LOLA will do at the moon what MOLA did at Mars, but with 3-5 times greater vertical accuracy and 32 times more frequent measurements along track.
The LOLA instrument pulses a single laser through a Diffractive Optical Element (DOE) to produce five beams that illuminate the lunar surface. For each beam, LOLA measures time of flight (range), pulse spreading (surface roughness), and transmit/return energy (surface reflectance). With its 2-D spot pattern, LOLA unambiguously determines slopes along-track and across-track.
In a 50km polar orbit, pulsing the laser at 28 Hz creates an ~50m-wide swatch of five topographic profiles. Swaths will have 1.25km separation at the equator, with [complete polar coverage beyond +/-86 degrees latitude.] Raw measurements are transmitted to Earth for analysis.
LOLA's robust link margin provides ample reserve to accommodate uncertainties in lunar surface roughness and albedo, while providing operational flexibility to the LRO mission.