Part of the Grand Unified FTL series.
Previously …
We discussed why Faster Than Light travel is impossible in reality, and broke down the various FTL mechanisms in fiction into five categories.
And Now …
Before we talk about travel between the stars, we have to know where the stars are located relative to each other, and how easy (or hard) we’ll have to work to get there.
Why Do We Need This?
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For the GM: At some point someone will want to know how long the trip between Horvath and Simonds World takes. It’s hard to give a definitive answer if you don’t know where Horvath and Simonds World are, relative to each other or to some reference point.
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For the Player: It’s easier to take a look at a map to decide where to go next than to pepper the GM with questions about what’s around.
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For the map maker: You get to make a map!
Star Graphs
By “graph” we don’t mean an x,y plot; that’s next section. This type of graph is, to quote Wikipedia, “a set of vertices connected by edges”, or for us laymen circles connected by lines. Each circle is a star; each line is a route between two stars. If no line exists, no direct route exists, either because there’s a closer star or because the technology, usually jump drives or portals, can’t travel that far through empty space.
On the one hand, this is the simplest star chart to draw, especially if one has only a few (three to eight) stars to draw. On the other hand, the number of possible connections grows as the square of the number of stars.
Examples of Star Graphs include the clusters of Diaspora and the portals between stars in Coriolis.
Star Maps
The next simplest sort of map to draw is a two-dimensional (or sometimes three-dimensional) plot of the distance between stars. Traveller pioneered a simple two-dimensional plot on a hex grid, something like this:
The Space Opera RPG used ordinary graph paper, but recorded the Z coordinate
next to each point representing a star. Thus one would have to compute the
distance to a star using the formula sqrt(x*x + y*y + z*z) … which is a
bit more complicated than counting hexes (or squares).
Star Tables
If one has the time and patience, one can even assemble a table of stars, almost like a train schedule, something like this:
| Alpha | Beta | Gamma | Delta | Epsilon | Zeta | Eta | Theta | |
|---|---|---|---|---|---|---|---|---|
| Alpha | - | |||||||
| Beta | 4 | - | ||||||
| Gamma | 4 | 5 | - | |||||
| Delta | 1 | 5 | 5 | - | ||||
| Epsilon | 2 | 4 | 4 | 6 | - | |||
| Zeta | 2 | 4 | 3 | 3 | 1 | - | ||
| Eta | 4 | 1 | 6 | 4 | 4 | 3 | - | |
| Theta | 1 | 6 | 4 | 5 | 6 | 6 | 1 | - |
I know of no RPG that does this, but it may be your only option if the distances (in days travel, parsecs, whatever) are non-linear.
Next
We consider the five types of FTL: