Why are there cargo ships in the Star Trek stories?

With replicator technology and FTL communication, there is no need for cargo ships. You can just transmit the computer files on how to replicate just about any device.

Want your own Triumph motorcycle in your new colony at Procyon-B? Just have somebody back on Earth scan the device, send the files to you by subspace email, and then use your replicator to create an exact copy of the motorcycle.

Want a copy of the Mona Lisa? No problem! Just scan that too. Now you can mount a copy on your bedroom wall. It's picture perfect down to the molecules of paint.

Sending computer files by email sounds so much cheaper and safer than shipping items by freight. The market will go for the cheaper option.

  • 60
    Somebody needs to transport the replicators
    – Geneworm
    Commented Feb 11, 2019 at 7:41
  • 14
    Some beings like the authenticity of 'real / original' products rather than replicated ones. I think that argument comes up a few times in the series.
    – user107907
    Commented Feb 11, 2019 at 8:42
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    @Geneworm Only one. The others can be replicated.
    – Suthek
    Commented Feb 11, 2019 at 9:56
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    Why do you think replicators are cheaper than other industrial processes? Did we switch over to 3D printing the second it became available? No, we added it to our growing set of tools. Replicators have costs and limits, just like any other process. Given that spaceships are still built the old-fashioned way in space docks, it's obvious there's many things that can't be replicated economically (if at all). Even the replicators we see on the Galaxy are tiny, only useful for having your Earl Gray in the morning. They still have a chef :)
    – Luaan
    Commented Feb 11, 2019 at 15:18
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    @EricLippert Now imagine the effective bandwidth of a starship moving at warp 7, carrying boxes and boxes and boxes of memory cards... (sorry, isolinear chips)
    – user
    Commented Feb 11, 2019 at 20:46

3 Answers 3


According to this earlier answer, which quotes the TNG Technical Manual, replicators need raw materials.

For instance,

raw stock for food replicators is stored in the form of a sterilized organic particulate suspension that has been formulated to statistically require the least quantum manipulation to replicate most finished foodstuffs.

Hence, there is a need to transport raw materials as well as materials that the replicator can't replicate. Also, it may make sense to transport and store some common, much-used materials like water, fuel and metals rather than using energy to replicate them.

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    That would explain why you would need them aboard a ship, which has limited resources; however, the destination is usually a planet which has enormous amounts of matter and energy available.
    – DrSheldon
    Commented Feb 11, 2019 at 13:49
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    But sterilized organic particulate suspension is so tasty. ;)
    – T.J.L.
    Commented Feb 11, 2019 at 14:56
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    It's also often noted that many things simply cannot be replicated - really, the things that can be replicated are the exceptions, and they tend to be extremely simple. Food stuffs are relatively complex, but they also don't require a lot of precision. Things like warp coils are apparently way beyond the Federation's replication capacity during the shows. When we see Federation transports, a lot of them are ferrying things that aren't "replicable" - people, ores, raw materials, machinery, plasma, antimatter... The replicators really seem more a luxury item than anything else.
    – Luaan
    Commented Feb 11, 2019 at 15:12
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    @Luaan Replicator technlogy = (short range) transporter technology. As shown in the shows over the decades, they can transport sapient species and, complex computers, active antimatter containment jars on antigravity sleds, and armed photon torpedo warheads.
    – Lexible
    Commented Feb 11, 2019 at 17:06
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    @Luaan I believe at several points they also state that not everyone likes replicated things. Tom Paris in Voyager, as I recall, gripes that the replicators never really get tomato soup quite to his tastes. I think Worf and/or other Klingons say much the same about Bloodwine. So there's probably a sizable market for non-replicated foods and other items to meet people's preferences or technical requirements. And in DS9, Ben Sisko's dad runs a restaurant, which evidently cooks non-replicated food into non-replicated meals, and this is quite popular. Picard's from a farm, etc. Commented Feb 11, 2019 at 17:26

Replicators have certain limitations. They can't create:

  • Antimatter

  • Dilithium

  • Latinum

  • Living organism

As for the living organisms, Star Trek: The Next Generation Technical Manual states that:

Though the replicators use a form of transporter technology, it's at such a low resolution that creating living tissue is a physical impossibility.

