[Laser] Lunar Laser EDM

[Patrick Barthelow]

Hi Everybody,


Does anyone know how big the laser spot size on the moon is, that they send via an Arizona telescope to the moon to measure distance using the 
retroprism arrays left by the Apollo missions?   The can resolve distance apparently to near mm levels.

The Apollo era  retrprism arrays are on the order of a meter or two, rectangular, and have a lot of I think, 1" to 2.5 " crystal retroprisms.   The Arizona station only 
receives 10s of photons per second on the return.    If you only had a single 2.5" retroprism on the moon, would that severely limit return signal compared to an array 
of say of 100 prisms?

Best Regards,   
Pat Barthelow; Echoes of Apollo
 apolloeme at gmail.com   apolloeme at live.com