10 CASSINI IMAGING SCIENCE SUBSYSTEM (ISS) OBSERVATIONS HAVE REVEALED WIDESPREAD DARKENING OF TITAN'S SURFACE BELIEVED TO BE THE RESULT OF RAINFALL, FIRST IN 2005 NEAR TITAN'S SOUTH POLE (TURTLE ET AL., 2009, GRL 36), AND LATER IN 2009 IN TITAN'S TROPICS (TURTLE ET AL., 2011, SCIENCE 331). COMBINED CASSINI ISS AND VISUAL AND INFRARED MAPPING SPECTROMETER (VIMS) OBSERVATIONS REVEALED THAT, FOLLOWING THIS DARKENING, THE ALBEDO OF THE PUTATIVE WETTED SURFACES INCREASED, BEYOND EVEN THEIR ORIGINAL ALBEDO (BARNES ET AL., 2013, PLANET. SCI. 2 SODERBLOM ET AL., 2014, DPS). IN THE TROPICS EVENT, THE BRIGHTNESS THEN SLOWLY FADED TO A PRE-RAIN BRIGHTNESS OVER 10 MONTHS (BARNES ET AL., 2013), WHILE THE BRIGHTENED SURFACE IN THE SOUTH POLAR CASE WAS STILL BRIGHT COMPARED TO ITS SURROUNDING FOUR YEARS AFTER THE INITIAL RAIN EVENT, AND MORE THAN 2 YEARS AFTER THE INCREASED ALBEDO WAS FIRST OBSERVED (SODERBLOM ET AL., 2014). BASED ON THE TIMESCALE AND MAGNITUDE OF THE ALBEDO CHANGES, AND THE CORRELATIONS BETWEEN THE TIMESCALE AND TEMPERATURE (INFERRED FROM LATITUDE), OUR PREFERRED HYPOTHESIS IS THAT HYDROCARBONS PRECIPITATED ONTO TITANS SURFACE FROZE VIA EVAPORATIVE COOLING. WE PROPOSE A THREE-YEAR INVESTIGATION THAT COMBINES DATA ANALYSIS AND LABORATORY SIMULATIONS TO DETERMINE WHETHER METHANE-ETHANE MIXTURES, IN EQUILIBRIUM WITH A 1.5 BAR NITROGEN ATMOSPHERE, CAN FREEZE ON TITAN'S SURFACE, AND IF THE CASSINI OBSERVATIONS ARE CONSISTENT WITH SUCH AN INTERPRETATION. WE HAVE CONDUCTED INITIAL EXPERIMENTS WITH PURE METHANE AND ETHANE (E.G., GAINOR ET AL., 2014, LPSC), DEMONSTRATING THE TECHNIQUES NEEDED FOR THIS WORK. THE RESULTS OF THIS WORK WILL HAVE SIGNIFICANT AND BROAD-REACHING IMPLICATIONS REGARDING TITAN'S GEOLOGY, HYDROCARBON CYCLE, AND TOTAL HYDROCARBON BUDGET. THAT TITAN'S RAIN MAY FREEZE ON THE SURFACE BEGS THE QUESTION, "IF SO, WHY DON'T TITAN'S LARGER LAKES AND SEAS FREEZE?" OUR WORK WILL HELP TO UNDERSTAND THE CONDITIONS (E.G., MIXING RATIO) UNDER WHICH METHANE-ETHANE MIXTURES MAY OR MAY NOT FREEZE, THUS PROVIDING KEY INFORMATION TO ADDRESS SUCH QUESTIONS. OUR PROPOSED WORK MAY ALSO INDIRECTLY CONSTRAIN THE COMPOSITION OF TITAN'S HYDROCARBON RAIN (E.G., DETERMINING WHAT METHANEETHANE MIXTURES CAN FREEZE ON TITAN) AND PROVIDING IMPROVE CHARACTERIZATION OF THE THERMODYNAMIC PROPERTIES OF METHANE-ETHANE MIXTURES, IN TURN CONSTRAINING MODELS OF THE COMPOSITION OF TITAN'S RAIN (E.G., THE WORKS OF TOKANO AND GRAVES). OUR LAB RESULTS WILL ALSO DIRECTLY TEST THE IDEA THAT HYDROCARBON ICES CAN INCORPORATE SUFFICIENT POROSITY THROUGH NITROGEN EXSOLUTION TO FLOAT IN TITAN'S SEAS (E.G., HOFGARTNER AND LUNINE, 2013, ICARUS 223) AND MIGHT EXPLAIN TITAN'S RECENT "MAGIC ISLANDS" (HOFGARTNER ET AL., 2014, NATURE GEOSCI. 