Hi Harlan, I refer you to the original documentation describing the technology at: http://www.deepspace.ucsb.edu/wp-content/uploads/2015/04/A-Roadmap-to-Interstellar-Flight-15-d.pdf. The author proposed a small test system to start but argues it is scalable starting with power per mass at 5 kg/kw with the size of a 1 kw amplifier no bigger than a textbook. He goes on to state the “laser system can be built and tested at any level from desktop to extremely larger platforms.This is radically different than the older “use a huge laser” approach to photon propulsion.This is the equivalent to modern parallel processing vs an older single supercomputer.”

I do not have time to do any calculations but almost certainly the beam density would “fall off” so steeply that a very simple demo is all that could be done. For a real demo you would need a high powered laser. From where would you fire even a single full power laser beam?

If you figure the cost of putting a powerful laser on the only possible place – a mountain top – it would cost a billion dollars. First every tattooed demonstrator would block construction. Then you would have to extend high voltage power lines. Then you could start on building a facility that would rival the Thirty Meter Telescope in cost and complexity.

So you could demo the system with the existing low power lasers but it would be very costly to scale it up.

Sigh.

I don’t believe Lubin’s hypothetical system would require the billions you are suggesting for a pilot project.

I cannot imagine that a laser could still accelerate a spacecraft which was even 1/2 way to Mars – the density would have to be very slight by that distance.

If we could manage to find a location for the laser it might be worth a trial, but locating such a laser would be very tough. It could be on a mountain top – as long as we could spend billions getting high voltage power lines up there. It could be in space as long as we could overcome public opposition to launching a nuclear power source into space.