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MOTIVATION: WHILE THE NITROGEN-RICH HIGH PRESSURE ATMOSPHERE AT TITAN HAS SOME SIMILARITIES TO THE TERRESTRIAL ATMOSPHERE THERE IS A VERY SIGNIFICANT DIFFERENCE: THE ATMOSPHERIC ELECTRICAL CONDUCTIVITY. SPECIFICALLY MODELING OF TITAN S NEAR-SURFACE ATMOSPHERE INDICATES THAT THE ELECTRON CONDUCTIVITY GREATLY EXCEEDS THE POSITIVE ION CONDUCTIVITY POSSIBLY BY MANY ORDERS OF MAGNITUDE (MOLINA-CUBEROS ADV SPACE RES 28 1511 2001). THIS UNUSUALLY HIGH ELECTRICAL CONDUCTIVITY AND CHARGE BIASING DECREASES ELECTRICAL CHARGE DISSIPATION TIMES QUICKLY REMOVING CHARGE FROM SYSTEMS SUCH AS ELECTRIC STORMS AND LANDED ROBOTIC EQUIPMENT. HOWEVER THE CONDUCTIVITY IMBALANCE COULD POTENTIALLY MAKE ANY NEGATIVELY CHARGED OBJECT RETAIN ITS CHARGE FAR LONGER THAN A POSITIVELY CHARGED OBJECT AFFECTING LANDERS AND OTHER PROBES. OBJECTIVES: WE WILL PERFORM A VALIDATING LABORATORY STUDY TO UNDERSTAND THE IMPACT THAT THE UNUSUAL ELECTRICAL CONDUCTIVITY HAS ON THE ATMOSPHERIC ELECTRICAL ENVIRONMENT AT TITAN. WE WILL PERFORM A LABORATORY TEST OF THE BREAKDOWN OF AN ELECTRON-RICH AEROSOL-FILLED N2 GAS USING A CHAMBER SPECIFICALLY DESIGNED TO MIMIC TITAN S PRESSURE AND TEMPERATURE. FLECKS OF ORGANIC MATERIAL (THOLINS) FORM EXTENSIVE DUNES ON TITAN. THIS LOW DENSITY MATERIAL SHOULD BECOME TRIBOCHARGED DURING AEOLIAN TRANSPORT. WE WILL ALSO ASSESS THIS MIXING DUST AS A TRIBOELECTRIC GENERATOR VIA A WIND TUNNEL TEST IN THE AMES PLANETARY AEOLIAN LABORATORY. GIVEN THE MODEL AND LAB WORK WE WILL APPLY RESULTS TO THE CASE FOR LIGHTNING STORMS AT TITAN. THE CASSINI RADIO AND PLASMA WAVE SCIENCE (RPWS) INSTRUMENT HAS NOT DETECTED RADIO EVIDENCE OF LIGHTNING (FISCHER ET AL. 2007 DOI:10.1029/2007GL031668)) EVEN AFTER OVER 120 PASSES BY THE MOON WITH A VERY SENSITIVE RADIO SYSTEM. IN 2011 WE DEVELOPED A MODEL THAT SUGGESTED THE ANOMALOUSLY HIGH CONDUCTIVITY AT TITAN ACTED TO 'SHORT OUT' THE STORM S CHARGING CENTERS. WE WILL VALIDATE AND ADVANCE THIS MODEL IN THIS NEW STUDY HEREIN.

$175,900FY2020National Aeronautics and Space AdministrationNASA

Seti Institute, Mountain View CA

Investigators

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MOTIVATION: WHILE THE NITROGEN-RICH HIGH PRESSURE ATMOSPHERE AT TITAN HAS SOME SIMILARITIES TO THE TERRESTRIAL ATMOSPHERE THERE IS A VERY SIGNIFICANT DIFFERENCE: THE ATMOSPHERIC ELECTRICAL CONDUCTIVITY. SPECIFICALLY MODELING OF TITAN S NEAR-SURFACE ATMOSPHERE INDICATES THAT THE ELECTRON CONDUCTIVITY GREATLY EXCEEDS THE POSITIVE ION CONDUCTIVITY POSSIBLY BY MANY ORDERS OF MAGNITUDE (MOLINA-CUBEROS ADV SPACE RES 28 1511 2001). THIS UNUSUALLY HIGH ELECTRICAL CONDUCTIVITY AND CHARGE BIASING DECREASES ELECTRICAL CHARGE DISSIPATION TIMES QUICKLY REMOVING CHARGE FROM SYSTEMS SUCH AS ELECTRIC STORMS AND LANDED ROBOTIC EQUIPMENT. HOWEVER THE CONDUCTIVITY IMBALANCE COULD POTENTIALLY MAKE ANY NEGATIVELY CHARGED OBJECT RETAIN ITS CHARGE FAR LONGER THAN A POSITIVELY CHARGED OBJECT AFFECTING LANDERS AND OTHER PROBES. OBJECTIVES: WE WILL PERFORM A VALIDATING LABORATORY STUDY TO UNDERSTAND THE IMPACT THAT THE UNUSUAL ELECTRICAL CONDUCTIVITY HAS ON THE ATMOSPHERIC ELECTRICAL ENVIRONMENT AT TITAN. WE WILL PERFORM A LABORATORY TEST OF THE BREAKDOWN OF AN ELECTRON-RICH AEROSOL-FILLED N2 GAS USING A CHAMBER SPECIFICALLY DESIGNED TO MIMIC TITAN S PRESSURE AND TEMPERATURE. FLECKS OF ORGANIC MATERIAL (THOLINS) FORM EXTENSIVE DUNES ON TITAN. THIS LOW DENSITY MATERIAL SHOULD BECOME TRIBOCHARGED DURING AEOLIAN TRANSPORT. WE WILL ALSO ASSESS THIS MIXING DUST AS A TRIBOELECTRIC GENERATOR VIA A WIND TUNNEL TEST IN THE AMES PLANETARY AEOLIAN LABORATORY. GIVEN THE MODEL AND LAB WORK WE WILL APPLY RESULTS TO THE CASE FOR LIGHTNING STORMS AT TITAN. THE CASSINI RADIO AND PLASMA WAVE SCIENCE (RPWS) INSTRUMENT HAS NOT DETECTED RADIO EVIDENCE OF LIGHTNING (FISCHER ET AL. 2007 DOI:10.1029/2007GL031668)) EVEN AFTER OVER 120 PASSES BY THE MOON WITH A VERY SENSITIVE RADIO SYSTEM. IN 2011 WE DEVELOPED A MODEL THAT SUGGESTED THE ANOMALOUSLY HIGH CONDUCTIVITY AT TITAN ACTED TO 'SHORT OUT' THE STORM S CHARGING CENTERS. WE WILL VALIDATE AND ADVANCE THIS MODEL IN THIS NEW STUDY HEREIN. · GrantIndex