- For the propulsion counterparts in the Re-imagined Series, see Propulsion in the Re-imagined Series.
In the Original Series, the Fleet moved only at sublight speeds.
Lightspeed is the term for a Colonial battlestar accelerating to the speed of light or faster. No other ship in Galactica's rag-tag Fleet had lightspeed ability, so normally the battlestar moved no faster than the slowest ship in the Fleet during its exodus from the destroyed Twelve Colonies.
Commander Cain brings Pegasus to lightspeed in order to outflank Baltar's attack force, though Cain earlier commented that such a maneuver would result in using half of Pegasus's fuel (The Living Legend, Part I).
Commander Adama orders Colonel Tigh to take Galactica to lightspeed, despite Tigh's objections that suggest that it had been some time since the battlestar was ordered to accelerate that fast (Experiment in Terra).
Note
Unlike its Re-imagined counterpart, however, Galactica apparently accelerated to lightspeed through its engines and did not perform any hyperdimensional movement.
While the Re-imagined Series attempts to ground its technology to plausible theories regarding apparent FTL travel, the Original Series was less scientific. The mechanism and theory of lightspeed travel in the Original Series was never explained.