In the first TNG episode the saucer section is separated at warp speed. But how is that possible? Memory Alpha says that the saucer section quickly loses speed, but wouldn't it just drop out of warp as soon as it leaves the warp field (like it is shown to every time the warp drive fails or is deactivated)? And thus the stardrive section would just crash into it?

Also is it even possible for the saucer section to leave the warp field without harm? It would be partially at warp and partially not for some time.

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    i don't have any support for this guess, thus no answer, but i'd imagine that the shield grid of the saucer is capable of sustaining a small warp field for a short time. in the event of separation at warp the saucer would be able to maneuver at warp speed for a limited time before the warp field dissipated.
    – Xantec
    Commented Apr 26, 2011 at 20:38
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    @Xantec: Your answer sounds appropriately Science!y - it's likely what the writers would have gone with. Why not post it as an answer?
    – Jeff
    Commented Apr 26, 2011 at 20:46
  • @Jeff fair enough, i will :-)
    – Xantec
    Commented Apr 26, 2011 at 20:52
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  • I have wondered this myself - thought about it quite a bit.
    – user14952
    Commented Jul 13, 2013 at 17:52

8 Answers 8


I would imagine that the shield grid of the saucer is capable of sustaining a small warp field for a short time. In the event of separation at warp, the saucer would be able to manoeuvre at warp speed for a limited time before the warp field dissipated.

Alternately, I remember reading a long time ago that the torpedoes had devices in them that let them carry a warp bubble off of the ship's warp field, so that in the event they were fired at warp speed they would be able to accelerate away from the ship (and the ship wouldn't crash into them); perhaps the saucer uses something like this.

References from Memory Alpha

  • Saucer_separation#High-warp_situations

    Though highly unadvised, it was possible to separate the saucer from the stardrive section at high-warp velocities. Used by Jean-Luc Picard during the first encounter with the Q, the saucer was separated at a warp speed of 9.5. According to Data, it was highly impractical, but possible with no margin for error. The slightest mishap would have made this attempt deadly. It was also required to clear the saucer section from the stardrive section to ensure safety, because as soon as separation was over, the saucer section would start to lose speed, causing danger to the stardrive section. However, Picard was able to successfully separate the saucer in order to protect the families of the Enterprise from the immense power of Q. (TNG: "Encounter at Farpoint")

  • Photon_torpedo#Technical_Manuals

    The propulsion system of the torpedoes is a warp sustainer engine. The engine coils of the torpedo grab and hold a hand-off field from the launcher tube's sequential field induction coils. A miniature matter/antimatter fuel cell adds power to the hand-off field. When launched in warp flight, torpedo will continue to travel at warp, when launched at sublight, torpedo will travel at a high sublight speed, but will not cross the warp threshold. (pg. 129)

  • Both paras are actually the same idea just a different implementation. I believe it was more along the lines of the 2nd idea, because yes, the photons did definitely have this... though I remember not what the device was named.
    – eidylon
    Commented Apr 26, 2011 at 20:58
  • I heard about "Warp repeaters" in this context once, that may have been this.
    – Colen
    Commented Apr 26, 2011 at 23:55
  • i have updated my answer to include references
    – Xantec
    Commented Apr 27, 2011 at 16:44
  • ok that reference to the torpedo convinced me, thanks
    – suicide
    Commented Apr 30, 2011 at 17:49

I was invited in to pitch story ideas to Ron Moore at ST:TNG. Before pitching, Paramount sent me a number of documents on the series, including "Star Trek: The Next Generation Writers' Technical Manual, Fourth Season Edition" by Rick Sternbach and Mike Okuda. In other words, this is what every writer for the series was expected to follow in regards to technical issues.

On page 15, under "Battle Configuration (Saucer Sep)," there is a sub-section, "Saucer section (aka primary hull)" that states:

When separated from the battle section (which contains the warp drive), the Saucer section is incapable of warp speed. The saucer section does have its own set of impulse engines for slower-than-light travel, and it has a complete set of deflector shields and phaser banks. When separation occurs at warp speed, the residual warp fields can take several minutes to fully collapse, so the primary hull can "coast" for some distance before it goes sublight. Control of the saucer section is managed from the main bridge.

So, at least according to the guys making this stuff up, it has no way to maintain a warp field, but will coast in one from separation until the field dissipates.