As for the organic food replicator creates, organic raw materials are needed to be fed into replicator.

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    @jo1storm Or have lower energy requirements to produce the "normal" way - on a Starship, space is at a premium so Replicated is the way to go. But, on a Planet with lots of room for storage, Replicating things may be a waste of resources. Commented Feb 11, 2019 at 8:41
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    Can't food replicators create living gagh? I'm pretty sure I remember seeing gagh served live to visiting Klingons on a federation ship. These look like they might be alive although I can't see them moving.
    – terdon
    Commented Feb 11, 2019 at 11:55
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    Replicators can only create items appropriate to their size as well, as industrial replicators are a thing. Industrial replicators seem to be much smaller in numbers, and possibly limited access. memory-alpha.fandom.com/wiki/Industrial_replicator There also seem to be many non Federation civilizations that are space faring, but possibly do not have replicator technology.
    – Kai
    Commented Feb 11, 2019 at 12:43
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    @Chronocidal - "on a Starship, space is at a premium" - There is a joke there somewhere but I can't think of it. Commented Feb 11, 2019 at 20:50
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    Basically, the issue is that replicators are just lower-quality transporters, likely to save on maintenance costs due to wear-and-tear (because if a replicator is as accurate as a transporter, there's no reason for it to be a distinct device, so it's going to be used as often as a transporter, and then much, much more). So, lower-quality components are "good enough", which in turn leads to a resolution issue, that makes replicators the 720i to transporters' 4k HD. Commented Feb 12, 2019 at 8:06

Replicators are common on federation ships, but don't seem as available to other cultures, or independent / underground communities. This is government/military grade, top of the line technology you're talking about. There may be agreements to share some technology with allies, but it's not 'open source', so to speak.

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    Or replicators may require (for example) a high-power energy source such as a matter / antimatter reactor, which you would have available on a ship but may be incredibly expensive for a typical independent community. Commented Feb 11, 2019 at 23:29
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    I think there's a DS9 episode where Sisko talks about giving the Bajorans industrial grade replicators. He was concerned about the replicators being used to manufacture weapons. Clearly the use of replicators was something that had military applications so the Federation didn't want just anybody to have them. Maybe that is why many Federation colonies did not have industrial grade replicators.
    – RichS
    Commented Feb 12, 2019 at 5:50
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    My headcanon is that starships are wrapped around their power systems -- matter/antimatter reactors on Starfleet ships, controlled singularities on Romulan ships -- that produce enormous amounts of power required for warp drive. Such power plants are inherently dangerous, and so not used on inhabited planets, where a failure (however unlikely) would cause colossal devastation. So on a ship, power is plentiful but space is limited. Replicators take a lot of power, but not much space; you can feed a crew of a thousand with replicators more easily than you could feed a city of millions.
    – bgvaughan
    Commented Feb 12, 2019 at 21:51
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    @bgvaughan And even on space ships, they're more a luxury item than anything else - instead of military rations, the crew eats "fresh". Star Trek isn't entirely clear on where the antimatter for Starfleet ship comes from either - some stories suggest it is mined, others that it's produced on the ship itself due to the magic of dilithium (and dilithium itself is considered very valuable); but it's entirely possible it's produced at a net energy loss, and only used in spaceships because of its energy density (and possibly warp drive magic). Real rocket fuels are often the same way.
    – Luaan
    Commented Feb 13, 2019 at 10:58
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    @bgvaughan we see in ds9 that transporters and replicators are freely available on earth, so at least mega population centers have them. But we also see that people snob replicator food and will go to restaurants where they get something cooked.
    – Andrey
    Commented Feb 14, 2019 at 21:44

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