7). OUR PROPOSED INVESTIGATION IS DIRECTLY RESPONSIVE TO THE PRIMARY GOAL OF THE CASSINI DATA ANALYSIS AND PARTICIPATING SCIENTIST PROGRAM TO ENHANCE THE SCIENTIFIC RETURN OF THE CASSINI MISSION BY BROADENING THE SCIENTIFIC PARTICIPATION IN THE ANALYSIS AND INTERPRETATION OF THE DATA RETURNED BY THE MISSION. OUR WORK WILL RESULT IN BETTER UNDERSTANDING OF THE COMPOSITION OF THE HYDROCARBONS THAT RAIN ONTO TITAN'S SURFACE, AND HOW THAT RAIN DIFFERS IN COMPOSITION FROM THE LAKES AND SEAS. THIS WORK IS RESPONSIVE TO TWO SPECIFIC TASKS RELEVANT TO CDAPS: "UTILIZING DATA OBTAINED BY THE CASSINI AND HUYGENS SPACECRAFT" AND "LABORATORY STUDIES THAT WOULD IGNIFICANTLY FACILITATE THE INTERPRETATION OF DATA FROM THE [CASSINI] MISSION". Funding Only Action ($3k) 11/15/22 Not listed CASSINI IMAGING SCIENCE SUBSYSTEM (ISS) OBSERVATIONS HAVE REVEALED WIDESPREAD DARKENING OF TITAN'S SURFACE BELIEVED TO BE THE RESULT OF RAINFALL FIRST IN 2005 NEAR TITAN'S SOUTH POLE (TURTLE ET AL. 2009 GRL 36) AND LATER IN 2009 IN TITAN'S TROPICS (TURTLE ET AL. 2011 SCIENCE 331). COMBINED CASSINI ISS AND VISUAL AND INFRARED MAPPING SPECTROMETER (VIMS) OBSERVATIONS REVEALED THAT FOLLOWING THIS DARKENING THE ALBEDO OF THE PUTATIVE WETTED SURFACES INCREASED BEYOND EVEN THEIR ORIGINAL ALBEDO (BARNES ET AL. 2013 PLANET. SCI. 2 SODERBLOM ET AL. 2014 DPS). IN THE TROPICS EVENT THE BRIGHTNESS THEN SLOWLY FADED TO A PRE-RAIN BRIGHTNESS OVER 10 MONTHS (BARNES ET AL. 2013) WHILE THE BRIGHTENED SURFACE IN THE SOUTH POLAR CASE WAS STILL BRIGHT COMPARED TO ITS SURROUNDING FOUR YEARS AFTER THE INITIAL RAIN EVENT AND MORE THAN 2 YEARS AFTER THE INCREASED ALBEDO WAS FIRST OBSERVED (SODERBLOM ET AL. 2014). BASED ON THE TIMESCALE AND MAGNITUDE OF THE ALBEDO CHANGES AND THE CORRELATIONS BETWEEN THE TIMESCALE AND TEMPERATURE (INFERRED FROM LATITUDE) OUR PREFERREDHYPOTHESIS IS THAT HYDROCARBONS PRECIPITATED ONTO TITANS SURFACE FROZE VIA EVAPORATIVE COOLING. WE PROPOSE A THREE-YEAR INVESTIGATION THAT COMBINES DATA ANALYSIS AND LABORATORY SIMULATIONS TO DETERMINE WHETHER METHANE-ETHANEMIXTURES IN EQUILIBRIUM WITH A 1.5 BAR NITROGEN ATMOSPHERE CAN FREEZE ON TITAN'S SURFACE AND IF THE CASSINI OBSERVATIONS ARE CONSISTENT WITH SUCH AN INTERPRETATION. WE HAVE CONDUCTED