GOALS AND OBJECTIVES: IMPACT CRATER SIZE FREQUENCY STATISTICS ENABLES THE ESTIMATION OF RELATIVE AND ABSOLUTE MODEL AGES OF UNSAMPLED UNITS ON THE MOON AND OTHER SOLAR SYSTEM OBJECTS [1 2]. ONE TECHNIQUE USED TO EXAMINE THE CURRENT IMPACT RATE IS TO LOOK FOR SURFACE CHANGES IN A BEFORE AND AFTER IMAGE WITH SIMILAR LIGHTING OFTEN REFERRED TO AS A TEMPORAL IMAGE PAIR. RECENTLY ANALYSIS OF TEMPORAL IMAGES ACQUIRED WITH THE LUNAR RECONNAISSANCE ORBITER (LRO) NARROW ANGLE CAMERA (NAC) AND WIDE ANGLE CAMERA (WAC) [3] HAS REVEALED HUNDREDS OF NEWLY FORMED IMPACT CRATERS AND THOUSANDS OF OTHER SURFACE CHANGES [4 5]. ONE LIMITATION TO THIS TECHNIQUE IS THE REQUIREMENT THAT TWO IMAGES MUST COVER THE SAME SURFACE AREA UNDER SIMILAR ILLUMINATION CONDITIONS. BY LEVERAGING IMAGES FROM MULTIPLE MISSIONS WE CAN INCREASE THE NUMBER OF IMAGES THAT SATISFY THESE RESTRICTIONS AS WELL AS INCREASE THE TIME BETWEEN THE OBSERVATIONS. FIRST WE WILL COMPARE RECENTLY DIGITIZED APOLLO METRIC PHOTOGRAPHS [6] FROM THE 1970'S TO LRO WAC IMAGES WITH SIMILAR LIGHTING CONDITIONS. NEXT WE WILL COMPARE THE NEAR GLOBAL IMAGE DATASET FROM THE SELENE TERRAIN CAMERA (TC) ACQUIRED BETWEEN 2008 AND 2009 TO A SUBSET OF OVER A MILLION PUBLICLY AVAILABLE LRO NAC IMAGES [7]. THESE MULTI-MISSION COMPARISON WILL ENABLE A MORE ROBUST ESTIMATE OF THE CURRENT CRATERING RATE ON THE MOON FOR CRATERS RANGING BETWEEN 20-100 M WHICH IS A KEY DIAMETER RANGE WHEN CALCULATING MODEL AGES OF YOUNG SURFACES USING CRATER SIZE FREQUENCY STATISTICS. FURTHERMORE ANALYSIS OF THESE RECENT SURFACE CHANGES WILL ALSO PROVIDE INSIGHT INTO THE CRATER FORMATION PROCESS THE DISTRIBUTION OF EJECTA AND RESULTING RAYS AS WELL AS AID IN QUANTIFYING THE NUMBER OF CORRESPONDING SECONDARY CHANGES THAT FORM WITH EACH EVENT [5]. METHODOLOGY: WE WILL FIRST SELECT WAC IMAGES ACQUIRED UNDER SIMILAR LIGHTING CONDITION TO THAT OF THE METRIC PHOTOGRAPHS. WE WILL THEN MAP PROJECT AND CO-REGISTER EACH WAC IMAGE TO THE DIGITAL METRIC PHOTOGRAPH CORRECTING ANY PLANIMETRIC OFFSETS BETWEEN THE TWO DATASETS AND ALIGN ALL THE FEATURES TO WITHIN A PIXEL. THEN BY LEVERAGING IMAGE PROCESSING TECHNIQUES DEVELOPED BY OUR TEAM TO PROCESS BEFORE AND AFTER LRO NAC IMAGE PAIRS [5] WE WILL SCAN AND IDENTIFY SURFACE CHANGES IN THE TEMPORAL PAIRS. THE SAME TECHNIQUE WILL BE APPLIED TO LRO NAC AND TC IMAGES. DUE TO THE SIZE OF THE NAC AND TC DATASET A SEMI-AUTOMATIC CHANGE DETECTION PROGRAM WILL BE USED TO LOCATE CHANGES BASED ON REFLECTANCE VARIATIONS AND CHANGES IN SURFACE TEXTURE. THE PROGRAM WAS USED IN [5] AND PROVIDES A LIST OF POTENTIAL NEW FEATURES FOR MANUAL INSPECTION AND CLASSIFICATION. THIS APPROACH REDUCES THE TIME TO MANUALLY INSPECT IMAGE PAIRS BY PROVIDING CROPPED CUTOUTS WITH THE PUTATIVE CHANGES ENABLING RAPID AND SYSTEMATIC PROCESSING OF THOUSANDS OF TEMPORAL PAIRS. BY MEASURING AND TRACKING THE SIZE DISTRIBUTION SPATIAL COVERAGE AND TIME BETWEEN EACH TEMPORAL PAIR WE WILL DERIVE A NEW IMPACT RATE FOR CRATERS<~100 M. RELEVANCE: THIS PROPOSAL IS IN DIRECT RESPONSE TO THE LDAP REQUEST FOR INVESTIGATIONS FOCUSED ON LUNAR CHANGE DETECTION. OUR TEAM WILL IDENTIFY CLASSIFY AND DOCUMENT SURFACE CHANGES USING BEFORE IMAGES PROVIDED BY APOLLO METRIC CAMERA [6] AND SELENE TC [7] AND AFTER IMAGES PROVIDED BY THE LRO NAC AND WAC [3]. ALL DATASETS ARE PUBLICLY AVAILABLE THROUGH THE PLANETARY DATA SYSTEM (PDS) APOLLO IMAGE ARCHIVE AND THE JAXA SELENE DATA ARCHIVE. NOTE REGARDING FLIGHT TEAM MEMBERS: ALL MEMBERS OF THIS PROPOSAL TEAM ARE PARTICIPANTS IN THE LROC INVESTIGATION BUT ARE NOT FUNDED TO CONDUCT MULTI-MISSION ANALYSIS. REFERENCES: [1] NEUKUM ET AL. 2001 SPACE SCI. REV. 96 55-86 [2] HARTMANN W. K. 2005 ICARUS 174 294-320 [3] ROBINSON ET AL. 2010 SPACE SCI. REV. 150: 81-124 [4] ROBINSON ET AL. 2015 ICARUS 252 229-235 [5] SPEYERER ET AL. 2016 NATURE 538 215-218 [6] DOYLE 1970 PHOTOGRAMMETRIC ENGINEERING 36 1039-1044 [7] HARUYAMA ET AL. 2008 EARTH PLANETS SPACE 60 243-255