VIABILITY OF A CALIBRATION SATELLITE FOR SPACE SCIENTIFIC MISSIONS OF THE COSMIC MICROWAVE BACKGROUND POLARIZATION

SCIENTIFIC SPACE MISSIONS FOR THE COSMIC MICROWAVE BACKGROUND (CMB) STUDY HAVE BEEN HAPPENING FROM COBE TO PLANCK, WITH INCREASING RESOLUTION AND SENSITIVITY OF THEIR DETECTORS. AT PRESENT THERE ARE SEVERAL PROJECTS STILL NOT FUNDED BY THE SPACE AGENCIES --CORE (ESA), INDOCORE (ESA/ISRO), PICO (NASA)-- AND ONE IN PHASE A --LITEBIRD (JAXA)--, ALL OF THEM WITH THE MAIN OBJECTIVE OF DETECTING THE PRIMORDIAL BACKGROUND OF GRAVITATIONAL WAVES THROUGH THE PRECISE MEASUREMENT OF THE CMB POLARIZATION. FOR INSTRUMENTS PRESENTING THE REQUIRED LEVEL OF SENSITIVITY, IT IS NECESSARY TO DEVELOP NEW CALIBRATION STRATEGIES THAT ALLOW THE REDUCTION OF SYSTEMATIC ERRORS DOWN TO THE REQUIRED LEVEL, TO BE ABLE TO OPTIMALLY EXPLOIT THE LOW NOISE OF THE PROPOSED INSTRUMENTATION. UNTIL NOW, IN THE CMB SPACE MISSIONS, PLANETS, GALACTIC OBJECTS AS THE CRAB NEBULA AND EVEN THE MOON OR THE SUN, HAVE BEEN USED AS CALIBRATION SOURCES. HOWEVER THE EMITTED POLARIZED LIGHT OF THESE SOURCES IS NOT KNOWN IN THE OVERALL FREQUENCY RANGE OR WITH THE REQUIRED ACCURACY. WE PROPOSE A VIABILITY STUDY OF A LOW-COST AND SMALL ANCILLARY CALIBRATION SATELLITE THAT WOULD ALLOCATE, AS PAYLOAD, A SET OF SIGNAL SOURCES COVERING THE OVERALL OPERATION FREQUENCY BAND OF THE PARTICULAR SPACE MISSION¿S INSTRUMENTATION. THIS SATELLITE WOULD ALLOW KNOWING THE CALIBRATION SOURCE WITH THE ACCURACY REQUIRED TO ACHIEVE THE SCIENTIFIC GOALS. COST REDUCTION POSSIBILITIES, OFFERED BY THE USE OF PREDEFINED PLATFORMS AS CUBESAT, WILL BE STUDIED, AIMING FOR A BUDGET OF ABOUT SEVERAL MILLION EUROS. IN THIS PROJECT WE WILL FOCUS IN THE PROPOSAL LITEBIRD TO STUDY THE VIABILITY OF THE CALIBRATION SATELLITE, BUT THIS STUDY CAN BE EASILY APPLIED TO THE REST OF PREVIOUSLY CITED MISSIONS AND EVEN TO OTHER SCIENTIFIC MISSIONS OPERATING IN DIFFERENT FREQUENCY BANDS.