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International Archives of the Photogrammetry, Remote Sensin 
g and Spatial Information Sciences, Volume XXXIX-B4, 2012 
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia 
EXPLORING THE MOON WITH THE LUNAR RECONNAISSANCE ORBITER 
CAMERA 
Mark S. Robinson', Emerson J. Speyerer^, Aaron Boyd", Devin Waller", Robert V. Wagner, Kyle N. Burns“ 
“Arizona State University, School of Earth and Space Exploration, 1100 S Cady, Tempe AZ, 85287 — 
(robinson@asu.edu) 
Commission IV, WG IV/7 
KEY WORDS: High resolution, Planetary, Mapping, Mosaic, DEM/DTM, Imagery, Multispectral, Multitemporal 
ABSTRACT: 
The Lunar Reconnaissance Orbiter Camera (LROC) consists of three imaging systems: a Wide Angle Camera (WAC) and two 
Narrow Angle Cameras (NACs). Since entering lunar orbit in June of 2009, LROC has collected over 700,000 images. A subset of 
WAC images were reduced into a global morphologic basemap, 
sequences that characterize illumination conditions of the polar re 
maps and digital elevation models of select regions of interest. T 
through NASA's Planetary Data System to aid scientists and eng 
questions. 
1. INSTRUMENT OVERVIEW 
The Lunar Reconnaissance Orbiter Camera (LROC) system 
provides synoptic and high resolution imaging of the lunar 
surface [Robinson et al, 2010] The Wide Angle Camera 
(WAC) is a seven band (315, 360, 415, 566, 604, 643, 689nm) 
push frame imager with a 90? field of view in monochrome 
mode, and 60? field of view in multispectral mode. From the 
nominal 50 km polar orbit, the WAC acquires images with a 
nadir pixel scale of 75 meters for the visible filters (384 meters 
for the UV filters). The WAC images almost the entire Moon 
each month, capturing the lunar surface under a variety of 
lighting conditions over time. This global dataset enables the 
creation of morphologic maps, near-global digital elevation 
models (DEMs), and polar illumination movie sequences. 
The Narrow Angle Camera (NAC) consists of two line scan 
cameras that provide high resolution images at a pixel scale of 
0.5 to 2.0 meters and a combined field of view of 5.7°. Around 
summer solstice at each lunar pole, when shadows are at a 
minimum, hundreds of images are acquired and later reduced 
into high resolution maps. These NAC polar mosaics extend 
from the pole out to 85.5° N/S and have a pixel scale of two 
meters. In addition to polar mosaics, high resolution (pixel scale 
between 0.5 and 2.0 meters) maps are also created for other 
regions of interest across the Moon. Finally, NAC stereo 
observations are also processed into high resolution DEMs. 
DEMs generated from NAC stereo pairs acquired over many 
months are processed and mosaicked to create regional terrain 
models with a pixel scale of two to five meters. 
Since entering orbit in 2009, LROC has acquired over 700,000 
images WAC and NAC images. A subset of this image 
collection provides the basis for the production of DEMs and 
image mosaics over a broad range of spatial scales. LROC 
images (Experiment Data Records, or EDR) and Reduced Data 
Record (RDR) products created by the LROC team are publicly 
released through NASA’s Planetary Data System to aid 
a near-global digital elevation model, and multitemporal movie 
gions. In addition, NAC observations were reduced to meter scale 
hese Reduced Data Record (RDR) products were publicly released 
ineers in planning future lunar missions and addressing key science 
scientists and engineers investigating the Moon [Jolliff et al., 
2011, Mahanti et al., 2012; Ashley et al., 2012]. 
2. REDUCED DATA RECORDS 
2.1 WAC Global Basemap 
The WAC global mosaic is comprised of over 15,000 images 
acquired between November 2009 and February 2011. The 
WAC maps the whole Moon in one month, however the solar 
incidence angle at the equator changes about 28? during a 
month. To even out the monthly incidence angle variations, the 
equatorial mosaic is comprised of data collected over three 
separate periods (1/20/2010 to 1/28/2010, 5/30/2010 to 
6/6/2010, 7/24/2010 to 7/31/2010). The south polar mosaic 
images were acquired 8/10/10 to 9/19/10 and the north polar 
images 4/22/10 to 5/19/10 (Table 1, Figure 1). Remaining gores 
were filled with images acquired at other times with similar 
lighting conditions. The non-polar images were map projected 
onto the GLD100 (WAC derived 100m/pixel DEM) while polar 
images were map projected on the LOLA shape model (79? to 
90* N/S) and the GLD100 (60? to 79? N/S) [Smith et al, 2010; 
Scholten et al., 2012]. In addition, the LOLA derived crossover 
corrected ephemeris and a precise camera pointing model 
provide accurate positioning of each WAC image (to within a 
pixel) [Mazarico et al., 2011; Speyerer et al, 2012b]. Because 
the polar images were acquired at a different season than the 
equatorial images, and the lunar photometric function is not 
perfectly known, there is a brightness difference where the polar 
mosaics meet the equatorial mosaics. In a future release this 
discontinuity will be reduced. 
The WAC global mosaic is archived in ten regional tiles (Table 
1) at three different pixel scales to better serve the lunar science 
community: 100 meters per pixel (mpp), 256 pixels per degree 
(ppd) and 128 ppd. Eight of the tiles are equirectangular 
projections that encompass 60? latitude by 90° longitude. In 
addition, two polar stereographic projections are available for 
the poles from 60? to 90? north and south, respectively. 
469