Firstly, I must agree with Robert B that you'll need an awfully powerful laser. However, if you were to adapt my strategy of measuring the angle of lead for a hit on the LRRR, I don't see why this is not feasible. [Robert Bennett] This is not feasible/practical, as reading the description of the LLR by NASA indicates. First, the lead angle is ridiculously low, as Paul shows below. More importantly, the beam can't be aimed to the precision required. So NASA sweeps the laser beam across the general area of the reflector, detecting a hit by the return echo. The divergence of the outbound beam to 2 KM benefits this method, since it amplifies the area of search (at the price of greatly reduced intensity). Advise reading the NASA description, to save extended speculation. RB Of course you would need to conduct the experiment at full moon or new moon rather than half moon to maximise the effect. But you have only a 3 km/s +/- 1 km/s difference -- not a lot to play with. The difference in angle of lead is then a minimum of 298 u deg and a maximum of 596 u deg. This is less than A. Centauri's parallax. Paul D