In the film First Contact, when in the past, the Borg from the future try to contact the Borg in the past's time period by building a transmitter out of the particle emitter on the main deflector dish. The particle emitter is detached from the deflector dish by Worf, Picard and Lieutenant Sean Hawk, and then blown up, to stop the Borg transmitting their message.

Now, fast forward to the end of the film - the crew of the Enterprise have to get back to the future, so Picard instructs whoever it is on the bridge to emit a reproduction of the inverse tachion pulse that opened the temporal vortex that the Borg sphere & the Enterprise went through to get back to the past at the near-beginning of the film.

My question is: With the particle emitter on the main deflector dish destroyed, how exactly did they emit this pulse? Do they carry spare particle emitters on board (doubtful - it's a pretty large piece of equipment to carry spares for), or did they construct a new one somehow? Or do they have a secondary deflector dish powerful enough to do the job? Or is it just a gaping plot hole?...

  • 3
    Arguing from Voyager, I'd say a starfleet crew can rebuild basically everything except the warp core in mid-space. But that's too bold a statement for a proper answer :)
    – bitmask
    Commented Apr 15, 2012 at 21:16
  • Well, Voyager was rather a unique ship, having to scrabble together anything they could to keep the ship running. Perhaps Picard used a similar trick to Janeway - utilised the Borg technology the Borg had installed on the Enterprise to rebuild a particle emitter?
    – Nick Shaw
    Commented Apr 16, 2012 at 9:03
  • Yes, possibly. But it's terribly far fetched, isn't it?
    – bitmask
    Commented Apr 16, 2012 at 12:06
  • 4
    Star Trek technical details "far fetched"? Surely not. :)
    – Nick Shaw
    Commented Apr 16, 2012 at 12:55
  • 3
    @NickShaw: Of course it is. And don't call me Shirley.
    – Jeff
    Commented Apr 16, 2012 at 13:35

2 Answers 2


I realize there's an accepted answer to this -- but the dialog in the last moments of the movie contains an answer to this which is apparently being overlooked.

They don't need the deflector dish; they modify the warp field to generate the chronometric particles.

PICARD: Report.

WORF: The moon's gravitational field obscured our warp signature. The Vulcans did not detect us.

LAFORGE: Captain, I've reconfigured our warp field to match the chronometric readings of the Borg sphere.

PICARD: Recreate the vortex, Commander.

LAFORGE: Aye sir.

RIKER: All decks report ready.

DATA: Helm standing by.

PICARD: Mister Data, lay in a course for the twenty-fourth century. I suspect our future is there waiting for us.

DATA (OC): Course laid in, sir.

PICARD: Make it so.

Typically the deflector dish is the "Do Impossible Stuff" fixture on the ship, but in this instance they don't claim to even need it.

  • Hmm, a very good point, @Stick. I think this definitively answers my original question. To follow up, this agrees with the early part of the film where the Borg originally create the vortex to the past: DATA: Sensors show chronometric particles emanating from the sphere. PICARD: They're creating a temporal vortex. RIKER: Time travel! (the Enterprise suffers a shockwave) PICARD: Data, report! DATA: We appear to be caught in a temporal wake.
    – Nick Shaw
    Commented Mar 26, 2014 at 11:16
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    Of course, moving at any 'decent' speed without a deflector dish would be highly dangerous - but I guess they wouldn't need to be going that fast to get back to Earth (of the future) and get proper repairs.
    – Nick Shaw
    Commented Mar 26, 2014 at 11:17
  • Yeah, it's one of those Very Important Parts that theoretically they couldn't really do without. I know that at least 'unofficially' there is a saucer deflector on Galaxy-class starships, so maybe Sovereign-class has one too, and they can muddle through with that guy until they reach Utopia Planitia for a new dish. And anyway, do they need one for warp? Ideally, theoretically, the ship is motionless in warp… eh, it's just a show, I should really just relax
    – Stick
    Commented Mar 26, 2014 at 13:55
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    They don't actually need anything outside of standard relativistic theory and their sublight engines. They can just accelerate their ship to the speed of light and coast for a few hundred years. The journey would appear instantaneous for the ship and its crew, but hundreds of years would pass for anyone not moving at relativistic speeds during that time.
    – aroth
    Commented Dec 7, 2015 at 3:55
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    @aroth The deflector dish would have been necessary to pull that off if they didn't want to turn into spacedust.
    – JAB
    Commented Mar 22, 2017 at 15:56

Most of the basic equipment that is used on these ships can be easily replicated. What they jettisoned was a dish made out of smaller regular components. It would have been trivial to replicate the parts if they didn't have them sitting around. And they easily could have had them sitting around. This piece of equipment has no direct backup and so it would be wise to carry at least some of the parts - especially any that can't be replicated - in one of the many storage compartments.

Remember. The enterprise is big. So big in fact that during the entire run of TNG you never see shuttle bay 1. You only see the MUCH smaller shuttle bays 2 and 3. The Enterprise-E in First Contact isn't as big as the -D from TNG, but it's still quite large.

As mentioned in the comments. The Enterprise did indeed have backup deflectors. I was working on the assumption that in order for time travel to remain a rare event, the maximal technology would need to be required to perform it. I'd say that it is reasonable that on a weakened part of space, the most powerful mobile deflector dish assembly on the most powerful ship in the fleet might be just enough to reopen the rift.

I always thought it would have been a nice nod if they got back by flying past warp 10 around the sun...

  • That's a good point, yes, they could have built a new one out of much smaller components, replicating bits they didn't have. I wonder, though, why it's called a "main" deflector dish - it implies there's a "secondary" deflector dish somewhere?
    – Nick Shaw
    Commented Apr 16, 2012 at 13:06
  • And of course, as we well know, they use the deflector dish to emit streams of particles of one type or another to get out of almost every situation they come across [in the TV episodes] - so perhaps such a vital piece of equipment DID have an entire working spare ready for swap-out.
    – Nick Shaw
    Commented Apr 16, 2012 at 13:08
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    It must of had multiple deflectors if capable of separation, only due to the fact the saucer needs it's own for safety during warp. It's not unlikely that a sovereign class wouldn't be able to do this even if it's only an emergency measure more like the constitution class refit.
    – ewanm89
    Commented Apr 19, 2012 at 22:45
  • Can the saucer section go to warp? It doesn't have warp nacelles. I thought it had impulse power only? It would still need the inertial dampers for full impulse power though, I guess.
    – Nick Shaw
    Commented Apr 26, 2012 at 15:27
  • The saucer on the Enterprise D couldn't go to warp. If the E could, I've never heard of it. Commented Jun 30, 2012 at 17:58

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