  • I recall reading something similar to this in the Star Trek: The Next Generation Technical Manual.
    – Schwern
    Commented Jan 22, 2015 at 7:31
  • Uh, isn't that what I said I was quoting, @Schwern? I got that from the one the producers sent me when they invited me in to pitch to them.
    – Tango
    Commented Jan 23, 2015 at 19:41
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    You gave a different title, "Star Trek: The Next Generation Writers' Technical Manual, Fourth Season Edition" which I assume isn't available to the public. Just providing a source mere mortals can get their hands on. :) Carry on with your excellent answers!
    – Schwern
    Commented Jan 23, 2015 at 19:52
  • I think you're being a bit over-literal. Same writers - they basically just polished it up and made it spiffy so it would sell better. Also, I'm sure they refined it more each season as more questions arose, so the published version may have details added over the next 3 seasons.
    – Tango
    Commented Jan 25, 2015 at 21:49
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    This was mentioned on p. 28 of the published version of the TNG technical manual, where they say in saucer sep at warp speed, "decaying warp field energy" around the saucer would take about 2 minutes to "dissipate". Also illustrated in the TNG episode "Force of Nature", where there was a subspace rift and it would be dangerous to have warp engines on inside it, so Data suggested that they "initiate a brief, high intensity warp pulse" outside it and then "coast into the rift", but he noted "we should be able to sustain warp speed for approximately two minutes" before naturally dropping out.
    – Hypnosifl
    Commented Jun 1, 2019 at 1:12

I could have sworn that the ST:NG Technical manual claimed there were Warp Sustainers built into the saucer section to allow it to remain at warp after separation. Can't find my copy at the moment. If I remember correctly, at least some of the standard probe types do have warp sustainers, so they "exist" in the ST universe.

  • I seem to recall that too. There was a warp rating for a separated saucer section (Warp 6 I believe?). Claim of it being enough for it to operate as a lifeboat to get to nearby worlds if the main propulsion goes down. Unfortunately, I sold my tech manual a few years back... Commented Jan 23, 2012 at 18:21
  • This would make sense, since the saucer section catches up with the stardrive section at Farpoint, even though it traveled at maximum warp for at least 15 minutes (and possibly several days). Either would put it well outside the range of an impulse engine.
    – Peter
    Commented Jan 15, 2017 at 12:00

Firstly, the warp bubble extends beyond the Engineering section. They can modify it's size at will, and have done so on occasion to envelope other nearby objects, such as when they were trying to slow down that asteroid that was going to crash into that planet by enlarging the warp field around it.

Secondly, if there were any major ill effects from suddenly leaving the warp bubble, then every time the warp drive failed, the ship would be destroyed and/or heavily damaged, hence it must be possible to leave the warp bubble at will.

Now, I'm not sure how this next part would really effect it, but technically the ship never goes faster than .25c, which is full impulse. The Warp Drive is short for "Timewarp Drive". Basically, what it does is twist space to alter the flow of time inside the bubble such that they can move at 1/4th the speed of light and from the perspective from outside the bubble they are moving faster than light. Since the bubble moves with them, they maintain the speed from the outside observers point of view. Change how much you're bending space time and you change how fast you go relative to outside points.

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    Timewarp Drive? If how you describe it is accurate then how do they keep people on ships traveling at warp speed from aging faster than people not traveling at warp?
    – Xantec
    Commented Apr 27, 2011 at 16:08
  • Who says they don't? It might just be something they don't cover, after all, it's not hard sci-fi. It obviously can't be an Alcubierre type drive, as that would require two bubbles, one expanding space behind and another shrinking it in front of the ship. Maybe it's why the missions tend to be short, only a few years.
    – Phoenix
    Commented Apr 27, 2011 at 16:25
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    – Xantec
    Commented Apr 27, 2011 at 17:23
  • That doesn't fit with the explanations on Memory Alpha. Also the Alcubierre drive doesn't create 2 bubbles. It creates a single bubble that contains the ship, where the bubble is what actually moves faster than light so the ship riding the bubble isn't breaking any relativistic laws. Commented Dec 17, 2011 at 5:00

It's obviously possible for it to leave the field without harm - it occurred.

As for how it remained at warp, I believe the only explanation is the warp field being extended beyond the ship for some distance, within which the saucer could maneuver at warp speeds, before moving beyond it and dropping out of warp.

  • What about "shear" at the boundary of the warp field, though? I can't even fathom the amount of stress that would put on the hull. Commented Apr 26, 2011 at 20:40
  • The saucer can generate its own shield's, I believe. Perhaps that's enough. Or maybe they cross through fast enough to keep it from being too big an issue, given their hull strength.
    – Jeff
    Commented Apr 26, 2011 at 20:47

Isn't it possible they had a secondary warp core, like they had the battle bridge, the shuttles have small warp cores, etc.? It is conceivable that they have a smaller one that can sustain half of the ship, i.e. the saucer section, whereas the main warp core is required to run the entire ship.

