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The purpose of this article is to consider the photon torpedo load typically carried by Federation Starships and facilities, and to consider just how reasonable this load is.

The Original Series

During TOS, there is actually very little information given about photon torpedoes. Even the very nature of the weapons themselves is unknown – some of the behind the scenes material even indicates that they are not physical missiles at all but rather a cloud of matter and antimatter enclosed within a magnetic forcefield of some sort. If this were the case then the ship would be able to fire photon torpedoes for as long as the ship’s matter / antimatter fuel held out – there would be no concern over wasting the ammunition itself, only with having enough M/AM to shoot. But whilst this is plausible, it is never supported within an actual episode.

Star Trek II

Star Trek II is the first time we ever see a photon torpedo as an actual physical object, when we see them being loaded aboard the Enterprise. They are a rounded oblong shape, approximately 2 metres long somewhat under a metre across, and about half a metre tall. Just big enough, in fact, to serve as a coffin for Spock at the end of the film.

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This is our first indication that there must be limits on how many of these things a ship can carry because of the physical volume limitations. And indeed, the fact that the torpedo is lowered into the bay from above means that the Enterprise’s ammunition storage must be in the connecting neck between the saucer and engineering hull, which means it must be relatively small.

Star Trek VI

Star Trek VI gives us our first indication of how many torpedoes the Enterprise can carry. When the ship apparently fires two photons at Chancellor Gorkon’s cruiser, Kirk asks Scotty what is going on. Scotty checks some sort of log which shows this :

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As you can see, Scotty is looking at the “Weapons Data Bank”, with the page marked “Inventory Program : Photon Torpedo”. There are four columns of data here, each with 24 entries on it – a total of 96. This, then, may represent the photon torpedo load that the refit Constitution class carries. Of course, this is not certainly so. The screen does “fill up” with data as Scotty watches, and then begins to empty itself again. So possibly this is just “page one” of many pages of information. And for that matter, it’s pure assumption that each little entry on that page represents one photon torpedo. Still, this does seem to be a reasonable interpretation of the scene.

Later on Spock states that the ships databanks show that they did indeed fire torpedoes. He references another display on the bridge whilst making the claim :

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Again, the screen shows four columns totalling 96 bits of data. However, this time two of them are highlighted in red. The only reasonable interpretation is that these lines do indeed represent a photon each, with these two being the two that the Enterprise allegedly fired earlier on. Whilst it’s still possible that this is just one of an unknown number of pages, then, it seems very likely that the ship does indeed carry 96 torpedoes.

We are given no indication of how many photon torpedoes the Excelsior class may carry, though since it is a rather larger ship than the Constitution then we may safely assume that it carries more.

Deep Space Nine

In Deep Space Nine’s first episode, “Emissary”, we hear the following :

Kira : "All right, then, let's give them our answer. Fire six photon torpedoes across Jasad's bow."
O'Brien : "We only have six photons, Major."

Of course at this point DS9 has only just been taken over by the Federation and it’s hardly in top condition. These six presumably just happened to be the last few weapons that the Cardassians left behind or a token number that the Enterprise-D dropped off, rather than anything approaching a "normal load".

Kira also has the station establish false sensor readings of their weapons. When the Cardassians scan them, we are told :

Jasad : "What are their defences?"
Cardassian : "According to our scans, an estimated five thousand photons, integrated phaser banks on all levels."

The Cardassians are suitably impressed by this weapons load. Deep Space Nine carries about as many torpedoes as twenty Galaxy class ships!

Of course this was just an illusion. But in the later "Way of the Warrior", we would find that Starfleet had refitted DS9's weapons and that it did indeed now carry 5,000 photon torpedoes and many phaser banks. This was enough armament to stand against an entire Klingon battle fleet.

The Next Generation

Whilst TNG and beyond would introduce nomenclature indicating many different types of photon torpedo had come and gone, the same basic casing remained in use throughout. Here we see a TNG photon torpedo aboard the Enterprise :

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According to the TNG Technical Manual, the casing measures 2.1 x 0.76 x 0.45 metres. Whilst the manual is not canonical these figures do match up to what is seen on screen, so I will presume that they are accurate.

