Esta é Crusade , um spin-off de curta duração da Babylon 5.
Da Wikipedia:
Excalibur features energy and particle beam weapons. The main guns operate at two main power levels. "Level One" provides beams with little more firepower than a White Star. "Level Two" is much more powerful weapon, reverse engineered from Vorlon lightning cannon technology. [...] Firing this titanic weapon drains all the ship's power and the "Excalibur" is unable to maneuver, fire weapons or use long-range scanners for approximately one minute afterward.