AQUEOUS OCEANS NOW APPEAR TO BE ABUNDANT IN THE SOLAR SYSTEM. THE ACCEPTED PRESENCE OF SOLUTES IN THESE HYDROSPHERES REPRESENT THE NEXT FRONTIER IN OUR UNDERSTANDING OF THE CHEMICAL-PHYSICAL-THERMAL EVOLUTION PLANETARY MAGNETISM AND CURRENT INTERIOR STRUCTURE OF ICY WORLDS. JUST AS EXPERIMENTALLY BASED GEOCHEMICAL CALCULATIONS HAVE BECOME AN INTEGRAL PART OF MANY BRANCHES OF THE EARTH AND ENVIRONMENTAL SCIENCES AQUEOUS GEOCHEMISTRY IS BECOMING AN INCREASINGLY IMPORTANT TOOL FOR PLANETARY SCIENCE. THE THERMODYNAMICS OF HIGH PRESSURE AQUEOUS SOLUTIONS AND THE EQUILIBRIA WITH ICE POLYMORPHS HAVE NOT YET BEEN ADEQUATELY EXPLORED. NEW DATA ARE REQUIRED TO BUILD ACCURATE MODELS OF PLANETARY INTERIORS STRUCTURE GEOCHEMISTRY AND GEODYNAMICS. THROUGH THIS FUNDING REQUEST WE AIM TO 1) OBTAIN HIGH PRECISION EXPERIMENTAL DATA TO CONSTRAIN THE THERMODYNAMICS OF AQUEOUS SOLUTIONS IN POORLY EXPLORED REGIMES RELEVANT TO OUTER SOLAR SYSTEM ICY WORLDS AND OTHER BRANCHES OF PLANETARY SCIENCE 2) FURTHER DEVELOP THE NUMERICAL FRAMEWORK FOR THE REPRESENTATION AND USE OF ACQUIRED DATA AND 3) USE THE DEVELOPED FRAMEWORK TO STUDY THE INFLUENCE OF SOLUTES ON DEEP HYDROSPHERE PROCESSES AND ON THE STABILITY OF OCEANS THROUGH GEOLOGICAL TIMESCALES AND SUBSEQUENT STRUCTURE AND CHEMISTRY EVOLUTION OF ICY WORLDS. THE FUNDING REQUEST IS ASSOCIATED WITH THREE PRIMARY TASKS. TASK 1. (EXPERIMENTAL CHEMISTRY) BY USING AVAILABLE ULTRASONIC AND OPTICAL HIGH PRESSURE APPARATUSES WE WILL MEASURE THE SPEED OF SOUND OF NA-MG-SO4-CL AQUEOUS SOLUTIONS AT PRESSURES TO 6000 MPA AND TEMPERATURES FROM 100 K TO 600 K. IN PARALLEL EQUILIBRIUM WITH HIGH PRESSURE ICE POLYMORPHS WILL BE INVESTIGATED USING OPTICAL HIGH PRESSURE CELLS AND EQUATIONS OF STATES OF THESE ICES WILL ALSO BE INVESTIGATED TO BETTER CONSTRAIN AQUEOUS ENVIRONMENTS STABILITY. TASK 2. (THEORETICAL CHEMISTRY) GIBBS ENERGY SURFACES AS A FUNCTION OF P T AND COMPOSITION WILL BE REPRESENTED USING DATA FROM TASK 1. PITZER PARAMETERS THAT ENABLE COMPREHENSIVE GEOCHEMICAL CALCULATIONS AT P-T RANGES RELEVANT FOR PLANETARY INTERIORS (E.G. SOLIDLIQUID AND SOLID-GAS TRANSITIONS DISSOLUTION AND PRECIPITATION) WILL BE REPORTED. TASK 3. (PLANETARY MODELING) WE WILL INCORPORATE OUR SOLUTION AND ICE PARAMETERS INTO PLANETARY MODELS TO ASSESS THE LARGE-SCALE EFFECTS OF SALT CHEMISTRY IN OCEAN WORLDS USING THE PLANETPROFILE MODEL. SIGNIFICANCE TO SOLAR SYSTEM WORKINGS: THIS PROJECT IDENTIFIES AND ADDRESSES A NEED FOR PLANETARY GEOCHEMICAL DATA IN A BROADER RANGE OF P T AND CONCENTRATION. RESULTING CALCULATIONS AND DATA FRAMEWORKS WILL BE SHARED IN A WAY THAT IDENTIFIES NEW OR NEEDED MEASUREMENTS AND ENCOURAGES PARTICIPATION BY OTHER LABS COLLECTING COMPLEMENTARY DATA.