The Tech Manual also gives a figure of 275 as being the number “normally stored aboard the ship”. Which, again, is not canonical.

Whilst we never do actually see the weapons magazine of a galaxy class, we do get a canonical number for the photon torpedo loadout of the ship. It comes in the season five episode “Conundrum”. The crew have lost their memories and are trying to work out what kind of ship they are aboard. Worf access the computer and says :

Worf : "I have completed a survey of our tactical systems. We are equipped with ten phaser banks, two hundred and fifty photon torpedoes, and a high capacity shield grid."

This contradicts the TNG TM number. But of course, there is nothing to say that the ship is fully stocked at this point. We saw the Enterprise-D firing photon torpedoes on many occasions, and it’s certainly possible that their normal load is 275 and they happened to have 250 aboard on that particular day.

One of the things that is strange about these ships is the number of weapons they carry as compared to the rate at which they can fire them. We know that the Galaxy class can "burst fire" at least five torpedoes from a single tube simultaneously, as it does in "The Arsenal of Freedom" :

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The TNG Tech Manual indicates that up to ten can be fired in one burst like this, though I believe five is all we ever see on screen. But at this rate the ship could exhaust all of her ammunition in less than thirty bursts from each of the two main tubes.

Or then there is “Half a Life”, in which we see the ship launch five torpedoes in less than a second, followed by another equally rapid cluster a few seconds later :

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At an average rate of say three per second each, the two launchers of the Galaxy class could go through the entire ammunition stock in under 46 seconds.

Of course, this isn’t an error as such. It’s not uncommon for a weapon to be able to exhaust its ammunition rapidly - both a modern assault rifle and a modern fighter jet's cannon firing at their maximum rate will empty their ammunition supply in a few seconds or so. Naval ships generally have more endurance than that, but even they can usually shoot out their entire ammunition supply quite rapidly if they were ever to really let rip at the maximum possible rate of fire.

What I do find strange is that they have so little endurance when it would be so easy to have so much more... but we will discuss that later.


The USS Voyager is of the Intrepid class. Roughly half the length of a Galaxy class and thus approximately one eighth of the volume, the Intrepid class carries a small number of photons. We are told the following in "The Cloud" :

Chakotay : "We have a complement of thirty eight photon torpedoes at our disposal, Captain."
Janeway : "And no way to replace them after they're gone."

Thirty eight photons would be roughly in line with a ship that is about eight times smaller than a Galaxy class. Amusingly, over the course of the series the ship would go on to fire something like 120 torpedoes from their irreplaceable stock of 38. One can only imagine that they worked out a way to replace them after all.

Sci-Fi Writers Have No Sense of Scale

Here’s the thing about science fiction ships. They’re almost all mindboggling huge. It’s seldom realised just how big they are, even by the people who create and write about them. And I’m not just talking about the miles-long ships that populate many films. Star Trek ships are actually at the lower end of the scale for giant science fiction ships - yet the Galaxy class, for example, is almost absurdly huge.

Currently the largest warships in the world are the US Nimitz class Aircraft carriers. Each of these behemoths weighs in at a massive 100,000 tons, and has a total internal volume in the region of three hundred thousand cubic meters. Each has the facilities to house seventy or more modern fighter jets plus six thousand crew members, along with thousands of tons of fuel, supplies, weapons, etc. They have been compared to a small town floating on the sea.

In volume terms, a Galaxy class Starship is approximately fifteen times the size of a Nimitz class aircraft carrier.

But of course a Galaxy class is not an aircraft carrier. Perhaps a better comparison would be something like a modern missile warship, such as the Arleigh Burke class destroyers. These ships mass about eight thousand tons. Each has 96 missile launch cells – and whilst each of those normally holds a single missile, they can hold up to four smaller missiles, for a total load of 384.

And in volume terms, a Galaxy class Starship is approximately two hundred times the size of an Arleigh Burke class. If the armament scaled up in line, a GCS would be able to carry well over fifteen thousand missile/torpedoes.

It’s hard to illustrate just how absurdly under-armed Federation ships are for their size. Here's one approach.

I mentioned the dimensions of a standard photon torpedo earlier. Here is one put next to a person :

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Here’s the same guy standing next to a rack of ten photon torpedoes. As you can see, it’s a pretty tall rack. But it easily fits into a 3.5 meter tall deck, which is about the average deck height on a Galaxy class ship.