  • Sure it is possible, but I don't remember any reference to it in any canon. But it certainly makes sense: if a shuttle can have warp drive, why not the saucer section? Commented Dec 24, 2011 at 16:08
  • The warp core is just a power plant. It's the nacelles that generate the warp field that accelerates the vessel. Think of it like some of the new hybrids that have an ICE, but their drivetrain is connected to an electric motor. The warp core would be the ICE. It's just charging the batteries and providing electricity for the electric motor. The electric motor is the actual propulsion system. Commented Dec 24, 2011 at 22:00
  • The nacelles don't have to stick out, they could be along the side of the saucer section.
    – aaa
    Commented Dec 25, 2011 at 22:04
  • Furthermore, It must be capable of warp drive (maybe limited as the second section was clearly faster) but still managed to warp to far point after meeting Q.
    – aaa
    Commented Dec 25, 2011 at 22:11

The USS Prometheus from Voyager split into three parts, two of the had two large warp nacelles and the saucer section had two small deployable warp 'stabilisers' which wouldn't allow to go into warp but allow the craft to maintain warp and exit it in a controlled fashion. It is possible that the saucer section of the Enterprise-D had a prototype version of this that allowed for a safe exit from warp.

  • Actually, that's incorrect. All 3 parts of the USS Prometheus featured Warp nacelles. The top end of the saucer had 1 hidden Warp nacelle at the very top (behind the bridge section) which extended during multi-vector assault mode. As for the Enterprise-D, the most common explanation is that the saucer section has the technology to maintain a Warp field for a certain amount of time (if separation occurs at Warp speed) and allow the saucer to safely departs from the stardrive section.
    – Deks
    Commented Jul 2, 2020 at 17:52

The warp field is a bubble around the ship. It does not propel the ship in the same manner as a rocket which pushes the vessel. Warp field shrinks space in front of the ship and expands it behind the ship. http://en.memory-alpha.org/wiki/Warp_field

Regardless of the propulsion method, if the separation occurred at any speed, so long as the main portion of the ship decelerated at a greater rate than the saucer this maneuver could easily be achieved.
https://en.wikipedia.org/wiki/Newton's_laws_of_motion https://en.wikipedia.org/wiki/Theory_of_relativity https://en.wikipedia.org/wiki/Special_relativity

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    Welcome to the site. Answers are typically expected to provide references / citations to relevant material backing up that answer. You simply make a statement with no references to Star Trek material to support it. Your answer probably won't fair well.
    – Stan
    Commented Jul 13, 2013 at 10:32
  • Added links for your pleasure. However, you did not choose to undermine answers above which contain no links to references. Why? Commented Jul 16, 2013 at 16:46
  • Your answer was in the 'first posts from new users' queue so I only looked at your answer and evaluated it in terms of what the site looks for in an answer. I did not evaluate it terms of any other answers. And I don't think I 'undermined' it, I simply asked for references that supported your statements. With that said, your answer provides no support for how the saucer section can continue to be in warp once it's separated and that's the core question - 'How could the saucer section of the Enterprise sustain warp velocity without a warp engine?'
    – Stan
    Commented Jul 17, 2013 at 0:28
  • Well seeing as how warp is a bubble it is reasonable to see the saucer section, still within the bubble, can maintain warp speed since space is still shrinking in front of the saucer and expanding behind it as per the reference. Per the reference we already established that the nacelles create the bubble and the warp bubble moves the objects within it. The Nacelles do not push anything. And looking at actual theories of relativity, as I posted links to, the saucer wouldn't just instantly fall out of faster than light speeds as there isn't an opposing force acting on the saucer section. Commented Jul 17, 2013 at 19:42
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    You said "Warp field shrinks space in front of the ship and expands it behind the ship", but I don't see where your reference at en.memory-alpha.org/wiki/Warp_field actually states that, it says the drive "warps space around the ship", and the part at the bottom from the Technical Manual talks about layers of warp fields exerting "forces" on one another. It sounds like you are conflating Star Trek warp with the real-life theoretical proposal of an "Alcubierre drive" discussed at en.wikipedia.org/wiki/Alcubierre_drive
    – Hypnosifl
    Commented Feb 8, 2014 at 14:11

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