In the Next Generation episode A Fistful of Datas Worf is able to build a personal shield out of a telegraph machine and a standard issue communicator. Although Worf says it is highly unstable and won't last more than fifteen seconds, this is likely due more to the limited tools, technology and time that Worf had available to build it with than to the concept itself.

Once off the holodeck, why doesn't Worf or Starfleet research and developed a proper personal shield for personnel to use? It would make sense to have as standard equipment, stored right next to the hand phasers for away teams or supplied to troops deployed in a war. Even if it could only absorb a single shot before failing, that's still better than nothing.

  • Huzzah, seriously!
    – eidylon
    Apr 17, 2014 at 22:06
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    Because plot devices require that people get phasered and stunned constantly.
    – Caimen
    Apr 17, 2014 at 22:12
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    @Richard Not an exact duplicate. Asking why Starfleet doesn't have any is not quite the same as asking why they don't wear any. Also, the answer to that question is a bit antithesis to the mission statement of Starfleet, that is, to the peaceful exploration of space. Many times have characters had to state that the phasers are defensive weapons only. An outstanding personal shield and no weapon would be a better way to show your defensive nature, rather than no shield and a weapon that can vaporize people.
    – Xantec
    Apr 17, 2014 at 22:24
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    It's routine for Trek episodes to invent some new technology and then forget all about it the next episode. I think questions about such things are generally unanswerable without wild retconning speculation or just admitting that there's some seriously sloppy writing going on.
    – Kyle Jones
    Apr 17, 2014 at 23:13
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    They'll need to be careful; a slow blade will penetrate the shield.
    – asawyer
    Apr 18, 2014 at 22:09

1 Answer 1


They do have them, in large numbers. They just don't generally use them because...erm...mumbles incoherently

In DS9 : Homefront, there's mention that there are sufficient on Earth to equip an entire army;

"LEYTON: Mister President, we can use the Lakota's transporters and communications system to mobilise every Starfleet officer on Earth in less than twelve hours. We've been preparing for something like this for a long time. We have stockpiles of phaser rifles, personal forcefields, photon grenades, enough to equip an entire army. I can start getting men on the streets immediately.

JARESH-INYO: What you're asking me to do is declare martial law.

I think we can reasonably assume from Jaresh Inyo's instantly negative response that using personal shields is anathema to the Federation's principles of peace and viewed as the first step on the road to a police state.

On top of that, there's no real evidence that they'd be especially useful. There's a passing reference in DS9: "Business as Usual" that the sort of hand-held particle weapons that can be openly purchased would easily overmatch the sort of protection offered by a small personal shield

QUARK : The Breen CRM-one-fourteen works equally well against moving vessels or surface emplacements. It's guaranteed to cut through reactive armor in the six-to-fifteen centimeter range, and shields up to four-point-six gigajoules.

Admittedly this weapon is a very serious (and expensive) piece of kit, but I think we can presume that other races' standard particle weapons would be able to produce at least a reasonable fraction of this figure. Since the energy output of a communicator-sized battery would be tiny in comparison, the shield would be next to useless.

Breen CRM-114

Having said all that, we do see some applications of personal shield technology in Star Trek : The Animated Series, with the use of shield-based portable life-support systems. These are only used a couple of times but the principle seems solid;

portable life-support systems

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    So they do have them then. I never caught on to that blip in the Homefront episode. Seems odd, however, that an organization claiming to be peaceful explorers of space go out of their way to be as aggressive as possible when exploring on foot (i.e. carrying weapons that can disintegrate objects but no defensive tools or apparatus).
    – Xantec
    Apr 17, 2014 at 22:30
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    Also, I'd wager that Jaresh-Inyo's response was more towards deploying troops on the street rather than to those troops wearing personal forcefields.
    – Xantec
    Apr 17, 2014 at 22:33
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    That device was probably to save money in animation costs for the cartoon. The old series had no such thing when they needed to go in space, and the movies also ignored them.
    – Oldcat
    Apr 17, 2014 at 22:35
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    @xantec - The UFPs phasers are set to "stun" as standard. Isn't that defensive enough for you?
    – Valorum
    Apr 17, 2014 at 22:41
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    @Richard It is difficult to impossible to know what kind of gear would be needed to generate a personal shield of 4.6 gigajoules. As for a communicator sized battery, I'm sure the troops on AR-558 wouldn't have minded wearing a belt or small backpack with more capacity.
    – Xantec
    Apr 17, 2014 at 22:51

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