Could a "pure-electric" laser-propelled space rocket be mere decades away? I know that there probably isn't a battery capable of making this practical yet, but if it were possible to store energy at a high enough density, wouldn't that make it theoretically possible to make a rocket that uses lasers powered by on-board batteries to accelerate a spaceship? I think in 20 or so years it's plausible that technology might get advanced enough for that. Has this idea been entertained much, or are solar-sails seen as more practical? How dense would the energy storage have to be? I would assume that energy per mass densities much higher than chemical rockets would be necessary (unless if in the future this system means that there is a vast decrease of complexity of other systems involved in the regulation of the power plant). I think that ultimately it may prove superior. Imagine a spaceship that you could recharge with chemical-free refueling. The "light-fuel" could be transported at the speed of light, which you could not say for the fuel of a fusion rocket or an anti-matter rocket. "Light-fuel" could even come in any color you wanted.