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THE MIT SPACE TELECOMMUNICATIONS ASTRONOMY AND RADIATION LAB HAS BEEN DEVELOPING LOW-COST COMPACT NANOSATELLITE COMMUNICATIONS TRANSMIT TERMINALS AND GROUND STATIONS SINCE 2012 ALONG WITH PROVIDING TECHNICAL AND COMMUNICATIONS TRAINING FOR THE SUPPORTING STUDENTS AND PUBLICATIONS TO DISSEMINATE KNOWLEDGE. THE LAB IS NOW WORKING ON FULL TRANSCEIVER TERMINALS AS PART OF THE CUBESAT LASER INFRARED CROSSLINK (CLICK) MISSION. THE GOAL IS TO DEMONSTRATE A LOW-COST LOW-COMPLEXITY TERMINAL THAT PROVIDES>20 MBPS CROSSLINKS WITH INDEPENDENT CM-LEVEL RANGING AT SEPARATIONS OF>500 KM FOR USE IN CONSTELLATIONS AND SWARMS. CLICK IS FULL-DUPLEX USING BOTH COARSE BODY-POINTING AS WELL AS A MEMS FAST STEERING MIRROR (FSM) FOR PRECISION POINTING AND WAVELENGTH DIVISION MULTIPLEXES TWO C-BAND CHANNELS (1537 NM AND 1565 NM). HOWEVER A KEY CHALLENGE REMAINS MOVING FORWARD WITH THESE POINT-TO-POINT LASERCOM TERMINALS: HOW TO DO BROADCAST MULTI-CAST AND MULTI-POINT-TO-POINT COMMUNICATIONS WITH A NANOSATELLITE FREE SPACE OPTICAL TERMINAL. WE PROPOSE TO ADDRESS THIS WITH THE MINIATURE OPTICAL STEERED ANTENNA FOR INTERSATELLITE COMMUNICATION (MOSAIC) TERMINAL. TO ENABLE FASTER SWITCHING BETWEEN COMMUNICATION PARTNERS ALLOW SATELLITES TO POINT THEIR PAYLOADS AND COMMUNICATION SYSTEMS INDEPENDENTLY AND CONCURRENTLY AND TO MINIMIZE THE MECHANICAL COMPONENTS IN THE SYSTEM WE PROPOSE TO DEVELOP A NEXT-GENERATION FRONT END FOR CLICK THAT IS AN OMNI-OPTICAL ANTENNA THAT SUPPORTS MULTIPLE ACCESS. THE MOSAIC TERMINAL IS DESIGNED TO HAVE HEMISPHERICAL COVERAGE. IF NECESSARY A MISSION COULD PLAN FOR RAPID HANDOFF BETWEEN TWO UNITS MOUNTED ON OPPOSITE SIDES OF A SPACECRAFT. MOSAIC WILL USE ELECTRO-OPTICS NAMELY A SERIES OF STAGED LIQUID LENS BEAM STEERING DEVICES COMBINED WITH STANDARD OPTICS SUCH AS A FISHEYE LENS TO ACHIEVE TWO-AXIS WIDE AREA COVERAGE WHILE RETAINING LOW DIVERGENCE FOR NARROW BEAMWIDTH COMMUNICATION LINKS. BECAUSE THE BEAM DIVERGENCE IS CONTROLLED BY ONE OF THE STAGED LIQUID LENSES MOSAIC WILL BE DEVELOPED TO BE ABLE TO SUPPORT BOTH A WIDER-BEAMWIDTH BEACON CAPABILITY FOR POINTING ACQUISITION AND TRACKING AS WELL AS ESTABLISHMENT OF THE HIGHER RATE NARROWER BEAMWIDTH COMMUNICATION LINKS. WE WILL WORK TO DEVELOP SPACE-QUALIFIABLE MODULES OF STAGED LENS ARRAYS THAT FIT INTO NANOSATELLITES FOR DEMONSTRATION AND CAN SUPPORT UP TO TEN DIFFERENT INDEPENDENT USERS. WE WILL ANALYZE BEAM STEERING RESPONSIVITY COMPARED WITH EXPECTED ENVIRONMENTAL FACTORS DISTURBANCES AND SLEW RATES FOR REPRESENTATIVE APPLICATIONS IN LEO GEO AND DEEP SPACE AND WILL CHARACTERIZE THE THROUGHPUT OF THE LENS RELAY. WE WILL ALSO CONSIDER INCLUDING MEMS TECHNOLOGY USED TO AUGMENT THE LIQUID LENSES SUCH AS A COMPACT MEMS SHUTTER OR MODULATED RETROREFLECTOR ARRAY TO ENABLE SPATIAL FILTERING OF THE WIDE-ANGLE TERMINAL AND MEMS FAST STEERING MIRRORS OR DEFORMABLE MIRRORS (BOTH CURRENTLY IN USE ON OTHER NANOSATELLITE FLIGHT PROJECTS IN STAR LAB) TO POTENTIALLY COUPLE RECEIVED BEAMS TO OPTICAL FIBER FOR PREAMPLIFICATION OR COHERENT DEMODULATION. THE MOSAIC TERMINAL WILL ENABLE BROADCAST MULTIPLE-ACCESS MULTI-POINT-TO-POINT SMALL SATELLITE FREE SPACE OPTICAL COMMUNICATIONS APPLICATIONS.

$499,947FY2020National Aeronautics and Space AdministrationNASA

Massachusetts Institute Of Technology, Cambridge MA

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