INITIAL EXPERIMENTS WITH PURE METHANE AND ETHANE (E.G. GAINOR ET AL. 2014 LPSC) DEMONSTRATING THE TECHNIQUES NEEDED FOR THIS WORK. THE RESULTS OF THIS WORK WILL HAVE SIGNIFICANT AND BROAD-REACHING IMPLICATIONS REGARDING TITAN'S GEOLOGY HYDROCARBON CYCLE AND TOTAL HYDROCARBON BUDGET. THAT TITAN'S RAIN MAY FREEZE ON THE SURFACE BEGS THE QUESTION "IF SO WHY DON'T TITAN'S LARGER LAKES AND SEAS FREEZE?" OUR WORK WILL HELP TO UNDERSTAND THE CONDITIONS (E.G. MIXING RATIO) UNDER WHICH METHANE-ETHANE MIXTURES MAY OR MAY NOT FREEZE THUS PROVIDING KEY INFORMATION TO ADDRESS SUCH QUESTIONS. OUR PROPOSED WORK MAY ALSO INDIRECTLY CONSTRAIN THE COMPOSITION OF TITAN'S HYDROCARBON RAIN (E.G. DETERMINING WHAT METHANEETHANE MIXTURES CAN FREEZE ON TITAN) AND PROVIDING IMPROVE CHARACTERIZATION OF THE THERMODYNAMIC PROPERTIES OF METHANE-ETHANEMIXTURES IN TURN CONSTRAINING MODELS OF THE COMPOSITION OF TITAN'S RAIN (E.G. THE WORKS OF TOKANO AND GRAVES). OUR LAB RESULTS WILL ALSO DIRECTLY TEST THE IDEA THAT HYDROCARBON ICES CAN INCORPORATE SUFFICIENT POROSITY THROUGH NITROGEN EXSOLUTION TO FLOAT IN TITAN'S SEAS(E.G. HOFGARTNER AND LUNINE 2013 ICARUS 223) AND MIGHT EXPLAIN TITAN'S RECENT "MAGIC ISLANDS" (HOFGARTNER ET AL. 2014 NATURE GEOSCI. 7). OUR PROPOSED INVESTIGATION IS DIRECTLY RESPONSIVE TO THE PRIMARY GOAL OF THE CASSINI DATA ANALYSIS AND PARTICIPATING SCIENTIST PROGRAM TO ENHANCE THE SCIENTIFIC RETURN OF THE CASSINI MISSION BY BROADENING THE SCIENTIFIC PARTICIPATION IN THE ANALYSIS AND INTERPRETATION OF THE DATA RETURNED BY THE MISSION. OUR WORK WILL RESULT IN BETTER UNDERSTANDING OF THE COMPOSITION OF THE HYDROCARBONS THAT RAIN ONTO TITAN'S SURFACE AND HOW THAT RAIN DIFFERS IN COMPOSITION FROM THE LAKES AND SEAS. THIS WORK IS RESPONSIVE TO TWO SPECIFIC TASKS RELEVANTTO CDAPS: "UTILIZING DATA OBTAINED BY THE CASSINI AND HUYGENS SPACECRAFT" AND "LABORATORY STUDIES THAT WOULD IGNIFICANTLY FACILITATE THE INTERPRETATION OF DATA FROM THE [CASSINI] MISSION". ($3k) 11/15/22 Not listed CASSINI IMAGING SCIENCE SUBSYSTEM (ISS) OBSERVATIONS HAVE REVEALED WIDESPREAD DARKENING OF TITAN'S SURFACE BELIEVED TO BE THE RESULT OF RAINFALL FIRST IN 2005 NEAR TITAN'S SOUTH POLE (TURTLE ET AL. 2009 GRL 36) AND LATER IN 2009 IN TITAN'S TROPICS (TURTLE ET AL. 2011 SCIENCE 331). COMBINED CASSINI ISS AND VISUAL AND INFRARED MAPPING SPECTROMETER (VIMS) OBSERVATIONS REVEALED THAT FOLLOWING THIS DARKENING THE ALBEDO OF THE PUTATIVE WETTED SURFACES INCREASED BEYOND EVEN THEIR ORIGINAL ALBEDO (BARNES