Propulsion (TOS)

For the propulsion counterparts in the Re-imagined Series, see Propulsion in the Re-imagined Series.

In the Original Series, the Fleet moves seemingly only at sublight speeds. There are inferences to FTL use though, even if sporadic and uncertain.

Lightspeed is the term for a Colonial battlestar accelerating to the speed of light or faster. Galactica is one of the few ships in the rag-tag Fleet that have lightspeed ability, so normally the battlestar moves no faster than the slowest ship in the Fleet during its exodus from the destroyed Twelve Colonies (Lost Planet of the Gods, Part I).

It is rarely mentioned, but beyond the following references, FTL is inferred several times in the original Battlestar Galatica. Even just the mention of leaving star systems (possibly mentioned inaccurately as 'galaxies') and showing up in other star systems within short periods of time, lead one to suspect that some form of superluminal propulsion is employed.

• 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).

• Baltar and Lucifer have a conversation in which Lucifer states that the Cylons could easily catch up to the slowly moving rag-tag Fleet if they used lightspeed (Lost Planet of the Gods, Part I).

• Starbuck's Viper "Recon 1" could be inferred to be able attain this lightspeed as well, as it has to drop to sub-light when it detects a freighter and fighter (The Long Patrol).

Other than these oblique references, there is nothing that would substantiate how the ships achieve this form of propulsion other than by just accelerating until they reach their top speed.

Notes

• While the Re-imagined Series attempts to ground its technology to plausible theories regarding apparent FTL travel, the Original Series is less scientific. The mechanism and theory of lightspeed travel in the Original Series is never explained.

• Given that the Fleet and Vipers regularly visit other star systems and even a few references to flying to other galaxies, it's scientifically implausible that the Fleet only moves at sublight speeds. Even at a large fraction of the speed of light, traveling from one star system to another would take years or even decades. Flying to another galaxy is impossible within a human lifetime without severe time dilation due to relativity. Even the nearest galaxies are several hundred thousand light-years distant from the Milky Way.

• From what can be gathered, the FTL technology employed appears to somehow negate the ever increasing mass due to reaching relativistic speeds, at least partially. This could then be related to somehow negating the mass of the ship or by at least keeping it constant. The Galactica's Light Speed ability may be a very fast ability to reach the superluminal top speeds at the cost of fuel effeciency. With that supposition and earlier ones, the Fleet may be able to go beyond the speed of light, but it may take them days at a very slow acceleration. Without the constraint of Relativity, even just one gravity of acceleration would be able to overcome light speed in not too long of time.