I think the perceived output from stationary lasers on Earth would appear to decrease as your speed increases, since you're accelerating away from the laser pho

I think the perceived output from stationary lasers on Earth would appear to decrease as your speed increases, since you're accelerating away from the laser photon packets. Because of that behavior, I'm not sure it's a feasible way to get up to relativistic speed? I think the lasers would also need ~10,000 years of fuel, as opposed to ~10 years of fuel if you could somehow figure out how to carry it. But the energy to sustain in either case is probably measured in Dyson spheres, or some fraction of all energy in the universe pretty quickly too.