Fig. 1. Retro-reflectors landed on the Moon by Apollo 15^[4]

Fig. 2. Positions of three Apollo retro-reflectors (A11, A14, and A15) and two Lunakhod retro-reflectors (L1 and L2) on surface of the Moon

Fig. 3. Beam offset optimization result on December 9, 2005 (at offset step of 0.25″)^[16]

Fig. 4. LLR residual data of Apollo 15^[12]

Fig. 5. Histogram of LLR residual data at certain interval^[12]

Fig. 6. Receiving echo of Apollo 15 LRRR for 8000 times launching on March 23, 2010(receiving echo within 12 ns interval for 100 ns gating)^[21]

Fig. 7. Sequence distributions of APOLLO lunar laser ranging data on March 23, 2010. (a) Reference signal reflected by calibration angular reflector on telescope; (b) reflection signal of LRRR on Apollo 15

Fig. 8. APOLLO lunar ranging results under different phases of the Moon and numbers of experiments and failures of Apollo 15 lunar ranging. (a) Distribution of number of experiments and number of failures of Apollo 15 lunar ranging (from October 3, 2006 to June 15, 2009)^[25]; (b) APOLLO lunar ranging results under different phases of the Moon^[26]

Table 1. Earliest LLR data measured by Lick observatory^[2]