I remember a TNG episode where some scientists said that warp drives were causing a lot of damage to subspace. At the end of the episode Star Fleet decided that warp speeds would be restricted to warp 5 except for emergency situations.

Of course the next episode they were cruising along at warp 7.

Is this ever mentioned again in Star Trek?

  • 8
    The episode was Force of Nature Season 7 Episode 9. This article on Warp Field has a brief paragraph on the subject, both on Memory Alpha. Mar 17, 2011 at 23:01
  • 12
    Since when has a negative effect on the environment ever stopped anyone from driving faster? ;-)
    – Thomas
    Jun 26, 2011 at 18:02
  • 3
    I had always thought that the restriction was being placed upon regions of space that are more susceptible to damage, but I just re-watched the final scene in that episode and it certainly does appear to be a "global" speed limit. Huh.
    – Mike Boers
    May 5, 2012 at 1:11
  • 6
    @MikeBoers At the end of the episode, Captain Picard reads the Federation Council directive: "Until we can find a way to counteract the warp field effect, the Council feels our best course is to slow the damage as much as possible. Therefore, areas of space found susceptible to warp fields will be restricted to essential travel only, and effective immediately, all Federation vessels will be limited to a speed of – Warp 5? – except in cases of extreme emergency." The directive could be interpreted to mean only in "areas of space found susceptible to warp fields" is warp travel restricted.
    – RobertF
    Dec 22, 2013 at 3:11
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    The mechanism described by the brother and sister team - analogized by Data as "wearing out a carpet by walking on it over and over" - would never apply to any appreciable area of space, so the episode never made any sense in the first place. Between the sheer scale of interstellar space and the expansion of space itself, no warp field would ever be generated in the same section of space twice. Ever. Terrestrial environmental concerns don't work when applied to the scale of the galaxy.
    – tbrookside
    Aug 26, 2018 at 14:05

4 Answers 4


It was never addressed in canon.

The episode to which you refer, "Force of Nature", occurred in the last season of The Next Generation at a time when most of the effort in storylines was geared towards Star Trek: Voyager and Deep Space Nine: the developers of those shows didn't particularly focus too much on the continuity issues introduced as The Next Generation was wrapping up. Indeed, even The Next Generation writers ignored or found ways around it for the remainder of the season.

However, according to Memory Alpha:

According to the unpublished VOY Season 1 edition of the Star Trek: Voyager Technical Guide, by Rick Sternbach and Michael Okuda, it was suggested that because of the variable geometry pylons, warp fields may no longer have a negative impact on habitable worlds as established in this episode.

But since the manual was never published, it's not canon. Alternative theories include:

  • In Deep Space Nine, the Dominion War was more important than an environmental concern.
  • In Star Trek: Voyager, they were so far away from the Federation and getting home was such a huge priority, any non-core regulation artificially limiting their ability to travel was summarily dismissed.

It's also interesting to note that the issues raised in "Force of Nature" are referenced, indirectly, in the last season Voyager episode, "Renaissance Man", when the Hierarchy attempt to trick the Voyager crew into ejecting their warp core because they entered an area that's occupied by people who believe warp drives disrupt subspace.

  • 1
    It's also worth noting that TNG struggled over its run trying to move from an episodic series (which was Roddenberry's intention with TOS and TNG) into an ongoing continuity.
    – HorusKol
    Jun 27, 2013 at 0:40
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    In a nutshell "You must construct additional pylons"
    – IG_42
    Aug 24, 2015 at 17:28
  • @IG_42: LOL.... Jun 14, 2016 at 11:36
  • 2
    It is mentioned again in S07E12 at ~1:30. The enterprise is authorized to "exceed warp speed limitations for the duration of the assignment".
    – boot4life
    Oct 7, 2018 at 18:42

Early in the episode The Pegasus Picard is given orders to search for the titular ship. The admiral who gives him the order also gives him authorization to ignore the warp speed restriction, for the course of the mission. This episode was 3 episodes after Force of Nature, the episode where the 'speed limit' is introduced.

It was never mentioned during DS9. During VOY, they may have mentioned it during a couple of episodes where there are regions of space that are unsafe to traverse via Warp Drive (here and here), but I don't recall offhand.

  • Good catch, I remember it being mentioned but had little hope of finding which episode!
    – sanity
    Mar 18, 2011 at 4:56
  • I wonder, however, if warp above 5 is mentioned subsequent to Force of Nature without it being an emergency?
    – sanity
    Mar 18, 2011 at 4:57
  • 1
    I think they mentioned the limit (as in, "we're ignoring it on purpose") for the following 2 or 3 episodes, then dropped it.
    – benzado
    Mar 18, 2011 at 7:09
  • @sanity not sure what the emergency was, and unfortunately I don't have access to TNG season 7 to find out.
    – user1027
    Mar 18, 2011 at 9:52
  • 2
    It's also mentioned in passing in the episode Pegasus, when Picard is given authorization to exceed warp speed limitations "for the duration of this assignment". Aug 4, 2011 at 5:15

The short answer is that it's not addressed again, beyond the end of TNG.

In-universe explanation

Quoting from the Star Trek Encyclopedia (2nd Edition)

The council further ordered Federation ships throughout the galaxy to restrict their maximum speed to warp 4.7. (TNG: Force of Nature). The Starship Enterprise-D and other ships observed the "warp speed limit" for the remainder of Star Trek: The Next Generation. After that, it was assumed that Starfleet was able to develop a more "environmentally friendly" warp drive, so the speed limit was evidently lifted.

One can assume that if the fix was actually quite trivial, the other major powers would have had no qualms about enacting it.

Out of Universe explanation

As to why the decision was made to simply gloss over the problem, the simplest way to look at it is that continuing to insist upon 'warp-speed restrictions' would have demanded regular explanation (adding to the length of scripts) without actually improving them in any way.

As Ronald D. Moore stated in the Captains' Logs: The Unauthorized Complete Trek Voyages book:

...when you limit warp drive, the rug is being pulled out from under Star Trek.

  • ..."Out of Universe explanation" - which begs the question of why did they introduce it in the first place?
    – komodosp
    Feb 28 at 12:07
  • @komodosp - Because writers often write themselves in a corner without realising it. Luckily they can handwave these things away just as easily
    – Valorum
    Feb 28 at 15:13

They very clearly stated that warp speed was restricted in areas of space affected- it was never restricted across all areas of space. It is assumed that any time they say "authorized to exceed warp speed restrictions" it's because they're in an area of space affected by the rifts.

  • 1
    The affected area seems to be extensive and cover all of the Alpha and Beta Quadrant powers inclusing the Federation and its near neighbours such as the Klingons, Romulans, Ferengi, etc; memory-alpha.wikia.com/wiki/Speed_limit
    – Valorum
    Aug 25, 2018 at 23:04

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