The Lunar Orbiter Laser Altimeter (LOLA) will provide a precise global lunar topographic model and geodetic grid that will serve as the foundation of essential lunar understanding. This will aid future missions by providing topographical data for safe landings and enhance exploration-driven mobility on the Moon. LOLA will also contribute to decisions as to where to explore by looking at the evolution of the surface.
LOLA fully achieves three LRO measurement objectives and addresses two other. LOLA will provide all the data necessary to select intriguing, safe landing sites, while providing the reference system needed to navigate to those sites.
LOLA builds on extensive spaceflight heritage, including the Mercury Laser Altimeter (MLA) and the Mars Orbiter Laser Altimeter (MOLA). The LOLA measurement team has 15 years of altimetry experience that includes providing MOLA data to the Mars Exploration Rover site-selection teams.
Image Above : LOLA Engineering Model
LOLA produces improved lunar gravity models , as well as global, regional, and local (meter-scale) models of:
- Geodetic Topography
- Surface slopes
- Surface roughness
- Surface brightness
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.