EUROPA IS A PRIMARY TARGET IN THE SEARCH FOR PAST OR PRESENT LIFE BECAUSE IT IS POTENTIALLY GEOLOGICALLY ACTIVE AND LIKELY POSSESSES A DEEP GLOBAL OCEAN IN CONTACT WITH A ROCKY CORE UNDERNEATH ITS OUTER ICE SHELL. TO REACH THE SUBSURFACE OCEAN WHERE LIFE MAY BE MOST PREVALENT A PROBE WOULD NEED TO PENETRATE THE ICY FORMATION WHILE MOVING THE EXCAVATED MATERIAL BEHIND IT. THIS OPERATION CAN BE ACHIEVED VIA TWO METHODS: THERMAL (MELTING) OR MECHANICAL (CUTTING). MECHANICAL SYSTEMS BREAK THE ICY MATERIAL EFFICIENTLY BUT TRANSPORT ICE CHIPS INEFFICIENTLY. THERMAL SYSTEMS HAVE AN EFFECTIVE CHIP REMOVAL APPROACH BUT A POWER INTENSIVE ICE-MELTING STEP. THE SEARCH FOR LIFE USING SUBMERSIBLE HEATED (SLUSH) DRILL IS A HYBRID THERMOMECHANICAL DRILL PROBE SYSTEM THAT COMBINES THE MOST EFFICIENT ASPECTS OF THESE TWO TECHNIQUES. SLUSH IS 5 M LONG 57 CM DIAMETER PROBE WITH A HEATED DRILL BIT IN FRONT ANTITORQUE CUTTERS ON THE SIDE AND SEVERAL TETHER BAYS ON TOP. THE PROBE IS PARTIALLY FLOODED ONLY CRITICAL SUBSYSTEMS ARE INSIDE A PRESSURE VESSEL; THIS ALLOWS THE PROBE TO SINK RATHER THAN FLOAT. SLUSH UTILIZES A MECHANICAL DRILL TO BREAK THE FORMATION AND PARTIALLY MELTS THE FRAGMENTS TO ENABLE THE EFFICIENT TRANSPORT OF MATERIAL BEHIND THE PROBE. THE RESULTING SLUSH BEHAVES LIKE LIQUID DESPITE BEING PARTIALLY FROZEN ENABLING A SIGNIFICANT REDUCTION OF THE POWER REQUIRED FOR MELTING THE FULL VOLUME OF ICE. FURTHER BECAUSE A MECHANICAL APPROACH GENERATES HIGHER PENETRATION RATES SLUSH CAN REACH THE OCEAN IN A MUCH SHORTER TIME THAN A PURE MELT PROBE. ONCE SLUSH PASSES THROUGH THE HAZARDOUS CRYOGENIC ICE IT COULD USE A PURELY THERMAL APPROACH TO MELT THROUGH THE WARMER ICE WITHOUT THE NEED FOR MECHANICAL CUTTING. SLUSH INCORPORATES THE KILOPOWER REACTOR FOR BOTH THERMAL AND ELECTRICAL NEEDS. THE FISSION REACTOR CAN BE TURNED ON/OFF AND IS SELFMODERATING SIGNIFICANTLY SIMPLIFYING THERMAL MANAGEMENT. THE PROBE IS PHYSICALLY CONNECTED TO A SURFACE LANDER BY A COMMUNICATIONS TETHER HOUSED IN SEVERAL SPOOL BAYS THAT ARE LEFT BEHIND IN THE ICE ONCE THE SPOOL IS DEPLETED. THIS ALLOWS EACH TETHER SECTION TO BE PURPOSE-DESIGNED. FOR EXAMPLE THE TOP SECTION WHICH MAY SEE 150 KPA SHEAR STRESSES ON A DIURNAL CYCLE WILL BE REINFORCED WITH KEVLAR. LEAVING THE SPOOLS BEHIND ALSO SHORTENS THE PROBE LENGTH AS IT DESCENDS MAKING PENETRATION MORE EFFICIENT. WHILE KEVLAR REINFORCEMENT AND THE REFROZEN CHANNEL LEFT BEHIND BY THE PROBE MAY PROVIDE PROTECTION FROM THE DIURNAL STRESS ENVIRONMENT IF THE TETHER DOES BREAK BROKEN SECTIONS CAN BE USED AS TUNABLE TETHER FOR COMMUNICATION. RF AND ACOUSTIC COMMUNICATION WILL BE INVESTIGATED AS BACKUP SYSTEMS POTENTIALLY INCORPORATING TRANSCEIVERS INTO EACH SPOOL SECTION. UNDER SESAME WE WILL PERFORM THE FOLLOWING TASKS: 1. PERFORM FIRST ORDER ARCHITECTURE DESIGN AND IDENTIFY CRITICAL TECHNOLOGIES FOR SLUSH. 2. PERFORM ITERATIVE BREADBOARDING/TESTING OF CRITICAL SUBSYSTEMS UNDER REALISTIC EUROPAN CONDITIONS AND DOWNSELECT TO MOST FAVORABLE SOLUTIONS. PERFORM MODELLING OF CRITICAL SUBSYSTEMS IF TESTING IS NOT FEASIBLE. VALIDATE MODELS VIA TESTING IF POSSIBLE. 3. UPDATE SLUSH SYSTEM ARCHITECTURE BY INCORPORATING DOWNSELECTED SUBSYSTEMS 4. DEVELOP TRL4 PROTOTYPE HARDWARE AND TEST IN 3.5 M CRYO VACUUM CHAMBER AND 5 M FREEZER IN EUROPA ANALOG MATERIALS. 5. USE EXPERIMENTAL DATA TO VALIDATE MODELS AND EXTRAPOLATE TO FLIGHT-LIKE SYSTEM. KRIS ZACNY (PI) WILL BE RESPONSIBLE FOR THE OVERALL PROJECT. HE WILL BE ASSISTED BY SCIENCE LEAD (CHRISTOPHE SOTIN) ICE SHELL ENVIRONMENT SPECIALIST (SAM HOWELL) THERMAL (SAM HOWELL SEIICHI NAGIHARA PAUL CHOW) COMM (MIKE TIPTON) AND SYSTEMS LEAD (GALE PAULSEN DAVE SMYTH). ALL WILL PARTICIPATE IN REVIEWS AND TESTS. ALL HARDWARE DEVELOPMENT FAB. ASSEMBLY AND TESTS WILL TAKE PLACE IN HONEYBEE S FACILITIES IN PASADENA CA.