ET AL. 2013 PLANET. SCI. 2 SODERBLOM ET AL. 2014 DPS). IN THE TROPICS EVENT THE BRIGHTNESS THEN SLOWLY FADED TO A PRE-RAIN BRIGHTNESS OVER 10 MONTHS (BARNES ET AL. 2013) WHILE THE BRIGHTENED SURFACE IN THE SOUTH POLAR CASE WAS STILL BRIGHT COMPARED TO ITS SURROUNDING FOUR YEARS AFTER THE INITIAL RAIN EVENT AND MORE THAN 2 YEARS AFTER THE INCREASED ALBEDO WAS FIRST OBSERVED (SODERBLOM ET AL. 2014). BASED ON THE TIMESCALE AND MAGNITUDE OF THE ALBEDO CHANGES AND THE CORRELATIONS BETWEEN THE TIMESCALE AND TEMPERATURE (INFERRED FROM LATITUDE) OUR PREFERREDHYPOTHESIS IS THAT HYDROCARBONS PRECIPITATED ONTO TITANS SURFACE FROZE VIA EVAPORATIVE COOLING. WE PROPOSE A THREE-YEAR INVESTIGATION THAT COMBINES DATA ANALYSIS AND LABORATORY SIMULATIONS TO DETERMINE WHETHER METHANE-ETHANEMIXTURES IN EQUILIBRIUM WITH A 1.5 BAR NITROGEN ATMOSPHERE CAN FREEZE ON TITAN'S SURFACE AND IF THE CASSINI OBSERVATIONS ARE CONSISTENT WITH SUCH AN INTERPRETATION. WE HAVE CONDUCTED INITIAL EXPERIMENTS WITH PURE METHANE AND ETHANE (E.G. GAINOR ET AL. 2014 LPSC) DEMONSTRATING THE TECHNIQUES NEEDED FOR THIS WORK. THE RESULTS OF THIS WORK WILL HAVE SIGNIFICANT AND BROAD-REACHING IMPLICATIONS REGARDING TITAN'S GEOLOGY HYDROCARBON CYCLE AND TOTAL HYDROCARBON BUDGET. THAT TITAN'S RAIN MAY FREEZE ON THE SURFACE BEGS THE QUESTION "IF SO WHY DON'T TITAN'S LARGER LAKES AND SEAS FREEZE?" OUR WORK WILL HELP TO UNDERSTAND THE CONDITIONS (E.G. MIXING RATIO) UNDER WHICH METHANE-ETHANE MIXTURES MAY OR MAY NOT FREEZE THUS PROVIDING KEY INFORMATION TO ADDRESS SUCH QUESTIONS. OUR PROPOSED WORK MAY ALSO INDIRECTLY CONSTRAIN THE COMPOSITION OF TITAN'S HYDROCARBON RAIN (E.G. DETERMINING WHAT METHANEETHANE MIXTURES CAN FREEZE ON TITAN) AND PROVIDING IMPROVE CHARACTERIZATION OF THE THERMODYNAMIC PROPERTIES OF METHANE-ETHANEMIXTURES IN TURN CONSTRAINING MODELS OF THE COMPOSITION OF TITAN'S RAIN (E.G. THE WORKS OF TOKANO AND GRAVES). OUR LAB RESULTS WILL ALSO DIRECTLY TEST THE IDEA THAT HYDROCARBON ICES CAN INCORPORATE SUFFICIENT POROSITY THROUGH NITROGEN EXSOLUTION TO FLOAT IN TITAN'S SEAS(E.G. HOFGARTNER AND LUNINE 2013 ICARUS 223) AND MIGHT EXPLAIN TITAN'S RECENT "MAGIC ISLANDS" (HOFGARTNER ET AL. 2014 NATURE GEOSCI. 