A possibility that just occurred to me as to the reason why Archer wouldn't have mentioned the breaking of the Warp Four barrier separately in "First Flight" (ENT) is that it could have actually happened after construction on Enterprise had already begun, but before she was finished enough for engine trials, and thus still not yet "capable of Warp Four" herself. And this simultaneously could be a reason why he might not have been personally involved there, because he was busy supervising the construction, and considered it a bit of a sideshow. Or maybe he just knew that was part of "the rest" that T'Pol was already aware of. Maybe a lot of things. -MMoM
The idea that breaking Warp Four would warrant a mention is a bit odd to start with - indeed, in a story exclusively about breaking Warp Three, why does any other aviation accomplishment require a mention? Wouldn't it be actually counterproductive to the story? "We struggled so hard to cross the Channel. Oh, and then Alcock and Brown crossed the Atlantic." Kind of takes the accomplishment out of the accomplishment. Personally, I don't see the Franklin as an engine testbed back when she was first built, because she doesn't look like the part at all - not in comparison with the warp testbed we did see, that is. But her breaking Warp Four could still be a record for the record's sake, a "Let's see if we can do this - oops, we broke the ship and probably can't fix her until, oh, 2161 or so" thing rather than a performance spec that would allow her to move like NX-01 across the galaxy. Timo Saloniemi
[post moved to avoid double] Also, she need never "break" (i.e. exceed) Warp Four at all to satisfy the terms of Scotty's statement. She may have only just hit Warp Four momentarily during an engine trial as a fluke that could never be duplicated. Heck, as long as she'd done that much beforehand, she need not even have been operational during ENT's first season, only later being pulled out of mothballs and donated to the MACOs to play around with, or hastily pressed into service for the Romulan Wars. -MMoM
The broader thing here is that Starfleet in ENT clearly had lots of ships. Every time Starfleet chose to field NX-01 or NX-02 and deemed others unsuited, it was all about their Warp Five performance. It's not as if adding the Franklin would be in any way different from adding the Intrepid or the Republic or the Saratoga, then. Their one common defining factor would be "not Warp Five", which would automatically cover all the bases, no speculation needed. What "Warp Five" really entails is a separate question, one we may approach from the established datapoint of "not Warp Five" not sufficing for these known mission types. Being able to break a record is unlikely to be relevant there. Being able to sustain warp 4.5 for weeks may be the key - a ship of Franklin or Intrepid ilk might struggle to sustain warp 2, even if the former can briefly hit warp 4 and the latter warp 3.14 or whatever. A repeatable dash speed of warp 4 wouldn't "harm" the Franklin here. It just wouldn't amount to Warp Five. But we may indeed additionally speculate that her being able to do warp four doesn't amount to Warp Four in practice. Timo Saloniemi
Even holding Warp Four for 12 hours doesn't accomplish too much. The engines might require a lot of maintenance after that, or a lot of cool down time before trying again. Meaning you could be either doing spurts of Warp Four for half a day followed by being stopped for repairs, or forced to slow down to Warp Two or Three while the engines got retuned for the next Warp Four burst of twelve hours. if she can make Warp Three between her spurts of Warp Four, the equivalent if around Warp 3.5, but probably hard on the engine. With Warp Two between spurts, she's down to Warp 3.3 equivalency. With her having to stop between spurts, she effectively can make Warp 3.2, which is about half the speed of Warp 4, and thus take twice as long to reach its destination as if she made Warp Four the whole way....and four times the time as Enterprise maintaining Warp Five the whole way, which by her third year of operation, Enterprise could sustain Warp Five for almost two months without stopping, possibly longer, save her destination was reached. By her fourth year in service, she was refit to allow her to make Warp 5.2. And while that doesn't seem like much, if one follows the Warp Factor cubed system, that's just over 140 times the speed of light rather than 125 times the speed of light. And even if one doesn't follow the cubed scale, but go for a rough equivalency, that's still a reasonable improvement (if using non-speed of plot numbers, that is 6 weeks to Vulcans at Warp 5.2 rather than 7 weeks to Vulcan at Warp 5).
And it only gets more severe if one observes the actual onscreen speeds: warp five can accomplish half-a-dozen-lightyears-within-episode during Season 3, in basically every Expanse adventure. Since the lower end of the warp scale supposedly (although not canonically!) is always fixed at warp 1 = lightspeed, the gap between warps 4 and 5 grows when the higher observed performance of warp 5 is accounted for. Timo Saloniemi
Back then the general idea seemed to be that Warp 5 was a massive leap over anything that had gone before, and everyone else was trundling around at warp 2.something. If it was only an incremental upgrade, NX's capabilities as a deep-space explorer would seem to be less of a big deal. That said, Franklin exists now. So we could assume there were a few more ships from immediately before NX, such as Intrepid, that could do warp 4. Or alternatively perhaps Franklin and her engine was some sort of one-off. If multiple warp 4 ships existed, you'd think someone would have already gone to check out the situation at Terra Nova...
