THE PRIMARY OBJECTIVE OF CUBESAT: INNER RADIATION BELT EXPERIMENT (CIRBE) IS TO UNDERSTAND BETTER THE FORMATION AND DECAY OF THE INNER BELT (L<2) ELECTRONS (100S OF KEV TO MULTIPLE MEV) AND TO DETERMINE THE INTENSITY AND DYNAMIC VARIATIONS OF THESE ELECTRONS WITH A STATE-OF-ART INSTRUMENT FITTED INTO A CUBESAT IN A HIGHLY INCLINED LOW EARTH ORBIT (LEO). METHODOLOGY. CIRBE IS IN SOME WAYS SIMILAR TO OUR PREVIOUS VERY SUCCESSFUL CUBESAT (CSSWE) BUT DIFFERS IN THAT IT WILL HAVE EXTREME FINE ENERGY RESOLUTION (100S OF ENERGY CHANNELS INSTEAD OF 3). WE PROPOSE TO ADVANCE THE EXISTING REPTILE DESIGN BY INCORPORATING FULL PULSE HEIGHT ANALYSIS (PHA) WHICH HAS BEEN ROUTINELY PERFORMED ON REPT AND ADDITIONAL ANTI-COINCIDENCE TECHNIQUE WHICH HAS BEEN IMPLEMENTED IN THE FRONT DETECTOR OF REPT SUCH THAT IT WILL HAVE THE FINE ENERGY RESOLUTION PLUS MUCH CLEANER MEASUREMENTS BUT STILL FIT IN A 3U CUBESAT. PHA WILL BE PERFORMED ONBOARD AND ONLY THE FINAL RESULTS: INTENSITY ENERGY SPECTRUM PITCH ANGLE DISTRIBUTION (PAD) WILL BE DOWNLOADED.