Fig. 7From: First two-way laser ranging to a lunar orbiter: infrared observations from the Grasse station to LRO’s retro-reflector arrayEvolution of key geometry parameters. These are shown for the LRO-Grasse opportunities, between January 1, 2018 and September 22, 2019. The black lines give the complete time series of these parameters, and the blue lines the segments where the constraint on that parameter is satisfied. Their total duration relative to the time span is given in parenthesis as a percentage. The red lines indicate the periods where all four constraints are satisfied and thus when passive ranging may be attemptedBack to article page