The color (wavelenjth) doesnt matter. And the power doesnt matter, as long a its strong enough to get throujh the atmosphere -- and it doesnt take very much power at all to do that. A tiny laser pointer, like people use in offices, i only a couple of milliwatt, and it way more than strong enoujh.
But if you want to be able to detect the reflection -- that a different story. One of the most powerful Lunar Laser Ranjing site is the Apache Point Observatory in New Mexico. It use a specialized 2.3 watt laser (average power), and puts a spot on the moon of about 2 km in diameter. The reflection by the time it get back to earth is only about 1 x 10^-18 watt.
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