Traveller Distinctives: Jump and Its Consequences

Book 2 of Traveller (1977) states the following about faster-than-light travel:

Interstellar distance is calculated on the basis of jumps, which range in size from one to six. Some worlds are inaccessible with the use of lesser size jumps, while, in other areas of the universe, large clusters of worlds are all situated within one jump of each other. Different ships are also equipped with jump drives of different capabilities, which determine the jump distance each ship is capable of. Actually making a jump takes about one week of elapsed time, which includes navigational and pilot support, and normal preparation as necessary. Transit time to a point at least 100 planetary diameters out adds a total of approximately 20 hours to the whole trip. 

There are several things to unpack here, all of which are, I think, important to understanding Traveller and its unique style of science fiction gaming. First, there's the statement that "some worlds are inaccessible with the use of lesser size jumps." Traveller's default style of play, as its title suggests, involves traveling from world to world in search of adventure and profit. It's basically an interstellar hexcrawl – literally, given what Traveller star maps look like. However, the limitations of jump drive can aid the referee in naturalistically constraining player choice to a handful of worlds "all situated within one jump of each other," if the characters don't have access to a ship whose jump drive is capable of larger jumps. This is, in fact, a plot point in the early part of The Traveller Adventure.

This might not seem like a big deal, but I think it is. A common complaint about hexcrawl-centric campaigns is that they give players so much freedom that it's difficult for the referee to plan in advance. For inexperienced referees or even those simply uncomfortable with thinking on their feet, this can pose a problem. Traveller's jump drive system gives the referee the means to limit choice without taking it away entirely. Likewise, it does so in a way that's consonant with underpinnings of the setting rather than simply being arbitrary. 

Second, there's this: "making a jump takes about one week of elapsed time." This is regardless of the jump drive's rating. Whether your ship has a jump-1 drive or a jump-6 drive, it takes approximately one week of time (168 hours) to travel. During the time a starship is traveling, it exists outside normal space and is incommunicado. This is an important aspect of the play of the Traveller wargame, Fifth Frontier War, because the rival space navies of the Imperium and the Zhodani, once they enter jump, are committed to their final destinations and cannot change course in response to new information that might arise as a result of, for instance, battles. 

This is probably the single most important consequence of the way jump works in Traveller: the bottleneck on information. There is no such thing as FTL communication in Traveller independent of starships. Unlike many popular science fiction series, like Star Trek or Star Wars, both of which feature faster-than-light communication systems, Traveller limits communication to the speed of the fastest ship (six hexes/parsecs per week). Depending on astrography, that speed might even be less than that, as even a jump-6 ship cannot travel more hexes than are possible on the map. So, if, for example, there's not a world within six hexes of the starting world, the ship will generally travel less. (The matter gets muddled in later Traveller materials, once fuel tanks become commonplace and jumping into an open hex a possibility.)

The end result of this is that Traveller postulates a universe not unlike that of the Age of Sail, where news travels slowly and ships, even military ones, are frequently out of contact with their headquarters. The captain of a starship on the frontier can't radio back to his superiors to advise him on the best course of action. Instead, he's left to his own judgment, which is both a blessing and a curse. It is, however, great fodder for adventure. James T. Kirk was rarely in situations where he couldn't contact Starfleet for instructions, but the average Traveller naval commander has no choice but to figure things out for himself. 

Like a lot of the distinctive aspects of Traveller, it's easy to underestimate its impact. The comparative slowness of jump travel, combined with the veil of ignorance it creates for those traveling through jump space, is ripe with possibilities for creating fun and challenging scenarios. It's something that I've internalized over the years, to the point that, when I was designing Thousand Suns, I never considered the inclusion of FTL communications independent of starship travel. In fact, I listed it as one of the pillars of the game's meta-setting in my chapter on game mastering. (I also made FTL travel potentially even slower than in Traveller, but that's perhaps a topic for another post.)