LRO LOLA Radiometric Data Record (RADR)

RADR – Radiometric Data Record

Instrument: Lunar Orbiter Laser Altimeter


For more information about LOLA RADR products, see the RADR Data Set Description.

For more information about all LOLA products, see the LOLA Archive Volume SIS.

The Lunar Orbiter Laser Altimeter (LOLA) Radiometric Data Record (RADR) data products are presented as along-track profiles that contain normal albedo, the radiance of the Moon at zero phase angle relative to a Lambert surface illuminated normally. Normal albedo has been corrected for the sensitivity drift of the laser with time, and for the loss of signal from temperature-dependent loss of alignment of the laser transmitter in the polar regions. Calculations are done as described in Lemelin et al. 2016 (doi:10.1016/j.icarus.2016.02.006) using laser data collected during the thirteen Nominal Mission phases.

RADR files are archived as ASCII tables with detached labels. Each table file contains data for a given LRO orbit, where each line corresponds to a laser return. The data is stored in 13 columns: latitude (degrees), longitude (degrees), normal albedo, Terrestrial Dynamic Time, laser used, detector used, reflectance (fraction), received energy (zJ), transmit energy (mJ), range (km), solar incidence angle (degrees), off-nadir angle (degrees), dropoff fit (fraction).

RADR products are derived from nominal mission data only, and are further limited – not every return with valid altimetry has a corresponding albedo value, as the energy measurement quality depends on both the laser return and the solar incidence angle. Low data density results in some ‘streakiness’ seen in the gridded albedo products.

The following conditions were applied to qualify pulses for inclusion in a data file: solar incidence angle lower than 90 degrees (daytime data), received energy greater than 0.14 zJ, a spacecraft off-nadir angle between 0.2 and 0.4 degrees, and an overall range lower than 70 km from the surface.

Data products with an “_NP”- or “_SP”-suffixed file name contain normal albedo data acquired by Laser 1 at solar incidence angles greater than 90 degrees (nighttime data), which have been used to fill the gaps in coverage near the poles that occur when using daytime data only. For the south polar region, nighttime data from orbits 4014-4264 were included between 85-90 degrees South. For the north polar region, nighttime data from orbits 4850-4971 and orbits 5318-5360 were included, between 87-90 degrees North. The nighttime normal albedo data have been scaled to the daytime normal albedo from Laser 1 in overlapping regions.

LOLA RADR non-polar products have the following file names:

LOLARADR_yydddhhmm.TAB (with detached PDS label)


yydddhhmm = UTC start time of observations, rounded to the minute

LOLA RADR polar products have the following file names:

LOLARADR_yydddhhmm_pp.TAB (with detached PDS label)


yydddhhmm = UTC start time of observations, rounded to the minute

pp = polar suffix

NP = north polar

SP = south polar

In ODE, RADR products have the following product IDs: