Since NASA launched the Lunar Reconnaissance Orbiter (LRO) into the moon’s orbit in 2009, scientists have been firing lasers at a small reflector array to bounce light back to planet Earth and have finally made a breakthrough as the photons have successfully reflected back.
By leaving behind equipment for continued monitoring such as seismometers and laser reflectors, scientists are given a way to perform measurements of and around the Moon.
With the measurements, scientists can understand the conditions on the lunar surface that could be degrading instruments placed there over 50 years ago. The measurements will also help determine how the moon moves around, rotates if there is solid material in the fluid core. By this scientists also know that the Moon is moving away from the earth at a slow rate of about 3.8cm per year.
Scientists can compare the results from the surface reflectors if signals can be received bouncing off its reflector.
“If you send a really powerful laser beam at the Moon and time how long it takes to bounce back, you can make a really accurate measurement of the distance between the two points, based on the speed of light. Thus, we can determine how far away the Moon is, with millimetre precision,” Science Alert explained.
"Now that we've been collecting data for 50 years, we can see trends that we wouldn't have been able to see otherwise," planetary scientist, Erwan Mazarico of NASA's Goddard Space Flight Center said.
However, the amount of light returned from those lunar reflectors has dimmed, to as little as 10% of what it should be. The reason is not yet known.