WE PROPOSE TO BUILD AND TEST A PROTOTYPE P-BAND (70 CM WAVELENGTH) BEAMFORMING P-BAND SYNTHETIC APERTURE RADAR(SAR) CALLED SPACE EXPLORATION SAR (SESAR). MANY KEY SCIENCE OBJECTIVES REQUIRE THE ABILITY TO PENETRATE THROUGH METERS OF DUST AND REGOLITH TO EXPOSE BURIED TERRAIN. OUR SCIENCE OBJECTIVES ARE FOCUSED ON THE MOON AND MARS BUT THE RADAR COULD BE USED FOR DISCOVERY OR NEW FRONTIERS MISSIONS TO VENUS MERCURY ASTEROIDS OR OTHER OBJECTS WHERE SEVERAL METERS OF SURFACE PENETRATION ARE REQUIRED. SESAR WILL BE ABLE TO DETECT AND MAP BURIED ICE DEPOSITS INCLUDING USING A SOUNDING MODE TO MEASURE THE DEPTHS TO SUCH DEPOSITS. IT WILL BE ABLE TO RESOLVE THE RECURRING SLOPE LINEA ON MARS TO SEARCH FOR EVIDENCE OF SALTS OR BRINES. SESAR WILL PENETRATE THROUGH DUST TO REVEAL BURIED FLUVIAL CHANNELS AND LAKE DEPOSITS ON MARS AND IT WILL ALSO PROVIDE THE CAPABILITY FOR DETAILED MORPHOLOGICAL STUDIES OF VOLCANIC DEPOSITS. SESAR WILL ALSO BE ABLE TO SEARCH FOR LAVA TUBES AND CAVES. SESAR IS FULLY-POLARIMETRIC WITH METER-SCALE SPATIAL RESOLUTIONS AND HAS MODES FOR ALTIMETRY SCATTEROMETRY AND NADIR SOUNDING. THE BEAMFORMING CAPABILITY ALSO ALLOWS THE LOOK ANGLE TO BE CHANGED WITHOUT ROLLING THE SPACECRAFT TO ACQUIRE OPTIMUM DATA ON SLOPED SURFACES AND FOR POLARIMETRY MODELING. THE PROTOTYPE WILL LEVERAGE PROVEN ADVANCED RADAR TECHNOLOGIES AND TECHNIQUES DEVELOPED AT NASA/GODDARD SPACE FLIGHT CENTER THROUGH PICASSO IIP SBIR AND GSFC INTERNAL RESEARCH AND DEVELOPMENT PROGRAM INVESTMENTS. THESE ADVANCEMENTS INCLUDE DIGITAL BEAMFORMING BROADBAND/LIGHT-WEIGHT ANTENNA ARRAYS DIGITAL MULTI-CHANNEL RADAR WAVEFORM GENERATOR/DATA PROCESSORS ONBOARD RADAR PROCESSING LOW-POWER RF ELECTRONICS AND RADAR SYSTEM DEMONSTRATIONS WITH AIRCRAFT-BASED RADAR ARCHITECTURES. SESAR EMPLOYS A MODULAR APPROACH THAT ALLOWS THE ANTENNA AND RADAR ELECTRONICS TO BE SCALED TO WORK FOR MULTIPLE PLANETARY TARGETS. BUILDING AND TESTING THE SESAR PROTOTYPE WILL PROVIDE DEVELOPMENT OF INNOVATIVE TECHNOLOGIES THAT IMPROVE INSTRUMENT MEASUREMENT CAPABILITIES AS DESCRIBED IN THE MATISSE SOLICITATION. NO OTHER PLANETARY RADAR MISSIONS HAVE OPERATED AT P-BAND OR HAVE THE CAPABILITIES (RESOLUTION FULL POLARIMETRY FLEXIBILITY) OF THE SESAR INSTRUMENT. NASA S INVESTMENT IN THIS TECHNOLOGY WILL THEREFORE BE KEY IN MAKING FUTURE PLANETARY RADAR MISSIONS FEASIBLE AND IN ADDRESSING THE LARGE NUMBER OF DECADAL SURVEY AND EXPLORATION ANALYSIS GROUP SCIENCE GOALS THAT REQUIRE IMAGING OF THE SUBSURFACE. WE WILL HELP ACHIEVE THESE GOALS BY BRINGING THE SESAR INSTRUMENT FLIGHT READINESS TO A TRL 6 BY THE END OF THE PROJECT.