For POD, Laser-ranging Precise Orbit Determination System (LPODS) and satellite laser ranging (SLR) observations of the CHAMP satellite are used.
The robot also has a laser ranging scanner that acts as a "virtual" bumper.
The discoveries made by laser ranging include not only the large Love numbers but surprising perturbations in the Moon's orbit.
Laser ranging, Dr. Murphy wrote recently with eight colleagues, "is poised to take a dramatic step forward".
"We have a radar," said Dr. Jerry R. Wiant, an engineer who has done lunar laser ranging at the McDonald Observatory for 32 years.
Within the inner solar system, some distances can now be better determined through the timing of radar reflections or, in the case of the Moon, through laser ranging.
The suspicion that a sizable zone of molten rock lies hidden beneath the craggy lunar surface comes from laser ranging experiments that have increased steadily in accuracy since Apollo astronauts first put laser reflectors on the Moon in 1969.
In less than a month, Levandowski and engineers had built the Pribot – a self-driving Toyota Prius with one of the first spinning lidar laser ranging units, and the first ever to drive on public roads.
Such experiments with the reflectors on the Moon, he said, would give new life to the field of gravitational physics and provide decades of new challenges for laser ranging.
If a big laser and new detectors are added, the large telescope will be able to do laser ranging measurements in full daylight and in the light of the full Moon.
