How does Picard, or anyone for that matter, decide at what warp speed to travel? Obviously there are times when they need to get somewhere in a hurry and he says, warp 9 or maximum warp, but the rest of the time he just seems to pick a number at random. He rolls a warp 6.5 Is there some guide as to recommended speeds that he's following? Is there a speed that is the most efficient?

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    I've seen a number of episodes where it is suggested that various levels of warp can only be sustained for a given amounts of time. I can't think of any specifics off-hand, which is why this is not an answer.
    – Chad Levy
    Commented Oct 20, 2011 at 18:22
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    TNG Season 6 Episode 20, The Chase. In a Captain's Log Picard says "Our frequent use of high warp over the last few days has overextended the propulsion systems. We are finishing minor repairs before returning to Federation space." Just watched it. Good episode. :D
    – user19783
    Commented Nov 20, 2013 at 16:06
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    I'm a bit late to the party here, but one more thing to consider: At one point during TNG, they discovered that travel at high warp factors was damaging the fabric of spacetime, and if the damage got too severe, extremely dangerous subspace rifts could form. To minimize any future damage, the Federation Council restricted warp travel within certain at-risk regions of space to essential travel only, and limited all warp travel to a maximum of warp factor 5, except in cases of extreme emergencies. Later R&D in warp theory and design included attempts to mitigate this problem, resulting first i
    – user43374
    Commented Mar 22, 2015 at 6:01
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    @SilverlightPony That was in the final season, and was pretty much immediately ignored within TNG itself (there were a few nominal references to it, all regarding how they're totally going to ignore it now). This was given a slapdash resolution in Voyager, where altering nacelle positions after warp field activation altered the warp field geometry in a way which made it non-damaging. There was also a minor story where they were accosted by a species living in a weak region of spacetime. Commented Sep 15, 2015 at 5:26

3 Answers 3


One major consideration when determining the what warp factor to travel at is energy consumption: starships—even in the 24th century—did not have infinitely renewable sources of energy, requiring massive amounts of deuterium and antideuterium to power the matter/antimatter reaction assembly in the warp core.

A second consideration is the wear and tear on the warp drive: starships, for all their sophistication, are also fine-tuned instruments that will fail under stress, especially under the strain of sustained travel at high warp.

The final consideration, that you touched upon, is the urgency of the matter at hand. The captain must take the previous considerations into account and weigh them on the pressing urgency of the current mission.

So when a starship is commissioned, it's rated for different types of travel:

  • Normal cruising speed until fuel exhaustion. On a Galaxy-class starship like the Enterprise-D, this would be Warp 6.
  • Maximum cruising speed. Traveling at this speed would be tremendously inefficient, but should cause minimal wear-and-tear. For Galaxy-class starships, this is Warp 9.2.
  • Maximum top speed. Traveling at this speed would be inefficient and would not be sustainable after 12 hours due to the damage it would cause to the propulsion system. Warp 9.6 on a Galaxy-class starship.

So when Picard commands Warp 6.5, he's not picking a number at random: he's considered the urgency of the mission and decided that it's worth traveling faster than the normal speeds to get to the destination.


  • In "Force of Nature", it's determined that high warp speeds harm the fabric of subspace, and the Federation issues a speed limit of Warp 5 unless in the case of a dire emergency. Naturally, Enterprise-D often broke or ignored that limit (episodes are rarely if ever about the non-emergency missions). By the time Voyager was commissioned, Starfleet was able to develop a warp system that overcame this problem by creating a substantial warp field (the movement of the nacelles).

  • A good engineer always knows how to push the engines beyond their rated speeds: it wouldn't be unheard of for the Enterprise-D to run consistently a notch or two above the rated speeds due to La Forge's engineering skill.

  • Source for the speeds is from the Star Trek: The Next Generation Technical Manual.

