SCIENTIFIC GOAL: THE LATEST DECADAL SURVEY MENTIONS EUROPA AS THE HIGHEST PRIORITY DESTINATION IN THE OUTER SOLAR SYSTEM AS POTENTIAL PLANETARY HABITAT . AMONG THE GALILEAN SATELLITES EUROPA S OCEAN IS EXPECTED TO BE FOUND AT THE SHALLOWEST DEPTH BENEATH THE ICE SHELL BECAUSE OF TIDAL HEATING AND THE RADIOGENIC HEATING FROM THE ROCKY INTERIOR BENEATH THE OCEAN. IT IS REASONABLE TO EXPECT SEAFLOOR VOLCANISM AND HYDROTHERMAL ACTIVITY THAT COULD PROVIDE NUTRIENTS AND ENERGY TO SUPPORT METABOLISM . MEASUREMENT OF THE HEAT TRANSPORT THROUGH THE ICE SHELL IS CRITICAL IN FURTHER UNDERSTANDING THE THERMAL EVOLUTION OF THE MOON S INTERIOR AND THE POSSIBLE ECOSYSTEMIC FRAMEWORK OF THE SUBSURFACE OCEAN. THE HEAT FLOW MEASUREMENT WILL ALSO CONSTRAIN THE THICKNESS OF THE ICE SHELL. NASA IS PLANNING A LANDER MISSION TO EUROPA. WE PROPOSE TO DESIGN A HEAT FLOW PROBE THAT CAN BE ROBOTICALLY DEPLOYED FROM A LANDER ON THE SURFACE OF EUROPA AND THE OTHER ICY MOONS SUCH AS ENCELADUS FOR THE PURPOSE OF MEASURING THE ENDOGENIC HEAT RELEASED FROM THE ICE SHELL. METHODOLOGY: THE UPPERMOST PORTION OF EUROPA S ICE SHELL TRANSPORTS HEAT BY CONDUCTION. CONDUCTIVE HEAT FLOW CAN BE OBTAINED AS THE PRODUCT OF TWO SEPARATE MEASUREMENTS OF THE THERMAL GRADIENT AND THE THERMAL CONDUCTIVITY OF THE DEPTH INTERVAL PENETRATED BY A PROBE. ON EARTH A ROTARY OR PERCUSSIVE DRILL IS USED TO EXCAVATE A HOLE AND THEN A HEAT FLOW PROBE IS INSERTED. DRILL PIPE SECTIONS ARE ADDED UNTIL THE HOLE REACHES THE TARGETED DEPTH. ON A ROBOTIC PLANETARY MISSION HOWEVER SUCH TECHNIQUE IS NOT POSSIBLE DUE TO THE LIMITED SPACE AVAILABLE ON THE LANDER AND THE COMPLEXITY OF EXTENDING THE DRILL PIPE ONE SECTION AT A TIME. PREVIOUSLY FOR USE ON EARTH S MOON OUR GROUP DEVELOPED A COMPACT (SHOEBOX-SIZE 1-KG) HEAT FLOW PROBE DEPLOYMENT MECHANISM IN WHICH THERMAL SENSORS WERE EMBEDDED ON A FLEXIBLE STEM THAT SPOOLED OUT LIKE A STEEL TAPE MEASURE AS IT PENETRATED DEEPER INTO THE SUBSURFACE. WE WILL BASE THE EUROPA HEAT FLOW PROBE ON A SIMILAR DEPLOYMENT MECHANISM. THE LEADING END OF THE STEM REQUIRES A MECHANISM FOR EXCAVATING THE ICE. WE WILL TEST TWO APPROACHES. THE FIRST IS COMBINATION OF A SMALL ROTARY AUGER AND A GAS JET TO BLOW AWAY THE CUTTINGS AND THE SECOND IS TO SUBLIME THE ICE WITH A HEATER (SIMPLER BUT POSSIBLY MORE ENERGY-INTENSIVE). AS THE STEM SPOOLS OUT IT IS GUIDED TO FORM A CYLINDER OF 1.5-CM DIAMETER IN ORDER TO GAIN MECHANICAL STRENGTH. AFTER THE STEM REACHES A DESIRED DEPTH THE DEPLOYMENT MECHANISM IS TURNED OFF AND THE SENSORS EMBEDDED ON THE STEM CARRY OUT NECESSARY MEASUREMENTS. THIS PROJECT WILL LAST 3 YEARS. OUR ENTRY AND EXIT TRLS ARE 1 AND 3 RESPECTIVELY. IN THE FIRST YEAR WE WILL CONDUCT EXTENSIVE TRADE STUDIES FOR THE TWO ICE-EXCAVATION APPROACHES. WE WILL ALSO PERFORM NUMERICAL SIMULATIONS ON THE PROBE DEPLOYMENT ON EUROPA S SURFACE IN CONSTRAINING THE KEY PARAMETERS IN DESIGNING THE PROBE SUCH AS THE DEPTH OF PENETRATION TIME DURATION OF THE THERMAL MEASUREMENTS MEASUREMENT ACCURACY POWER CONSUMPTION ETC. IN THE 2ND YEAR WE WILL BREAD-BOARD KEY COMPONENTS. WE WILL ALSO DEVELOP A SUITABLE SIMULANT FOR THE ICE ON EUROPA. PREVIOUS STUDIES SUGGEST THAT THE ICE ON EUROPA IS POROUS AND MUCH LESS DENSE THAN SOLID ICE. WE WILL DEVELOP A PROCEDURE FOR MAKING SUCH ICE IN A LAB WITH CONSISTENCY. IN THE THIRD YEAR WE WILL ASSEMBLE A TRL-3 PROTOTYPE OF THE HEAT FLOW PROBE AND PERFORM PENETRATION TESTS ON THE ICE SIMULANT PLACED IN OUR EXISTING 3.5 M TALL THERMAL VACUUM CHAMBER AND 6 M TALL WALK-IN FREEZER. WE WILL CONCLUDE THE PROJECT BY LAYING OUT A PATH FORWARD FOR HIGHER TRL. RELEVANCE: THE PICASSO CALL STATES INSTRUMENTS FOCUSED ON DETECTING EXTANT LIFE IN THE OCEAN WORLDS (E.G. ENCELADUS EUROPA ) ARE ESPECIALLY OF INTEREST . THE HEAT FLOW PROBE PROPOSED HERE WILL BE USEFUL FOR CONSTRAINING THE ECO-SYSTEMIC FRAMEWORK OF THE SUBSURFACE OCEAN OF EUROPA AND CONSTRAIN THE THICKNESS OF THE ICE SHELL.