this Star Trek universe, that is a concept I would have liked to have seen brought back. I think it would be cool if they ever did a remastering of the first few films like they did with the TOS TV series, to put the face to Enterprise back in the first three films. Then have it replaced by a “A” as I suggested. Now there’s a concept to chew on!

Gary H. (Dec 30, 2020)

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