I’ve been developing a small ship, small universe Traveller setting that’s based on the spread of Terrans from the solar system over a couple of centuries. One of the things I wanted to do with this setting is to make habitable worlds extremely rare. Out of the 50-odd systems in my setting, there is a single planet with a breathable atmosphere aside from Earth. There are 6 other planets which are potentially terraformable, but most human habitation remains in space. This pushes my setting away from the traditional “one main world in an otherwise mostly uninhabited system” feel of standard Traveller, and I wanted to see what that might do to the feel of a system.

So, of course, I decided to dig into the economics of it, first…

Interstellar travel in Traveller requires a passenger starship, and the price of travel is based on the price of running that starship.

The Type A, for instance, has the following costs of operation:

We’ve calculated costs per fortnite (14 days), instead of per jump, though this is the same for most commercial starships. For this, it can carry 82 tons of cargo, 6+ warm passengers, and 20 low passengers, and the cargo/passages it sells have to pay this. You can imagine liner variants that carry relatively small quantities of cargo, but have up to 20 more staterooms for warm passengers, but the economics for those remains largely the same.

Adding onto this are the life support costs. That high passage doesn’t give the trader 10,000 credits in profit, because 2,000 of it go towards paying the life support fees. If you imagine about half the passages sold are medium, that’s an average of Cr 7,000 for the ship per passage. Add to that Cr 900 per low passage, and estimate Cr 900 per ton (since it’s rare that a trader fills up the whole hold), and that’s the ship’s income. For our example Type A, that’s about Cr 134,000 per jump Enough to pay for everything, with a profit for the owner.

Now let’s look at insystem travel on a nonstarship or small craft. It’s easy to assume this will fall into an entirely different category of service, but it’s not too dissimilar to interstellar travel. Taking a shuttle from Earth to Jupiter, for instance, is a 4 day trip.

So let’s look at the cost of the shuttle – 95 tons, 71 tons of free space, for MCr 33. The crew of 2 is probably pilot and engineer. To this we’ll add a medic and steward, for limited passenger service. Like the Type A, it could carry more passengers for less cargo, but we’ll try to keep it similar to the Type A:

So far the costs are pretty similar to the Type A, though I suspect a shuttle can easily manage 2 paying trips per fortnite. This allows for something like the 4 day Earth-to-Jupiter transit time, plus a few days in dock to handle cargo transfer, maintenance, and the like.

Since the Type A’s passenger pays on average Cr 7,000 + life support for their passage, and the passage takes twice as long as the shuttle’s flight, the shuttle passenger probably pays something closer to Cr 3,500 + life support for their passage. The life support is probably half as expensive, too, since the trip takes half as long, so that’s probably around Cr 4,500 total for passage on the shuttle.

This is not cheap.

One of the common conceits of Traveller is that interstellar travel is expensive. This allows for individual systems that develop their own cultures, without large scale mixing with other nearby cultures. But we can see here that insystem travel is also quite expensive, and probably contributes to a similar feel within a system. Because of the cost of travel, a habitat at Saturn would likely not see a lot of intermixing with a base on the Lunar surface.

There are all sorts of implications that come out of this. Individual habitats in a system will likely develop their own cultures, their own identities. They might see themselves in competition with the other habitats in the system. There might be tension between habitats, amplified by cultural differences and feeding distrust. It makes individual systems feel roomier, with more for players to do.