Dirt cheap. Laser with galvo (like many laser projectors for light shows have), plus 3 photodiode detectors and optics. Most of the cost will be in the telesc

Dirt cheap. Laser with galvo (like many laser projectors for light shows have), plus 3 photodiode detectors and optics. Most of the cost will be in the telescopes. If you don't count personnel time integrating/fiddling around, maybe $1000 at qty 1?