
Whatever Happened to Photon Rockets? (2013) - dmmalam
http://www.armaghplanet.com/blog/whatever-happened-to-photon-rockets.html
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Animats
Because, physics.

Laser launch has some of the same problems. It takes about a megawatt to lift
a kilogram.

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david-given
Way more than that. The numbers for photon rockets come out at about 300 MW/N.
So to lift one kilogram against earth's gravity you need about three
gigawatts.

This is why people generally prefer to use the energy to accelerate reaction
mass instead of just generating photons.

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randallsquared
Usually "laser launch" means using a ground-based laser to heat propellant on
the rocket. These seem entirely different from photonic rockets to me, but the
wiki article on laser propulsion lists them as two examples. Confusion has
ensued. :)

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InclinedPlane
Photon rockets are only feasible if you have crap-tons of anti-matter. And
even then, only in some uses.