7). OUR PROPOSED INVESTIGATION IS DIRECTLY RESPONSIVE TO THE PRIMARY GOAL OF THE CASSINI DATA ANALYSIS AND PARTICIPATING SCIENTIST PROGRAM TO ENHANCE THE SCIENTIFIC RETURN OF THE CASSINI MISSION BY BROADENING THE SCIENTIFIC PARTICIPATION IN THE ANALYSIS AND INTERPRETATION OF THE DATA RETURNED BY THE MISSION. OUR WORK WILL RESULT IN BETTER UNDERSTANDING OF THE COMPOSITION OF THE HYDROCARBONS THAT RAIN ONTO TITAN'S SURFACE AND HOW THAT RAIN DIFFERS IN COMPOSITION FROM THE LAKES AND SEAS. THIS WORK IS RESPONSIVE TO TWO SPECIFIC TASKS RELEVANTTO CDAPS: "UTILIZING DATA OBTAINED BY THE CASSINI AND HUYGENS SPACECRAFT" AND "LABORATORY STUDIES THAT WOULD IGNIFICANTLY FACILITATE THE INTERPRETATION OF DATA FROM THE [CASSINI] MISSION". $0 6/3/21 9 CASSINI IMAGING SCIENCE SUBSYSTEM (ISS) OBSERVATIONS HAVE REVEALED WIDESPREAD DARKENING OF TITAN'S SURFACE BELIEVED TO BE THE RESULT OF RAINFALL, FIRST IN 2005 NEAR TITAN'S SOUTH POLE (TURTLE ET AL., 2009, GRL 36), AND LATER IN 2009 IN TITAN'S TROPICS (TURTLE ET AL., 2011, SCIENCE 331). COMBINED CASSINI ISS AND VISUAL AND INFRARED MAPPING SPECTROMETER (VIMS) OBSERVATIONS REVEALED THAT, FOLLOWING THIS DARKENING, THE ALBEDO OF THE PUTATIVE WETTED SURFACES INCREASED, BEYOND EVEN THEIR ORIGINAL ALBEDO (BARNES ET AL., 2013, PLANET. SCI. 2 SODERBLOM ET AL., 2014, DPS). IN THE TROPICS EVENT, THE BRIGHTNESS THEN SLOWLY FADED TO A PRE-RAIN BRIGHTNESS OVER 10 MONTHS (BARNES ET AL., 2013), WHILE THE BRIGHTENED SURFACE IN THE SOUTH POLAR CASE WAS STILL BRIGHT COMPARED TO ITS SURROUNDING FOUR YEARS AFTER THE INITIAL RAIN EVENT, AND MORE THAN 2 YEARS AFTER THE INCREASED ALBEDO WAS FIRST OBSERVED (SODERBLOM ET AL., 2014). BASED ON THE TIMESCALE AND MAGNITUDE OF THE ALBEDO CHANGES, AND THE CORRELATIONS BETWEEN THE TIMESCALE AND TEMPERATURE (INFERRED FROM LATITUDE), OUR PREFERRED HYPOTHESIS IS THAT HYDROCARBONS PRECIPITATED ONTO TITANS SURFACE FROZE VIA EVAPORATIVE COOLING. WE PROPOSE A THREE-YEAR INVESTIGATION THAT COMBINES DATA ANALYSIS AND LABORATORY SIMULATIONS TO DETERMINE WHETHER METHANE-ETHANE MIXTURES, IN EQUILIBRIUM WITH A 1.5 BAR NITROGEN ATMOSPHERE, CAN FREEZE ON TITAN'S SURFACE, AND IF THE CASSINI OBSERVATIONS ARE CONSISTENT WITH SUCH AN INTERPRETATION. WE HAVE CONDUCTED INITIAL EXPERIMENTS WITH PURE METHANE AND ETHANE (E.G., GAINOR ET AL., 2014, LPSC), DEMONSTRATING THE TECHNIQUES NEEDED FOR THIS WORK. THE RESULTS OF THIS WORK WILL HAVE SIGNIFICANT AND BROAD-REACHING IMPLICATIONS REGARDING TITAN'S GEOLOGY, HYDROCARBON CYCLE, AND TOTAL HYDROCARBON BUDGET. THAT TITAN'S RAIN MAY FREEZE ON THE SURFACE BEGS THE QUESTION, "IF SO, WHY DON'T TITAN'S LARGER LAKES AND SEAS FREEZE?" OUR WORK WILL HELP TO UNDERSTAND THE CONDITIONS (E.G., MIXING RATIO) UNDER WHICH METHANE-ETHANE MIXTURES MAY OR MAY NOT FREEZE, THUS PROVIDING KEY