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Now how many of these racks could you fit on, oh, let’s say a basketball court? Let’s leave lots of space to get in and out, broad passageways that you can easily pull a torpedo out into so you can work on it if needed. There really seems little point in doing that, because with Trek Tech you could just beam any given torpedo casing out of the magazine to fiddle with it or load it or whatever. But let’s leave nice wide access spaces anyway, just to be really conservative. Even then, you can still easily fit 64 racks onto a basketball court :

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That’s 640 photon torpedo casings in that one room. Of course a basketball court is a rather large room, right? I mean, we see cargo bays and hangar decks and such in Starships, but you couldn’t have many such places on a ship, could you?

Well, here’s how many basketball courts you could fit on one single deck of a Galaxy class Starship :

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That’s right. Two hundred and fifty six of them, on that one deck of the saucer. Admittedly it is the largest deck of the saucer. Deck 10 would hold this many, as would Deck 9. Decks 8, 7, and 6 would easily be able to hold about 216 each.

So that’s five decks, with 1,160 basketball-sized rooms in them. And this leaves decks 1 through 5 and 11 through 15 of the saucer section completely untouched, along with the entire engineering hull. Still plenty of room for crew quarters and all that, although they wouldn’t be anywhere near as luxurious as those we see on the Enterprise-D. It would certainly leave the ship with several times as much room for crew quarters and amenities as the Constitution class had, for instance.

But let’s be ultra conservative. Let’s assume that each of those five decks loses a third of it’s torpedo magazines to space for the impulse engines, turbolift shafts, things like that. Let’s say that the total is actually a mere 600 basketball court sized rooms given over to torpedo stowage.

So. Even giving over two thirds of five decks of this 42 deck ship to magazine storage would give you the equivalent of 600 courts x 64 racks per court x 10 torpedo casings per rack... which means that conservatively, a Galaxy class could hold 384,400 photon torpedoes.

Three hundred and eighty thousand.

Remember Deep Space 9’s five thousand photon torpedoes? That was considered to be enough to make it a very tough target even for an entire fleet of Klingon warships. In truth, such a capacity is easily within the reach of even a modest ship. Here’s Voyager, with some of our Basketball sized Magazines placed behind each torpedo tube :

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That’s really quite a modest installation... two magazines behind each torpedo tube. As you can see, they take up a very small portion of two decks of the saucer, and a very small portion of two decks of the engineering hull. Fitted out like this Voyager would be virtually unaffected in terms of the volume given over to weapons... still plenty of space for luxurious crew quarters, holodecks and all that. Yet this fitting would allow the ship to carry 5,120 torpedoes. More than the heavily fortified and upgraded Deep Space Nine had.


It’s common to posit that the Federation doesn’t stock Starships up with large numbers of photons because they’re the good guys – these are not ships of war after all, but ships of diplomacy and exploration.

I think I’ve demonstrated above that this really isn’t a good explanation. Certainly I can see why Starfleet wouldn’t want to put three hundred thousand torpedoes into a galaxy class. It’s an easily achievable proposition, but at that level we are talking about giving over a good chunk of the ship’s volume to photon stowage. In an organisation that isn’t driven by combat capability, I can see why they would avoid it.

But five or ten thousand? That’s so vanishingly small compared to these ships that it’s absurd to suggest that unwillingness to commit the volume needed is the reason. And then there is the fact that Starfleet are not the only organisation out there. Let’s say that it is simple pacifism on their part. What stops the Klingons loading up their ships like this? What stops the Romulans doing it? The Cardassians? All of them employ ships that could comfortably take tens of thousands of torpedoes in even a small fraction of their volume. Yet apparently, they never do.

In the end, it comes down to the way these things are depicted. Producers and art departments love their giant ships, because it makes for an impressive visual image that speaks of power and awesomeness. But nobody ever really follows through on what that would mean in terms of the capabilities. It’s not a great catastrophic flaw, but it’s always bugged me. Maybe now it will bug you too!

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© Graham & Ian Kennedy Page views : 86,772 Last updated : 18 Apr 2020