It's like asking, "I'm stuck in Bangkok with $50, why can't I just pay a passing rickshaw to take me back to New York?"

Or, "Why can't Elon Musk just fly the Falcon 9 rocket to Alpha Centauri?"

RimWorld depicts space travel realistically. Moving across a planet is very different from traveling to a moon, which is very different from traveling to another planet, which is many many leagues below traveling to another star.

Consider: You're aware that there are people in Earth orbit now. You know a few people went to the moon once, but it's far harder than just going to orbit. You know there is talk of some day going to Mars, but it's much harder than the moon and nobody's ever done it (it takes months to get to Mars, where the moon takes 3 days). Going to Uranus would be way, way harder than going to Mars (years instead of months). And going to another star is just unimaginably harder on every level (thousands of years at current technology).

In the game, nobody in the rimworld system has a ship that can go further than perhaps a local moon (except the Empire, and they won't take you unless you climb the ranks). They won't take you to another star, because they can't get to another star either.

The problem here is that people are miseducated to think of space travel through Star Wars and Star Trek, where the difference between "traveling across the planet" and "going to another star" is completely ignored. In reality it's like asking why a garden slug can't climb Mount Everest.

Papergeist

Does this mean that trade ships don't travel between planets?

I ask because I'm not sure how that would work, and had generally assumed trade ships did indeed make the long hauls to other systems, while the Rim system was a nameless rock along the way to a real destination.

It seems pretty cool, but I've got a ton of questions about it too. Where do trade ships come from, do they have bases planetside, how do they maintain themselves, are they even manned at all, and why is it they can't assemble the means to make a long-haul trip to barter their way to a better world with space oddities.

I'm prone to making up lore, but if we've got more somewhere, I'd like to devour it.

The game doesn't nail down the details of the trade ships, but if you read the universe backstory you can infer that at the minimum they are not interstellar ships. They could be intraplanetary, cislunar, or interplanetary, it's not really specified.

-desdinova-

My issue with this is that since a reactionless drive exists, there's no reason you can't accelerate to any arbitrary fraction of light speed. At a constant 1g acceleration it takes a little less than a year to accelerate to 99% of light speed. Because of relativistic time dilation, if you're going fast enough, the time elapsed during a journey perceived by the crew could be many times less than the time perceived by a stationary observer. Basically, any ship equipped with a Johnson-Tanaka drive is a potential starship.

Once you accelerate to 99.9% c, a journey of 10 light years would take less than 6 months from your perspective - just add a year to speed up and a year to slow down. You wouldn't even need cryptosleep caskets for many interstellar journeys.

It depends on the assumptions of course, but as I have the universe written:

Trade ships don't have JT drives.

JT drives don't give 1g.

Trade ships don't have foreshields to block lightspeed dust impacts (which you need to not have your ship annihilated if you go fast enough for time dilation to be really serious).

10 light years is very close, a more typical journey would be more like 50-100 ly (to get to a system with anything interesting in it).

And even in your hyper-optimistic scenario you're describing a 30-month journey. Without cryptosleep you need a ton of food, a ton of redundant life support, a ton of space to not go crazy being in a tin can for 2.5 years (all heavily rad-shielded), and lots of other things neither of us are even thinking of.

In any case, this is all way, way outside the scope of "give them some dog leather and ask to hitch a ride" from the OP.