INFORMATION TO ADDRESS SUCH QUESTIONS. OUR PROPOSED WORK MAY ALSO INDIRECTLY CONSTRAIN THE COMPOSITION OF TITAN'S HYDROCARBON RAIN (E.G., DETERMINING WHAT METHANEETHANE MIXTURES CAN FREEZE ON TITAN) AND PROVIDING IMPROVE CHARACTERIZATION OF THE THERMODYNAMIC PROPERTIES OF METHANE-ETHANE MIXTURES, IN TURN CONSTRAINING MODELS OF THE COMPOSITION OF TITAN'S RAIN (E.G., THE WORKS OF TOKANO AND GRAVES). OUR LAB RESULTS WILL ALSO DIRECTLY TEST THE IDEA THAT HYDROCARBON ICES CAN INCORPORATE SUFFICIENT POROSITY THROUGH NITROGEN EXSOLUTION TO FLOAT IN TITAN'S SEAS (E.G., HOFGARTNER AND LUNINE, 2013, ICARUS 223) AND MIGHT EXPLAIN TITAN'S RECENT "MAGIC ISLANDS" (HOFGARTNER ET AL., 2014, NATURE GEOSCI. 7). OUR PROPOSED INVESTIGATION IS DIRECTLY RESPONSIVE TO THE PRIMARY GOAL OF THE CASSINI DATA ANALYSIS AND PARTICIPATING SCIENTIST PROGRAM TO ENHANCE THE SCIENTIFIC RETURN OF THE CASSINI MISSION BY BROADENING THE SCIENTIFIC PARTICIPATION IN THE ANALYSIS AND INTERPRETATION OF THE DATA RETURNED BY THE MISSION. OUR WORK WILL RESULT IN BETTER UNDERSTANDING OF THE COMPOSITION OF THE HYDROCARBONS THAT RAIN ONTO TITAN'S SURFACE, AND HOW THAT RAIN DIFFERS IN COMPOSITION FROM THE LAKES AND SEAS. THIS WORK IS RESPONSIVE TO TWO SPECIFIC TASKS RELEVANT TO CDAPS: "UTILIZING DATA OBTAINED BY THE CASSINI AND HUYGENS SPACECRAFT" AND "LABORATORY STUDIES THAT WOULD IGNIFICANTLY FACILITATE THE INTERPRETATION OF DATA FROM THE [CASSINI] MISSION". Other Administrative Action $0 6/3/21 8 CASSINI IMAGING SCIENCE SUBSYSTEM (ISS) OBSERVATIONS HAVE REVEALED WIDESPREAD DARKENING OF TITAN'S SURFACE BELIEVED TO BE THE RESULT OF RAINFALL, FIRST IN 2005 NEAR TITAN'S SOUTH POLE (TURTLE ET AL., 2009, GRL 36), AND LATER IN 2009 IN TITAN'S TROPICS (TURTLE ET AL., 2011, SCIENCE 331). COMBINED CASSINI ISS AND VISUAL AND INFRARED MAPPING SPECTROMETER (VIMS) OBSERVATIONS REVEALED THAT, FOLLOWING THIS DARKENING, THE ALBEDO OF THE PUTATIVE WETTED SURFACES INCREASED, BEYOND EVEN THEIR ORIGINAL ALBEDO (BARNES ET AL., 2013, PLANET. SCI. 2 SODERBLOM ET AL., 2014, DPS). IN THE TROPICS EVENT, THE BRIGHTNESS THEN SLOWLY FADED TO A PRE-RAIN BRIGHTNESS OVER 10 MONTHS (BARNES ET AL., 2013), WHILE THE BRIGHTENED SURFACE IN THE SOUTH POLAR CASE WAS STILL BRIGHT COMPARED TO ITS SURROUNDING FOUR YEARS AFTER THE INITIAL RAIN EVENT, AND MORE THAN 2 YEARS AFTER THE INCREASED ALBEDO WAS FIRST OBSERVED (SODERBLOM ET AL., 2014). BASED ON THE TIMESCALE AND MAGNITUDE OF THE ALBEDO CHANGES, AND THE CORRELATIONS BETWEEN THE TIMESCALE