P.S.L.

Percent Speed of Light.

A commonly-used measurement of star ship velocity. However, most ships are not rated by their top speed(generally no higher than around 70 P.S.L.) but by how fast they can reach it. This is known as the Acceleration curve. A ship with a high "curve" will have a higher rating. Rating is still listed in PSL(for example: the Harpy long-range bomber is "rated" 70 PSL+) but describes how fast it can reach that speed, not it's top speed.

Different groups measure velocity in different ways. In the case of the Gudersnipe Foundation, a graph is used based on engine output, delta-V, and various other factors. A ship placed at any point on the graph will reach it's maximum rated speed before the end of the graph. If a vessel is always capable of reaching 70 PSL within these parameters, it is given the rating pf 70 PSL+.

Because this rating is not tied to ship-size, what a rating means can have very heavily from ship to ship. For example, the Harpy bomber and Sahar Jusenkyou-Class Carrier are both rated as 70 PSL+. The bomber takes roughly fifteen minutes to reach 70 PSL(10 under War Emergency Power, depending on it's launch speed. The Sahar, meanwhile, requires over an hour. However, most of the Sahar's acceleration curve is given over to bringing the engines up to full power. Once at maximum output, they can apply considerably more delta-V than most ships that size. Hence the high rating.