Khan set off the Genesis device during the battle against the Reliant. Kirk's first choice was to beam over and turn it off. When his son said that was a non-option, Kirk's second choice was to escape.

Spock: Admiral. Scanning an energy source on Reliant. A pattern I have never seen before.

David Marcus: It's the Genesis Wave.

James Kirk: What?

David Marcus: They're on a build-up to detonation.

James Kirk: How soon?

David Marcus: We coded four minutes.

James Kirk: We'll beam aboard and stop it.

David Marcus: You can't.

James Kirk: Scotty, we need warp speed in three minutes or we're all dead.

Kirk had four minutes in which he could have fired off photon torpedoes or phasers.

Why did he not try to destroy the Reliant and the Genesis Device?

Is this mentioned in the novelization or by the scriptwriters? I am also looking for answers from canon sources.

6 Answers 6


The countdown on the Genesis device is not like the timer on a bomb, where if the countdown is stopped before is reaches zero, nothing happens because the bomb has not been triggered. The Genesis Effect has started operating as soon as Khan activates the timer.

This is clear from several things that happen. You can see in the clip from the film that as Khan goes through the four-step activation process, the Device is progressively powered up.

However, when he finishes the last step (at 4:26) the Genesis Device starts to operate. The behavior of the device has changed. It's not just lighting up any more; it's outgassing as it runs.

Moreover, while the above argument, based on the appearance of the Device, is certainly not conclusive, the next scene definitively states that the Genesis Effect is active. On the Enterprise, Spock immediate detects that the Genesis Wave is already being emitted.

SPOCK: Admiral, scanning an energy source on Reliant, a pattern I've never seen before.
DAVID: It's the Genesis Wave!
KIRK: What?
DAVID: They're on a build up to detonation!
KIRK: How soon?
DAVID: We encoded four minutes.
KIRK: We'll beam aboard and stop it.
DAVID: You can't.

This indicates that the Genesis Effect is already active. Apparently, it takes time between the start of the effect and the sudden burst of new life (which the builders arranged to be about four minutes). In the meantime, although some of the Genesis energy involved is leaking out, the simplest explanation for what is happening is that the Genesis Device is creating and storing most of the energy, which will all be released at the time of "detonation."

What would happen if the Reliant, or the Genesis Device aboard the Reliant were physically destroyed? We don't know for sure, but that stored Genesis energy isn't just going to be obliterated. If the device is blown up half way through the countdown, maybe only half (or less) of the total intended energy will be released. However, even a half strength Genesis Effect would be more than sufficient to obliterate anything nearby, including the Enterprise. (On the other hand, an uncontrolled partially-powered Genesis Wave detonation might be more destructive than a controlled one. We just don't know.) But either way, the Enterprise needs to get out of the neighborhood, so the crew (with their ship in almost crippled condition) are not going to waste time on anything else, like a pointless salvo of torpedoes.


I think there's something you missed in David's dialog:

James Kirk: We'll beam aboard and stop it.

David Marcus: You can't.

Note that Kirk doesn't say "deactivate it" or "abort the countdown." He says "stop [the detonation]", so beaming over with a phaser in hand (or a dozen torpedoes in tow) is presumably on the table. And David, having no reason to discount these options, says that it's impossible. So I think it stands to reason from what we're told on screen that weapons won't prevent the detonation.

Pure speculation: it seems unlikely that the genesis device is indestructible, although given its complexity, it doesn't seem out of the question to me that the buildup to detonation involves some sort of subspace something-or-other that can't be affected by regular Federation weapons. Or, more likely, the weapons energy would simply trigger a premature detonation by destabilizing the device. After all--at the risk of injecting too much real science--the energy to transform an entire planet has to be stored somewhere.

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    In theory the Genesis device could have been beamed up and then left in the pattern buffer or beamed out with a wide field dispersion. But to be honest Wrath of Khan has a few flaws but im not personally worried about this one. We have to assume characters in universe have more information than we do. And assume those explain the plot holes. Nov 20, 2020 at 20:26
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    I'd assumed this was more likely to be a failure of communication. David Marcus is a scientist who worked on the creation of the device. The natural assumption of someone in that position is "beam aboard and stop it" is interpreted to mean "turn it off using some on-off capability that is designed into the mechanism". Such a person usually doesn't immediately think of "nuke it from orbit™" as an alternative method of turning something off, even though "nuke it from orbit™" is usually quite effective at stopping most things. OTOH, the device had plot armor, so it really didn't matter.
    – Makyen
    Nov 20, 2020 at 22:35
  • @Makyen On the other hand, since Marcus has a chip on his shoulder re: Kirk's "military" nature and credentials, maybe he does assume Kirk is going to blow the device up since (as far as Marcus is concerned) that's Kirk's solution to everything.
    – Cadence
    Nov 21, 2020 at 1:33
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    Not to mention (granted he hadn’t revealed it yet), David had used protomatter to take shortcuts to realize his vision sooner. Who knows what Kirk destroying the device right then and there could have caused. The destruction and the scale. If that thing had planetary-scale power, imagine what a wildcat explosion due to offensive measures would have caused. Nov 21, 2020 at 3:42
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    Kirk didn't specify whether he meant "deactivate the device" or "destroy the device" when said "beam aboard and stop it", so we don't know what he meant. Neither does David. The point is we don't know if David meant "you can't deactivate it" or "destroying it is pointless". There's just not enough into from the movie to say either way.
    – user89104
    Nov 23, 2020 at 5:38

The Genesis device was designed to release an enormous amount of unstable energy in a focused, controlled manner to generate a new living environment based on the specification of the design team.

