Alternate rules for space travel in Fading Suns, and commentary on techniques and tactics which result from Fading Suns space travel rules.
This is a two-part message. In part one, I will discuss some proposed alternate rules for space travel in Fading Suns. In part two, I will comment on space travel in the Known Worlds, and some logical practices and tactics which might be common in the Known Worlds.
(My apologies ahead of time to those of you for whom this may seem pedantic, but you’d be surprised how many people don’t know some of the basic physics involved, or who "know" it, but don’t think about it ).
Why are alternate rules for space travel and spacecraft profiles needed?
Spacecraft as currently defined by Fading Suns are fine if all your characters ever do is simply "book passage" and travel between worlds. But if your players want more detail in order to play a Charioteer character, or a Barbarian Raider, or if you want to add some detail and "realism" to your descriptions of space travel, then the rules as they currently read are somewhat lacking.
First, the characteristics for spacecraft do not make sense mathematically or scientifically. Spacecraft are not just big cars that drive through space. However, Forbidden Lore: Technology (hereafter referred to as FL:T) defines their capabilities little differently than they do a landcraft or beast cart – by listing a speed and a range of travel.
The descriptions of spacecraft do add a secondary comment on speed that notes the number of days to a jumpgate. These numbers are incorrect according to any configuration of acceleration, speed and distance to jumpgates that I tried. Frankly, I suspect the game developers simply made them up and wrote down something that "sounded right." If I’m wrong, I’ll be happy to take that back.
More significantly, the listed stats for spacecraft provide little of direct use to a character or gamemaster who is trying to put detail into space travel. Spacecraft should be rated not according to speed, but rather the maximum acceleration of which they are capable.
Range shouldn’t be listed as a function of distance, but rather one of time – how long the spacecraft can maintain that acceleration. Listing a distance might seem intuitively correct to some, but it isn’t useful except as a general guide. A spacecraft, unlike a landcraft, can coast once it achieves a certain velocity. It isn’t necessary to continue to "push on the gas pedal" to keep going.
If you know the maximum acceleration of a spacecraft, and how long it can maintain that amount of acceleration before it has to refuel, you can figure anything else out that you need to.
If you have only what Holistic lists for the spacecraft in Fading Suns, you are lacking crucial details if you want to do anything creative with a spaceship, or if you are looking for a more "realistic" approach to running space travel adventures.
The following changes will provide a realistic level of detail to space travel, without altering the feel of Fading Suns or requiring a lot of heavy calculation. The changes I propose keep a degree of simplicity and "playability" while adding some detail to the rules for spacecraft.
First, add one additional characteristic to all FS spacecraft: acceleration. I have based the recommended ratings on an analysis of various "facts" given in the FS rules, and I will explain how I arrived at these values later in this text, for those who are interested. Those who don’t care about the math can simply use these values without worrying about the details. These stats change very little in the spacecraft listings – you just have to add them on. The only real change is in the time it takes spacecraft to reach the average jumpgate – and those changes are necessary because the times listed in FL:T simply aren’t possible (more on that later).
I have listed below what the acceleration rating for each ship should be based on the speed listed for that ship. Acceleration is given in hours per % lightspeed - i.e. it takes the ship so many hours to increase its velocity by 1% of lightspeed (1% of lightspeed is 3,000 km/second). A ship with an acceleration of 1 hour/ % lightspeed, for example, starting from a "stationary" position in space, would be traveling at 3,000 km/second after 1 hour of acceleration. (This is really fast, by the way, and much faster than even the fastest spacecraft in the Known Worlds.)
A ship with a listed "speed" of 10% lightspeed should have an acceleration of 27.8 hours/ %lightspeed, and would take a total of 278 hours to reach 10% lightspeed (or, about 12 days). Which, incidentally, is the length of time it actually would take that ship to reach a jumpgate (not 8 days as listed in the book – see below for why that is). Other ratings follow:
15% lightspeed – 12.3 hours/ %lightspeed
20% lightspeed – 6.9 hours/ %lightspeed
25% lightspeed – 4.4 hours/ %lightspeed
30% lightspeed – 3.1 hours/ %lightspeed
For range, especially for jump-capable ships where range is listed in terms of the number of jumps that can be made, no change is absolutely necessary. If you want to add some detail, however, the range can be replaced with a characteristic that lists the length of time the ship can accelerate at maximum acceleration. This can be easily calculated by multiplying the number of days it takes a ship to reach jumpgate by the number of jumps it can make, times 2.
This number will give the number of days of full accleration. Multiplying by 24 to get the number of hours of full accleration might be even more useful. That way, a pilot character will know how many hours she can afford to use up on side-jaunts, maneuvering, and can even save some fuel by coasting at a slower speed than the "maximum" listed (if she has the time to spare, that is).
Actual travel times to jumpgate for ships with various maximum "speeds" are shown below:
5% - 23 days
10% - 12 days
15% - 8 days
20% - 6 days
25% - 5 days
30% - 4 days
These times assume constant acceleration and are mandated by physics, based upon the stated distances from planets to jumpgates (see below for a full explanation). The times stated in the books simply are not consistent with the stated distances to jumpgates and the maximum speeds listed for various ships.
Several assumptions had to be made to determine usable values for space travel. Foremost among these is the assumption that physics works the same way in the Fading Suns universe as it does in ours – not a big stretch, but little things like what the speed of light actually is rely on such an assumption. There are a couple of others that aren’t quite as obvious:
With these assumptions in mind, the maximum acceleration a ship is capable of maintaining can be calculated. The distance is known, and the final velocity is known. Since constant acceleration is assumed, the average velocity is also known (it will be half of the maximum speed for that ship – a ship with a "maximum" speed of 10% lightspeed would average 5% lightspeed over the entire journey). Because the average velocity is known, the travel time is also known, and when that is figured into the values for final speed and distance, acceleration results. So, with constant acceleration assumed, the acceleration ratings for the various ships can be easily calculated, and the resulting values added to spacecraft profiles.
The average speed derived from the listed "maximum" speed also mandates the minimum travel times to a jumpgate. If a ship can travel no faster than 10% of lightspeed, for example, it cannot start (stationary) at a planet and arrive at a location 15 billion kilometers away any sooner than 12 days later. It just isn’t possible unless the laws of inertia are somehow ignored (see assumption 3 above). The other revised times to jumpgate are based on this kind of simple calculation (take half the speed listed, multiply by 300,000 km/sec, and do the math based on minutes, hours, and the 15 billion km/100 AU distance).
As a side note, 1 Astronomical Unit (AU) is equal to roughly 500 light-seconds. Put another way, it takes light about 8 ½ minutes to reach the earth from the sun. A ship traveling at 10% of lightspeed would take 83 minutes to travel the same distance. A ship which started at the sun and accelerated constantly toward the earth at a rate which would cause it to hit 20% of lightspeed just as it reached the earth would also take 83 minutes to make that trip (it’s average speed over that distance would be 10% of lightspeed).