The Galaxy class starship was designed with the ability to separate the saucer from the stardrive section, so that the “floating city” part of the ship could be left somewhere safe while the rest of the ship galavants off to do something risky. We see this happen precisely once, in the season one episode Arsenal of Freedom. We also see saucer separation deployed for a handful of tactical and or emergency uses (such as against the Borg in The Best of Both Worlds, or to escape the breaching warp core in Generations).

So, this seems like a useful ability to have, and the Enterprise is constantly being sent into dangerous situations. Why not use this ability more frequently?

  • I think the saucer separation ability was an example of theoretical thinking. The Galaxy class designers clearly intended a use for it. In dangerous times, the saucer would separate leaving the stardrive section free to act without it.

    But, via practical real world experience, Starfleet learned that separating the saucer section was seldom worth it. It was too slow, where danger tends to occurred suddenly, and, even when there was extra time, Galaxy captains learnt the extra power generation of the saucer proved more useful than the decrease in mass. I doubt the War Galaxys from the Dominion War even had the ability and, if they did, it was only because it would take too much work to remove.

    It’s possible that the saucer section worked better as a one-use ‘super-lifepod’ but the original plan of combining and transforming ships clearly didn’t pan out. Same thing seems to have happened with the Prometheus with Starfleet deciding the ‘wolf pack’ attack mode innovations, while effective, are better implemented via separate ships. Like we see a trio of Texas class ships doing to take down a Sovereign.

    (There’s clearly some guy in the Starfleet bureau of ship design who keeps trying to make combining/separating ships happen and keeps getting disappointed when they don’t pan out in practice.)

  • From a real world perspective, I think they just found it slowed down storytelling too much. I think the idea originally came from Gene Roddenberry and they had always been trying to make it work.

    Ironically in Best of Both Worlds, it’s a lure to distract the Borg from the rescue mission, and it wasn’t like they offloaded the kids and civilians first. Pretty high stakes gamble on Riker’s part.

  • Do we know if it is really used infrequently, or does it just happen that it is not used during the events pictured on screen? There is no dialog where a character claims that it is used infrequently?

      • A lot of the focus here seems to be on the military utility, which is also how I suppose the separation feature was presented in the show.

        But an obvious use case would probably have been less dramatic. Anytime two things needed to be done at the same time. Send the drive section to the more distant or dangerous location and keep the saucer where it’s safer, like running supplies or something for a planet.

        Don’t know it would have been good TV though?! Perhaps if it was used as a plot device to put the ship in trouble?

        • @maegul @williams_482 I think it would actually be good TV for Lower Decks. A California class might have to visit a Galaxy class saucer that has been left in orbit for a month managing a research expedition or a conference, while the stardrive section got delayed hunting a Romulan warbird.
          It just wouldn’t be good television for a show set on a Galaxy class ship. The only way to do a “split ship” show would probably be to mainly follow characters on only one half.

        • That’s a fair point. The utility of the saucer as a separate craft doing different jobs is pretty limited though, which is another reason why we might not see it in day-to-day operations. There is only so much a 600m disc with no warp drive can accomplish on it’s own.

          • It’s the no warp thing that really limits its ability. The saucer can 1. limp back home. or 2. stay put while the rest of the ship does something risky and then hope they don’t have to resort to number 1.

            I could see the saucer section being left in orbit to assist with evacuations while the stardrive section “goes for help” but even this seems like a bit situational.

            • It’s not just the lack of warp that presents a problem. It’s the lack of power generation. If I remember correctly, and I’ll admit I may be misremembering, but isn’t the bulk of the Ent-D’s energy generation done by the warp core as well? So if the saucer is separated, any heavy power use (i.e. the main phaser array, heavy transporter use, etc.) is going to require the saucer to eventually link back up to refresh it’s power reserves lest they end up in a Voyager power rationing situation.

              Edit: This same point is what drives me crazy when I see the separated warp nacelles in DSC. If the ship loses power for any reason, the nacelles are going to float away which just adds to the list of problems to solve when getting the ship back under way. Also, if there’s a momentary power interruption to the beam emitters holding the nacelles in place, what’s to stop them from launching off like warp-powered torpedoes?