SCIENCE OBJECTIVES: RECENT MODELING OF THE FORMATION OF ORIENTALE BY THE PI (JOHNSON ET AL. 2015) INDICATES THAT THE SPACING AND LOCATION OF BASIN RINGS DEPEND ON THE STATE OF THE LUNAR LITHOSPHERE. THE HIGH-RESOLUTION LUNAR GRAVITY FIELD PROVIDED BY THE GRAVITY RECOVERY AND INTERIOR LABORATORY (GRAIL) MISSION AND LUNAR TOPOGRAPHY FROM THE LUNAR ORBITER LASER ALTIMETER (LOLA) INSTRUMENT OFFER AN EXCEPTIONAL OPPORTUNITY TO INVESTIGATE LUNAR BASIN RINGS TO GAIN VALUABLE INSIGHT INTO THE STRUCTURE OF THE LUNAR LITHOSPHERE. WE PROPOSE TO MODEL THE OBSERVED GRAVITATIONAL AND TOPOGRAPHIC SIGNATURES OF LUNAR BASIN RINGS TO INVESTIGATE THE SPATIAL AND TEMPORAL VARIATION OF THE STRUCTURE OF THE LUNAR LITHOSPHERE. IN TASK 1 WE WILL USE GRAIL GRAVITY DATA AND LOLA TOPOGRAPHY DATA IN ORDER TO CONSTRAIN THE SUBSURFACE STRUCTURE OF PEAK RING AND MULTI-RING BASINS. MODELS OF THE CRUSTAL STRUCTURE OF THE BASINS WILL BE USED TO QUANTIFY THE DIP AND DISPLACEMENT ACROSS INDIVIDUAL FAULTS. COMPARISONS BETWEEN BASINS AND ASYMMETRIES WITHIN INDIVIDUAL BASINS WILL PROVIDE INFORMATION ON THE SENSITIVITY OF THE RING FAULT CHARACTERISTICS TO TARGET PROPERTIES SUCH AS CRUSTAL THICKNESS AND HEAT FLOW. IN TASK 2 WE WILL STUDY THE STRUCTURE OF THE RINGS THAT CHARACTERIZE MULTI-RING BASINS BY FORWARD MODELING THEIR GRAVITATIONAL SIGNATURES. THIS TASK WILL INCLUDE MODELING THE FORMATION OF MULTI-RING BASINS TO DETERMINE HOW THE GRAVITY SIGNATURES LOCATIONS SPACING AND OFFSETS OF BASIN RINGS DEPEND ON THE THICKNESS OF THE LUNAR LITHOSPHERE IMPACTOR SIZE AND PRE-IMPACT CRUSTAL THICKNESS. IN TASK 3 WE WILL COMPARE OUR FORWARD MODELS FROM TASK 2 TO THE OBSERVED GRAVITY SIGNATURES CRUSTAL STRUCTURE DERIVED IN TASK 1 LOCATIONS SPACING AND OFFSETS OF THE RINGS OF OLD AND YOUNG BASINS. IN ALL TASKS WE WILL FOCUS ON KEY BASINS CHOSEN TO BE REPRESENTATIVE OF DISTINCTIVE IMPACT CONDITIONS. THE FIRST FOCUS OF THE WORK WILL BE ON THE ORIENTALE BASIN. ADDITIONAL ANALYSES WILL FOCUS ON THE EFFECTS OF DIFFERENT TARGET PROPERTIES BY COMPARING BASINS THAT DIFFER PRIMARILY IN A SINGLE KEY PARAMETER. THE EFFECT OF HEAT FLOW WILL BE INVESTIGATED LOOKING AT TWO SIMILARLY SIZED BASINS WITHIN AND OUTSIDE OF THE PKT (E.G. IMBRIUM AND ORIENTALE) OR TWO SIMILARLY SIZED BASINS FORMED IN THE PRE-NECTARIAN AND NECTARIAN/IMBRIAN (E.G. SMITHII AND ORIENTALE). THE EFFECT OF CRUSTAL THICKNESS WILL BE INVESTIGATED BY COMPARING TWO SIMILARLY SIZED BASINS IN THE THICK CRUST OF THE FARSIDE HIGHLAND AND THE THIN CRUST OF THE SOUTH POLE-AITKEN BASIN (E.G. HERTZSPRUNG AND APOLLO). THE EFFECT OF IMPACT ENERGY AND THE PEAK-RING TO MULTI-RING BASIN TRANSITION WILL BE INVESTIGATED BY FOCUSING ON BASINS OF DIFFERENT SIZE (E.G. KOROLEV HERTZSPRUNG AND ORIENTALE).