Ground-based laser propulsion methods

[Phronesis]

Hi all – How far have we gotten with ground-based laser propulsion technologies? I'm thinking mostly about pulsed plasma propulsion where air is the working fluid for an SSTO launch.

There are snippets of information at Wikipedia for laser propulsion: https://en.wikipedia.org/wiki/Laser_propulsion#Laser_energized_rocket

And the remarkable Lightcraft: https://en.wikipedia.org/wiki/Lightcraft

Separately, I think I've read about small-scale tests that launched a few pounds up to some low altitude.

How viable do you think the core concept is? We can combust air under an appropriately designed launch vehicle. Is it the power of the lasers that is the constraint right now?

[Damon Hill]

I'd think a high and very dry desert location might be an ideal location for laser launch.

The main limitation would be a laser system that could operate at megawatt levels for at least several minutes, probably a modular system that would be easier to scale up and tolerate partial failures.

[speedevil]

The main limitation would be a laser system that could operate at megawatt levels for at least several minutes, probably a modular system that would be easier to scale up and tolerate partial failures.

A megawatt looks like a lot of power for a LASER.
'A hundred grams of RP1/LOX equivalent power' is a lot less impressive.

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.522.2954&rep=rep1&type=pdf - is an example of a SSTO using microwaves, not LASERs, to heat hydrogen in a heat exchanger.

This is 250MW, with payload of 100kg, and 1 ton wet mass.