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    I don't have a link, but I remember reading in a few places that the reason for Voyager's nacelles shifting as it went into warp was part of the solution to the warp fields damaging subspace.
    – Tango
    Commented Oct 16, 2011 at 16:44
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    Important Note: When @Mark says "a little bit faster" we are talking hours or days, not minutes. Often the speed choice is deliberately slow to allow the crew R&R before the next mission.
    – DampeS8N
    Commented Oct 16, 2011 at 21:55
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    @TangoOversway, not stated anywhere that he does it for the extra time. But I am a team lead and know how important having a rested team is, and it would be difficult to justify sitting around in orbit for a day before contacting the people you came to see.
    – DampeS8N
    Commented Oct 17, 2011 at 0:44
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    Voyager was able to cross the galaxy without access to a Starbase. Even in the present day, our naval fleet can go their entire rated lives on their original fuel supply. There's a LOT of energy inherent in matter-antimatter reactions. Problems usually occur when you are dumping fuel in to push the ship as fast as it'll go; no system is completely efficient, so I'd bet that while Warp 9 is three times faster than Warp 6, it would take significantly more than three times the energy to create a level 9 warp field than a level 6
    – KeithS
    Commented Oct 18, 2011 at 23:22
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    “Deuterium gathering (trading, extraction, etc.) doesn't make a very good episode, but it was featured on Voyager in a few episodes” — well, Voyager was never shy about doing episodes about things that didn’t make good episodes! Commented Dec 7, 2012 at 13:02

There are almost certainly guidelines laid down for each class of ship regarding energy usage versus travel speed.

As no system is 100% efficient, there will be a law of diminishing returns when picking a warp number to travel at. For instance, Warp 6 under the original scale (it's easier) is approximately 216c. Warp 9 is approximately 729c. So, Warp 9 is approximately 3.375x faster than Warp 6. A system with even, say, 80% thermodynamic efficiency (only 20% lost to entropy) would have to put roughly 25% more energy in than it saw in returns, so travelling at Warp 9 would cost approximately 4.2 times as much energy as travelling Warp 6, for only 3 times the gain. And that's if the system is equally efficient through its performance envelope; usually entropy becomes a larger percentage of input as the amount of energy in the system increases, meaning it might cost 10 or even 20 times as much energy to travel at maximum warp than at the ships "cruising speed" (typically the speed at which the engine is most efficient).

So, the consideration is between speed and efficiency. The faster the Enterprise travels, the more often it will have to refuel, on a disproportionate scale to the number of light-years traveled. Other maintenance will be required more often as well; in the episode where the Enterprise undergoes a baryon sweep, the base engineers state that the Enterprise has travelled more distance (and acquired more harmful subatomic particles) in one year than most ships do in five. However, sometimes you simply have to travel as fast as the ship can take you (such as to drop Deanna Troi's mother off at the nearest starbase).

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    +1 for "sometimes you simply have to travel as fast as the ship can take you (such as to drop Deanna Troi's mother off at the nearest starbase)"! Commented Sep 15, 2015 at 6:16
  • @DanHenderson I was wondering who'd get that one; I remember an episode involving Tori's mother where the denumon has Picard instructing the helmsman to lay in a course to where they were taking her in the first place, and his speed instruction, somewhat reduced in volume, is "warp nine".
    – KeithS
    Commented Sep 18, 2015 at 19:12

I agree with the above answers, but I had a few other ideas of reasons not covered in the above that I thought I'd throw out there:

  1. Sometimes they are on a specific schedule but understand that there can be delays. If they are meeting the Cardassian ambassador somewhere that takes 1 week to get to at warp 9 and 2 weeks to get to at warp 6, they can leave 2 weeks before the event and cruise at warp 6, then if something comes up en route make up time "in the air" by going at a faster speed.
  2. They're a science vessel, so they're constantly running long-range and short-range scans, gathering data and looking for anomalies and such. It seems very likely to me that if they're just cruising around or they don't have to be anywhere any time soon, they just set the value at the fastest speed they can go while getting thorough scans of the area. Of course, maybe this is way off and you can't even run sensors from within a warp field.
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    Or even, combine them. I think I remember an episode where they are on their way somewhere, but stop to investigate an anomaly with the justification that they'll use a higher warp to arrive on time
    – Izkata
    Commented Feb 26, 2014 at 0:17

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