Could a light fighter (Mongoose Traveller core rulebook, p. 136) fit into the cargo zone of a Free Trader Type A (p. 117)?

If yes, how much cargo space will it use — its tonnage of 10 tons? Or more, as it's not a crate and doesn't neatly fit with other cargo?

I can't find any rules for small craft inside ships, but they are supposed to be designed to fit into larger ships. The main concern is that, if you look at the deck plans, it seems that the fighter will use a good amount of space, so a 10 ton small craft could end up using (let's say) 20 tons of effective cargo.

I appreciate RAW as well as DM / player experience.

  • 1
    \$\begingroup\$ If it helps, the section on small crafts specifies that they take up their tonnage in space - but also that they're in form-fitting alcoves rather than spacious landing bays, so presumably just chucking 'em in a cargo hold wouldn't be as efficient. \$\endgroup\$
    – GMJoe
    Nov 30, 2015 at 5:49
  • \$\begingroup\$ @AngeloFuchs With the release of Traveller 5 and MG Traveller 2 we're getting questions where the asker is assuming that saying "Traveller" is enough for us to know they mean T5 and/or MGT and/or MGT2. Basically, there are too many unclear possibilities now, so it's time that [traveller] stop being used to cover them all and start using tags that askers can easily find to make it clear which game they're asking about. \$\endgroup\$ Feb 15, 2016 at 18:11
  • \$\begingroup\$ @AngeloFuchs Of course, if you foresee a difficulty in that, please do let me/us know, perhaps by a meta about tagging Traveller questions! I'm just going ahead and changing things, but it's possible I'm overlooking something important. \$\endgroup\$ Feb 15, 2016 at 18:17
  • \$\begingroup\$ @SevenSidedDie I'm thinking about it. Don't worry, if I feel its important enough I'll bring it up :) \$\endgroup\$ Feb 15, 2016 at 18:21
  • \$\begingroup\$ @AngeloFuchs Thank you! I've tweaked the tag wiki to indicate that other tags should also be used where available. That just leaves a few Traveller games without dedicated tags, but they're the ones that I think askers will be quite explicit about which game they mean when they ask. \$\endgroup\$ Feb 15, 2016 at 18:22

3 Answers 3


For a reference, the Space Shuttle Orbiter, an atmospheric entry capable real-life spacecraft that weighs ~68 tons empty or ~110 tons loaded would need a hangar so big that it would store more than 3500 tons of cargo* if used as a warehouse. That's a ratio of 1:35.

This is assuming that your hangar is a plain box. If you customize your hangar to fit your atmospheric craft's geometry, I believe you could get significant savings, but it's still something like 1:20.

If you also optimize your craft and add features like folding wings and control surfaces (like on naval fighter jets on aircraft carriers) I believe it is possible to store and field 1 ton of spacecraft in the space needed for 10 tons of cargo. ie. 1:10

A real life cylindirical spacecraft like the Apollo command+service module is much more effective in that sense. It weighs ~12 tons and approximately fits in a cargo hold that could fit 36 tons if needed, for a ratio of 1:3. Keep in mind that it is a very frugal spacecraft with just 6 cubic meters of interior space for three astronauts.

By the way, 1:3 is also the ratio for a typical car.

The International Space Station is more like a distributed spacecraft, made up of connected modules, and in its assembled and deployed state, the same calculation gives a number more like 1:78

If I would make a ruling on this, based on hull configurations in the Traveller SRD, I'd go for 1:4 for standard, 1:16 for streamlined and 1:80 for distributed. If the daughter ship has provision for stowing or folding ptrousions like wings, radiators and solar arrays, I'd make the numbers 1:3, 1:8 and 1:20 respectively.


Zeiss Ikon mentioned the Traveller Classic rule about cargo space, standardised for liquid Hydrogen. If that is the weight/space ratio they had in mind (~75kg/m³), then my assumptions become something like this (rounded for simplicity):
2:3 for standard (1:1 stowed)
1:6 for streamlined (1:3 folded)
1:30 for distributed (2:15 stowed+folded)

* Assuming a 200kg/m³ average density as most cargo companies do today

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    \$\begingroup\$ When I played Traveller (what's now called Classic Traveller, this might have changed since), ship board space was measured in "standard tons" which were calculated at the density of liquid hydrogen (as for fusion fuel), appr. 13.5 cubic meters per ton. At that density, a Space Shuttle Orbiter at 68 T empty would be housed in 918 m^3, about half the size of that hangar (which, I might add, is quite a bit larger than it needs to be just to house the ship, in order to house equipment for servicing the dorsal payload bay). Seems to me that Traveller standard cargo space is about right. \$\endgroup\$
    – Zeiss Ikon
    Dec 23, 2015 at 12:04
  • \$\begingroup\$ @ZeissIkon Good detail, maybe I should add that possibility in. \$\endgroup\$
    – edgerunner
    Dec 23, 2015 at 17:50

In my Traveller Round I houseruled that it works, because I couldn't find matching rules either.

We have ruled that if you want to be able to use it, it takes up 2x its tonnage in floor spaces.

If you cram it full / stack stuff on top of it then only 1x, with the argumentation that the ship is not in crates and not rectangular itself. It doesn't use its space up efficiently, so it uses more then cargo of the same tonnage.


I found in my German Traveller book the ship "Korsar" which is designed to hold other spacecraft (for pludering). The rules there state that the Korsar can open its freight doors to allow landing of 100ton spacecraft.

The Korsar has 160tons of cargo capacity.

So, for ships optimized for the task, 1:1.6 seems to be the conversion ratio.

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    \$\begingroup\$ I was thinking something similar, ready to use x2 tons in cargo, compressed in "storage mode" x1 tons in cargo. \$\endgroup\$ Nov 27, 2015 at 11:27

As others have noted, a 'ship's vehicle' takes up only its own tonnage, with no addition for docking bays etc. This may be a game simplification but it is likely to be a deliberate design decision: the floating sort of ship, whether mediaeval or modern, has a cargo capacity expressed in tons rather than cubic feet precisely because the weight is much more important than the space taken up*. So if a fighter weighs 10 tons, the ship can haul 10 tons less of other cargo; the bottleneck is mass, not space.

*There are two exceptions: if you are carrying something notably lightweight like polystyrene (not applicable here) or if the weight is sufficiently concentrated to be in danger of going through the deck (in which case the cargo itself takes up less space than average, by definition, but the necessary spacers and strengthening beams may cause problems). The DM would need to make a successful Engineering roll to be certain whether this last applies, but bear in mind that 'normal cargo' may include bulk steel or other metals; it seems unlikely that a hollow machine, where the designer has minimised weight to improve performance, would be heavier than that.

  • 3
    \$\begingroup\$ In the Traveller editions I'm familiar with, cargo space is allocated by volume even though it's called a "ton" -- a "standard ton" in Vilani designs is 13.5 cubic meters, about the volume of a tonne of liquid hydrogen fusion fuel. All the standard vehicles were designed with this definition of tonnage, and the deck square on standard plans represented half a standard ton (by being twice as tall as its 1.5 meter length and width). \$\endgroup\$
    – Zeiss Ikon
    Dec 23, 2015 at 19:06

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