The film already showed the effects of Stage 2 with the transformation of the Genesis cave.

Once the device was fully activated by Khan, attacking the device wouldn't have stopped the explosion, it would have stopped the control of the explosion. Likely a worse outcome.

Essentially, think of how a bomb-pumped x-ray laser works. The release of energy is effectively instantaneous. The energy is then captured and shaped for the desired purpose. If you try and interrupt the process, all you will get is an unshaped detonation and you would have lost an opportunity to escape the blast area.


The Enterprise was deliberately in the Mutara Nebula without warp capabilities or shields to trap the Reliant.

But while doing that allowed the Enterprise crew to leverage their real-world battle experience to defeat Khan’s two-dimensional thinking on one level, the Enterprise had actually trapped themselves on another situation that put them at risk.

Other than having some remaining shield capability — and perhaps a few photon torpedos and limited phasers (I think) — the Enterprise at that point in the film had utterly no warp capabilities.

By the time the decision you are talking about happens, the Enterprise was (deliberately) in the Mutara Nebula in an effort to trap the Reliant: Without warp or shields, both ships would be on somewhat equal combat footing.

Here is the pertinent part of the script; both emphasis is mine:

We see the Enterprise emerging from the dark side of Gamma Regula, where Reliant is now a moving blip.

KIRK (continuing): Uh oh.

SPOCK: She can out-run us and out-gun us. But there is the Mutara Nebula at 153 mark four.

KIRK (studies his console): Scotty, can we make it inside?

SPOCK: The energizer's bypassed like a Christmas tree -- so don't give me too many bumps.

KIRK: No promises, Mr. Scott. On your way.

SAAVIK: Trouble with the nebula, sir, is all that static discharge and gas clouds our tactical display. Visuals won't function and shields will be useless.

Kirk looks over the rims of his glasses at Spock; they smile with faint amusement.

SPOCK: What's sauce for the goose, Mr. Saavik. The odds will be even.

Thus destroying the Reliant in such close proximity to themselves — without any realistic level of shields or a clear escape path — would be way too risky.

The gamble Kirk was facing in the context of possibly destroying the Reliant was as follows:

  • Would the warp core on the Reliant explode and damage the Enterprise further?
  • Would any damage to the Reliant — full destruction or otherwise — cause the Genesis device to prematurely detonate with the Enterprise near by?

The decision Kirk had to make was somewhat a real life Kobayashi Maru scenario: A no win scenario.

Thus in the end — while Kirk cheated in Starfleet Academy when faced with the test — in this situation there was no escape as a leader. The only thing that saved him was trusting on his crew to do what they had to in an effort to escape. Which sadly meant that to save the ship, his longtime colleague and friend Spock had to sacrifice himself.

  • This iterates other info from the movie but doesn't answer the question. Why couldn't Kirk have attempted to destroy the Reliant and Genesis with a phaser or photon torpedo?
    – user89104
    Nov 23, 2020 at 5:42
  • “Why couldn't Kirk have attempted to destroy the Reliant and Genesis with a phaser or photon torpedo?” Because the risk of doing so is too high. Remember this movie began with a Starfleet training mission. A lot of actions in this film are based on wiser, older Starfleet officers making decisions novices would never make. Nov 23, 2020 at 11:23

I tend to think Buzz's answer is the correct one. Namely that the device contained two parts

  1. A reaction chamber
  2. Containment systems for the reaction chamber.

In other words, destroying Reliant would have destroyed the containment systems and released it instantly.

Buzz missed one of the strongest arguments for this, however: Carol Marcus' presentation (relevant part starts around 1:04).

You'll note two things here

  1. The Genesis device is shaped like a missile
  2. The demo shows the device being fired at a planet (with the Genesis effect taking place upon impact)

Since the device is human sized and we know humans can fit in torpedo casings (as Spock's body does), it's logical that the device would be turned on, loaded into a torpedo casing, and then fired at the target you want to terraform. The impact would destroy the device itself, allowing the building Genesis effect to do its thing.


Nice observation. I think you found a legitimate plot hole.

I don't think the

Genesis is too tough to be destroyed

is a good answer.

The informed audience, would know that nuclear weapons will not detonate if you destroy the missile or the ship that is launching the weapon. So, the audience should not easily accept the fact that Genesis cannot be destroyed.

The reality of our technology in the present is that the more exotic and powerful something is, the less robust or stable it is...therefore it is usually easy to send it out of whack and stop it from functioning.

As a plot device, I would more quickly accept the fact that the Enterprise was still damaged and used everything it could've already to put the Reliant into its current state and did not have any torpedoes or power remaining for phasers.

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    If the wave is building inside the weapon, then blowing it up could release the wave.
    – Valorum
    Nov 20, 2020 at 19:17
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    the main engines were down and they didn't have shields - given their proximity, a photon blast and blowing up the Reliant, even without taking the Genesis wave into account, may have been too risky
    – NKCampbell
    Nov 20, 2020 at 19:29
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    Pretending you know more about a fictional piece of futuristic scientific equipment, than the fictional person who invented it, is ridiculous. Nov 20, 2020 at 21:01
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    @SolomonSlow - I'll see your phaser and raise you protomatter ;)
    – NKCampbell
    Nov 20, 2020 at 21:58
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    @user134289 How do you know thermonuclear detonation is the right analogy? Perhaps it's like a steam turbine gathering steam, and if you take a potshot at it yes it will stop (because it has a catastrophic containment breach) but it will not do you a world of good (because you're in the way of that breach). If Genesis were explicitly using or compared to thermonuclear fusion that would be one thing, but we can't simply assume the paradigm holds true.
    – Cadence
    Nov 21, 2020 at 1:48

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