AND TEMPERATURE (INFERRED FROM LATITUDE), OUR PREFERRED HYPOTHESIS IS THAT HYDROCARBONS PRECIPITATED ONTO TITANS SURFACE FROZE VIA EVAPORATIVE COOLING. WE PROPOSE A THREE-YEAR INVESTIGATION THAT COMBINES DATA ANALYSIS AND LABORATORY SIMULATIONS TO DETERMINE WHETHER METHANE-ETHANE MIXTURES, IN EQUILIBRIUM WITH A 1.5 BAR NITROGEN ATMOSPHERE, CAN FREEZE ON TITAN'S SURFACE, AND IF THE CASSINI OBSERVATIONS ARE CONSISTENT WITH SUCH AN INTERPRETATION. WE HAVE CONDUCTED INITIAL EXPERIMENTS WITH PURE METHANE AND ETHANE (E.G., GAINOR ET AL., 2014, LPSC), DEMONSTRATING THE TECHNIQUES NEEDED FOR THIS WORK. THE RESULTS OF THIS WORK WILL HAVE SIGNIFICANT AND BROAD-REACHING IMPLICATIONS REGARDING TITAN'S GEOLOGY, HYDROCARBON CYCLE, AND TOTAL HYDROCARBON BUDGET. THAT TITAN'S RAIN MAY FREEZE ON THE SURFACE BEGS THE QUESTION, "IF SO, WHY DON'T TITAN'S LARGER LAKES AND SEAS FREEZE?" OUR WORK WILL HELP TO UNDERSTAND THE CONDITIONS (E.G., MIXING RATIO) UNDER WHICH METHANE-ETHANE MIXTURES MAY OR MAY NOT FREEZE, THUS PROVIDING KEY INFORMATION TO ADDRESS SUCH QUESTIONS. OUR PROPOSED WORK MAY ALSO INDIRECTLY CONSTRAIN THE COMPOSITION OF TITAN'S HYDROCARBON RAIN (E.G., DETERMINING WHAT METHANEETHANE MIXTURES CAN FREEZE ON TITAN) AND PROVIDING IMPROVE CHARACTERIZATION OF THE THERMODYNAMIC PROPERTIES OF METHANE-ETHANE MIXTURES, IN TURN CONSTRAINING MODELS OF THE COMPOSITION OF TITAN'S RAIN (E.G., THE WORKS OF TOKANO AND GRAVES). OUR LAB RESULTS WILL ALSO DIRECTLY TEST THE IDEA THAT HYDROCARBON ICES CAN INCORPORATE SUFFICIENT POROSITY THROUGH NITROGEN EXSOLUTION TO FLOAT IN TITAN'S SEAS (E.G., HOFGARTNER AND LUNINE, 2013, ICARUS 223) AND MIGHT EXPLAIN TITAN'S RECENT "MAGIC ISLANDS" (HOFGARTNER ET AL., 2014, NATURE GEOSCI. 7). OUR PROPOSED INVESTIGATION IS DIRECTLY RESPONSIVE TO THE PRIMARY GOAL OF THE CASSINI DATA ANALYSIS AND PARTICIPATING SCIENTIST PROGRAM TO ENHANCE THE SCIENTIFIC RETURN OF THE CASSINI MISSION BY BROADENING THE SCIENTIFIC PARTICIPATION IN THE ANALYSIS AND INTERPRETATION OF THE DATA RETURNED BY THE MISSION. OUR WORK WILL RESULT IN BETTER UNDERSTANDING OF THE COMPOSITION OF THE HYDROCARBONS THAT RAIN ONTO TITAN'S SURFACE, AND HOW THAT RAIN DIFFERS IN COMPOSITION FROM THE LAKES AND SEAS. THIS WORK IS RESPONSIVE TO TWO SPECIFIC TASKS RELEVANT TO CDAPS: "UTILIZING DATA OBTAINED BY THE CASSINI AND HUYGENS SPACECRAFT" AND "LABORATORY STUDIES THAT WOULD IGNIFICANTLY FACILITATE THE INTERPRETATION OF DATA FROM THE [CASSINI] MISSION". Other Administrative Action $0 5/6/20