You probably have the wrong definition of "back then" there. Warp five was supposed to be a big leap back when the warp five project was launched, which was almost half a century before the warp five engine was actually built. When NX-01 finally sailed in 2151, warp five was still fine for deep space exploration, but we have no reason to think it would stand particularly far apart from other engines of the day. If Earth was developing warp five, obviously it would reach warp three and four in the meantime, and apply those to its fleet of ships. Its Starfleet, that is. Boomers would get their w3 refits only when they visited home, which might not be for years. If they could afford it. Not going to Terra Nova or other places was not dependent on engine performance as much as it was on Vulcan attitudes. Earth could easily have visited Terra Nova even at warp one if it really wanted. Except for the Vulcans saying no to pretty much everything related to deep space and especially the risks therein (one of which had claimed the colony). Vulcan ships could have been there and back in a jiffy, too, but Terra Nova was a planet forbidden. Heck, the only reason Archer was able to go anywhere was because he managed to fool the Vulcans into allowing him to make the taxi gig to Klingon space, and then failed to return. His warp five engine wasn't crucial there, and warp four could probably have worked just as well. All that said, w5 probably still is a quantum leap over w4. Just like w6 is over w5, and like w3 was over w2. Timo Saloniemi
No one really acts as if, from the standpoint of 2151, it was considered a matter of any great urgency or importance to find out what happened to Terra Nova in the episode. It had been seventy years since last contact, which itself had basically consisted of the colonists saying "fuck off Earth, we're fine on our own, and we'll shoot the first one of ye who trespasses here!" It was an intriguing mystery of some interest to historians and of particular personal fascination to Travis. It wasn't a priority. T'Pol seemed to imply that the Vulcans would have checked up on it for them if they'd only asked, and Archer replies that it wasn't considered worth whatever strings might come attached to the favor. Earthers were simply too proud and not interested enough. While Terra Nova may have been the only known Earth-like planet available for colonization within twenty light-years at the time of its discovery, there's nothing to say other more-attractive alternatives weren't discovered thereafter. Is there? -MMoM
Mind you that any newer drive than warp 2 would be only a few years old when Enterprise is commissioned. We don't know if Intrepid is older than Enterprise, or was launched while Enterprise was away on mission. The other vessels seem older, but Intrepid seems to be a contemporary, meaning it could be the previous class of starship, or it was designed as a parallel companion project ship. The Enterprise designed for exploration while Intrepid was designed for hunting pirates. Intrepid could have a warp five engine, a warp four engine, or a warp three engine. It might have a warp two engine, but it seem reasonable to have it with a better drive.
Since it wasn't said in the episode, we of course need not consider it binding, but FWIW the script of "The Expanse" specified that the Intrepid and the Delta were Warp Two ships. -MMoM
Standing far apart from everything else is sort of the whole point of the hero ship of this particular tv series. My guess would be there could be a few other ships capable of warp 4. But it's not yet particularly common. If there was a small fleet of Franklins, I find it hard to believe there would be no interest in finding out what happened to earth's first extrasolar colony. Intrepid could be anywhere from an old-school warp 2 plodder, to a Franklin-powered warp 4 ship, to a warp 5 ship that's actually newer than NX-01. Tho as mentioned above, the writers intent was for it to be old generation.
Even if Earth had completed NX-02 through NX-47 in 2151, only the one ship that managed to escape the Vulcans would get to experience these adventures. Why she stands apart from the rest is simple: she refused to return to Earth from her Klingon sortie. At that point, Vulcans could still have dragged her home, but by the time of "Breaking the Ice", they had apparently given up on that. Of course, with a mightier fleet of ships, properly equipped with phased death rays rather than plasma peashooters, Earth might be more capable of ignoring Vulcan "wishes". So we can't readily postulate a mighty armada of warp 4 and warp 3 vessels tugging on their leashes, unless we also assume that Earth's parity weapons were a new thing in the 2150s. Or at least that those weapons were sitting in warehouses while the starships had nicely modular gun berths currently equipped with water pistols, waiting for the political winds to change. Timo Saloniemi
NX-01 pretty clearly stands apart because of capabilities that notably exceeded those of previous earth ships. I know vulcans were exerting a lot of pressure on earth to stay at home, but i don't recall the threat of them intercepting and shooting at deep space explorers...
Yet that's pretty much what they would have to have been doing. Otherwise, Earth would simply pay a Boomer to go have a look at Terra Nova, or launch a government-operated warp 1.2 vessel to do so. We know it doesn't take a warp five engine to go to deep space. But all of ENT shows that if you also want to make noise and come back alive, you better have at least a warp five engine, transporters and phasers, and preferably shields and photon torpedoes as well. Perhaps Earth was held back not by (veiled) threats, but by the Vulcans convincingly arguing (and Earthlings not being too stupid to disbelieve) that there was this threshold of technology for deep space exploration, rather than a nice gradient that Earth could climb? Timo Saloniemi