If you can calculate the distance measured by the reflection of sunlight. Why place a laser pointer on the moon to calculate the distance to the earth? You misunderstood the subtle operation you did. Instead of sending laser light to the moon, we sent a laser beam. And we still do. The Apollo mission (and two Soviet landers) placed a retroreflector on the moon, which is an efficient reflector that can reflect the laser beam back to itself like a road reflector. When we fire a powerful laser pointer at one of the planets. When it reaches the moon, it will spread out more than a mile in diameter. The part hitting the reflector is scattered much more on the return journey. In the end, only a few photons reach the detector on Earth.
So why do we want to do this. Because the previous method can only help you solve the problem. Various astronomical observations have been used to measure the distance to the moon. By the time of Jules Verne, we knew the average distance to within 100 kilometers. By 1962, this distance was reduced to 2 kilometers, close enough to use radar to put the spacecraft into orbit and land. Therefore, we do not need laser ranging to reach the moon-we are already there. We have placed reflectors for science. By sending a laser pointer beam and accurately measuring the round-trip time of light in many experiments. We can measure 100,000 times more accurately. Now we know that the moon retreats by 3.5 centimeters every year.