UTILIZING OUR RECENT TECHNOLOGICAL ADVANCES IN X-RAY OPTICS AND SENSORS CUBEX WILL COMBINE HIGH ANGULAR RESOLUTION (<1') MINIATURE WOLTER-I X-RAY OPTICS (MIXO) WITH A COMMON FOCAL PLANE ALLOWING ACCESS TO HIGH SPECTRAL RESOLUTION (<200 EV AT 6 KEV) CMOS X-RAY SENSORS FOR XRF IMAGING AND A HIGH TIMING RESOLUTION (<1 US) SDD X-RAY SENSOR FOR XNAV WITH NO MOVING PARTS. THE INITIAL CONCEPT FOR CUBEX WILL BE DESIGNED WITH THE MOON AS THE PRIMARY TARGET FOR XRF IMAGING IN A 12U FORM FACTOR (1X2X6U). THE MOON IS A NATURAL FIRST STEP FOR THE CUBESAT/SMALLSAT CONCEPT DEVELOPMENT FOR BOTH XRF IMAGING AND XNAV. THE RELATIVE PROXIMITY OF THE MOON ENABLES A STRAIGHTFORWARD EVALUATION OF THE XNAV PERFORMANCE THROUGH DSN. TO FACILITATE THE UNPRECEDENTED HIGH RESOLUTION (~0.6-2.3 KM) MAP OF THE ELEMENTAL ABUNDANCE OF VARIOUS REGIONS OF INTEREST ON THE MOON (E.G. CRATERS OF DIVERSE SIZES CAN POTENTIALLY REVEAL THE COMPOSITION OF THE LUNAR CRUST) CUBEX WILL STAY AT HIGH ALTITUDE (~2000-8000 KM) ELLIPTICAL POLAR LUNAR ORBITS OF LOW-MAINTENANCE FOR 1 YEAR FROM THE LAUNCH NEAR THE NEXT SOLAR MAXIMUM (~2023-2027). THE PROPOSED CONCEPT WILL ALLOW MULTIPLE FLEXIBLE CONFIGURATIONS DEPENDING ON SCIENCE AND ENGINEERING GOALS. WE WILL ALSO STUDY A LARGER 24U CUBEX CONFIGURATION (2X2X6U) WITH A MORE POWERFUL TELESCOPE.