​Adventuring Aids: Space Travel

There are many ways of traveling interstellar space. Some methods are more useful than others. The most common (in this neck of the woods, anyway) is the use of the Gravity Drive to enter hyperspace. High speed travel is usually measured in bmph, or billions of meters per hour.

Gravity Drives: A gravity drive accelerates all mass within it’s confines at the exact same rate. This allows the ship to reach speeds close to and in excess of light speed without the ship shearing apart. It also negates the effects of acceleration inside the ship.

In order to enter hyperspace (faster than light speed), the ship must already be going at a speed equal to the Gravity Drive Type, squared, bmph. Ships should not enter hyperspace near a large mass: Look up the gravity (in multiples of Earth gravity) on the Doubles Chart, and subtract the Gravity Drive type, for the amount of damage the ship takes, directly to DP.

The Top Speed of a ship equipped with a gravity drive is the ship’s Top Speed in bmph minus Mass (Doubles) plus the Drive Type squared. This number cannot be greater than the ship’s Top Speed in bmph. This is the ship’s hyperspatial speed in light years per day. Performance Time for Maneuverability is the ship’s Mass (Doubles), squared, segments.

There are three types of gravity drives: Linear drives, Square drives, and Cubic drives. Linear drives allow maneuverability in a line: forward and reverse. In order to turn, the ship must exit hyperspatial travel and turn on normal drive. Square drives allow maneuverability in a plane, and Cubic drives allow maneuverability in any direction.

Hyperspace: Hyperspace is that restricted part of the universe where mass travels at greater than the speed of light. Any mass that travels through the light barrier is translated into hyperspace. The perception of time in hyperspace is similar to the perception of time at near light speed. The formula is as follows. C is the speed of light:

Take the square of the number of Cs the character is moving at, and divide this into 1. Subtract this from 1. Take the square root of this. Multiply normal time by this for perceived time. For example, if a character spends 20 hours traveling at twice the speed of light, the character will perceive .87 times this, or about 18 hours. Which isn’t really worth worrying about, unless the character is carrying a bomb set to go off at a certain time.

Near Light Speed: At near light speeds, it takes a long time for travel to occur, but the ship occupants don’t necessarily know this. At speeds near that of light, the occupants of the ship will see less time than those outside of the ship. If the ship is going at 90% of the speed of light, and the ship is gone for 20 years, the crew will only think 9 years have gone by. At 95% of the speed of light, 20 years would seem like 6 years. At 99% of the speed of light, 20 years would seem like less than 3 years. Here’s the formula (yuck) for determining the fraction of ‘real’ time the occupants see:

Square the fraction of the speed of light that the ship is traveling (.9 becomes .81, .95 becomes .9025, etc.) and subtract this from 1 (.81 becomes .19). Take the square root of this (.19 becomes .44). That’s the multiplier to ‘real time.’ So, 20 years of traveling seems like 8.8 years to someone traveling at 90% of the speed of light.

While characters who can travel at nearly the speed of light are assumed to be able to do so, ships will need protection, usually in the form of a gravity drive. Ships that are unprotected at such high speeds will take damage. For every one tenth of the speed of light (round down), the ship will take one point of damage per minute.

Sublight Speeds: This is the most primitive form of space travel. The ship travels at low speed, and takes hundreds, if not thousands or millions of years, to reach its destination. The crew is either placed in stasis or suspended animation, or the ship is designed to sustain generations of crewmembers.