Mainly the doctor's mobile emitter - they obviously have some rules about not disturbing the timeline via the temporal time directive by leaving advanced technology in the past, so why would they on the other hand accept and continue to use advanced technology from the future?

Wouldn't that be some sort of violation of the Temporal Prime Directive? Or do their restrictions apply only to pre-warp civilizations, like the normal Prime Directive?

The mobile emitter

I am not suggesting that they give it to anyone else, but rather why don't they destroy it? Or simply not use it and store it away somewhere? Or, out-of-universe, is it like the One Ring, and they can't destroy it nor help but use it?

  • 3
    The wilder the west the looser the laws, though the second question should be split into its own question.
    – Tritium21
    Commented Nov 12, 2014 at 3:04
  • @Tritium21 - I think your right, although the answer to that may very well depend on the answer to the first, so I will hold off on that for a bit Commented Nov 12, 2014 at 3:06
  • Actually, they are pretty well independent - to wit, i would vote down an answer that links the two.
    – Tritium21
    Commented Nov 12, 2014 at 3:07
  • It may dpend on how advanced the future tech is. The mobile holo emitter is just a refinement of existing tech, not something embodying totally new principles.
    – Joe L.
    Commented Nov 12, 2014 at 3:54
  • @JoeL. - the technology in this case is 400-500 years ahead of its time, and quite advanced - we are talking roughly going from a room-sized computer with vacuum tubes to a modern smart-watch, with all the extra bells and whistles that come along with it, in addition to the improved basic functionality. Commented Nov 12, 2014 at 4:23

4 Answers 4


The Temporal Prime Directive does not classify 1996 as the future

The only logical explanation that does not include the crew willfully breaking Starfleet regulations is a loophole based on how the technology was acquired. The mobile emitter was not a technology that they took from the 29'th century, nor was it established that the device itself is from the 29'th century. They got it from 1996, from a man who has... engineered all modern technology from a downed time-vehicle. It is very possible that the device itself was manufactured in 1996. Rejecting use of the device on that basis, would also require them to reject all other technologies developed since.

This answer (along with the episode from which the entire problem erupts) leaves a really bad taste in my mouth, but it is the one that logically follows.

  • 2
    Sounds like them twisting the rules to me - but I agree, it's the best answer other than "they decided to break the rules"
    – Liath
    Commented Nov 12, 2014 at 9:28
  • 1
    Janeway doesn't seem to care as much for the Prime Directive(s) as other captains when it blocks her from getting Voyager home, especially when it comes to the Temporal Prime Directive. The finale is proof enough of that.
    – Brian S
    Commented Nov 12, 2014 at 15:34
  • The Temporal Prime Directive is about maintaining the integrity of the timeline, but once tech starts moving along the timeline, it doesn't matter when the tech IS, it matters where the tech is FROM. Commented Nov 12, 2014 at 16:46
  • 3
    Look, we are dealing with writers creating existential problems to make a character less interesting. This is not something easily explained.
    – Tritium21
    Commented Nov 12, 2014 at 16:47
  • @BrianS - I'm pretty sure Janeway uses the line "Temporal mechanics gives me a headache" more than once as well.
    – Robotnik
    Commented Jan 22, 2015 at 4:54

In the novel 'Star Trek: Department of Temporal Investigations: Watching the Clock', Janeway has a brief conversation about the mobile emitter. It would seem that while 29th Century tech is advanced, the underlying principles aren't all that and a bag of chips.

“On Stardate 50312, you allowed your Emergency Medical Hologram to keep a mobile holo-emitter based on twenty-ninth-century technology, rather than confiscating and destroying that technology.”

“The Doctor needed that mobility to be able to do his job at peak efficiency. I couldn’t risk having my ship’s only medical officer trapped in sickbay indefinitely.”

“And didn’t you think about the consequences to Federation technological progress once you got back?”

“Frequently. But I studied the device. Whatever century it came from, its operating principles weren’t too far ahead of the current state of the art. I expected that by the time we got home, probably decades in the future, the technology would already have caught up.”


The device may have been allowed to be returned to the VOY timeline because its constituent components may have already existed in the timeline back in Federation space and the research was already being done. Or something more sinister...

There are a couple of reasons the Federation Timeship allowed Voyager to keep the holographic doctor's mobile emitter:

  • If the tech was already available and sitting in a development center or skunk works, the future Federation may have deemed it an acceptable risk, considering how far Voyager was from home. The technology would already exist by the time Voyager made it home. Since they are from the future, they may already know this to be true and allow it to "be noted in the logs and records."

  • A less savory alternative exists: Knowing the future, The Timeship crew may have decided the mobile emitter was necessary for Voyager to survive to reach Federation space and complete their mission. They may have conceded it was the least invasive/temporally-intrusive way they could contribute to Voyager getting home. The Doctor and his emitter have saved the day more than once.

Either way, giving the device to Voyager would definitely be considered tampering with the timeline, given that the mobile emitter was capable of compressing the holodeck technology and an unknown, inexhaustible but highly compatible power supply into something you could carry in your pocket, wasn't radioactive and could power the holoemitter for two years of use.


Always thought with the information that in the 31th century they fight a Temporal cold war that it's like with every war nothing is as it was before.

Why do we believe the Temporal Agents of the Future are protecting the very original timeline? Since the Federation prevails they must have kind of won the war. But as all factions of that temporal war messed with the past to give their faction an advantage and the enemy an disadvantage, I believe the timeline which is protected is not the original one but the one which brought the federation to victory. And we basically don't know which events fall under that timeline.

In first Contact the Enterprise helped to build the first Warp drive since that was what should happen or should it? Did Cochrane invent the Warp drive or was it actually Laforge? Or maybe Laforge build only a slightly better one which paced up the development of the Warp drive in the Federation. Also in Voyager we get to know that a lost Timeship was reverse engineered to develop microchips in the 20th century which had been the past for Voyager already. That was not corrected? Because it is also the past of the future Agents but not of the first timeline. In which all that must have happened much slower.

So my guess is basically that some Temporal Events were tolerated or even willingly guided by the future War Federation to come out on top of all that temporal fighting and then those Events are seen as the correct new timeline which must be secured to ensure victory of the Federation for all times. And maybe the point of Voyager bringing home Future Tech and giving the Federation a huge Tech boost is how it should be and just seems not right to us who always think the Future guys want preserve an unalternated timeline.

  • your facts are a little off. In ST: First Contact (the movie), LaForge and company simply repair the Phoenix warp ship, they don't build it themselves Commented Aug 17, 2019 at 13:48

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