WE PROPOSE TO INVESTIGATE THE PROCESS RESPONSIBLE FOR THE UNEXPLAINED HEATING OF THE OUTER PLANET UPPER ATMOSPHERES BY MONITORING SEASON-LENGTH CHANGES OF URANUS' NEAR- AND MID-IR EMISSION-LINE SPECTRA THAT ARISE LARGELY FROM THE THERMOSPHERE. FOR ANY OF THE OUTER PLANETS THE ABSORBED EUV INSOLATION FALLS SHORT BY MORE THAN A FACTOR OF 3 IN EXPLAINING THE UPPER ATMOSPHERIC TEMPERATURE; AND ALTERNATIVE HEAT SOURCES PROPOSED HAVE NOT BEEN ABLE TO MAKE UP THE DIFFERENCE. AMONG THE OUTER PLANETS URANUS IS ATTRACTIVE FOR SUCH A STUDY BECAUSE OF ITS STEEP OBLIQUITY AND RESULTING STRONG SEASONAL FORCING ITS MINIMAL INTERNAL HEAT SOURCE THAT MAXIMIZES THE CONTRAST OF IR SEASONAL PHENOMENA AND A SEASON-LONG OBSERVATIONAL RECORD OF GLOBAL H3+ AND TO A LESSER EXTENT H2 EMISSION SPECTRA. THE H3+ OBSERVATIONS HAVE SHOWN A LONG-TERM DOWNTREND IN THE THERMOSPHERIC/IONOSPHERIC TEMPERATURE OF 8 DEG K/YR THAT HAS EXTENDED A THIRD OF A SEASON BEYOND THE 2007 EQUINOX WHEN THE GLOBAL HEATING RATE WAS A MINIMUM. SINCE EQUINOX THE INSOLATION SHOULD BE FORCING A TREND REVERSAL IF THE DECLINE IS SEASONAL. ALTERNATIVELY A CONTINUED DROP IN TEMPERATURE MIGHT INDICATE THAT THE EXCESS HEATING IS A FUNCTION OF ORBITAL CHANGES IN GEOMETRY; E.G. OF URANUS' DAILY MEAN MAGNETOSPHERIC INCLINATION TO THE SOLAR WIND. THE PHASE LAG DEPENDS ON A COMPETITION BETWEEN THE KNOWN RADIATION AND THE UNKNOWN BUT DOMINATING DYNAMICS IN REHEATING THE THERMOSPHERE; AND IS THUS A DIAGNOSTIC CONSTRAINT ON THE OPERATIVE DYNAMICAL PROCESS. THE 2014 - 2016 APPARITIONS INDICATE MARGINAL WARMING OF THE URANIAN IONOSPHERE SUGGESTING THAT A POSSIBLE TREND REVERSAL MAY BE IN PROGRESS. THE TREND REVERSAL FOR H2 EMISSION IS EXPECTED TO OCCUR LATER SINCE IT ORIGINATES EFFECTIVELY DEEPER WHERE THE RADIATIVE TIME CONSTANT IS LONGER. CONTINUING MONITORING OF URANUS' H3+ AND H2 EMISSION SPECTRA ARE PROPOSED TO CHARACTERIZE THEIR SEASONAL TREND REVERSALS. OBJECTIVES ARE THE POST-EQUINOCTIAL LAGS OF THE MINIMA IN THE H3+ AND H2 TEMPERATURES DURATION OF THE MINIMA AND THE RECOVERY TEMPERATURE SLOPE. THESE ARE EXPECTED TO PLACE CONSTRAINTS ON THE DYNAMICAL PROCESS DOMINATING THE HEATING OF THE THERMOSPHERE. OUR GOALS ARE 1) TO CHARACTERIZE A CRITICAL SEASONAL TREND REVERSAL EXPECTED IN URANUS THERMOSPHERIC/IONOSPHERIC RO-VIB H3+ TEMPERATURE WHICH HAS BEEN IN A DOWNTREND SINCE FIRST OBSERVED IN 1992; 2) COMPARE AND CONTRAST THE PAST AND ONGOING TREND OF URANUS THERMOSPHERIC RO-VIB H2 TEMPERATURE WITH THAT FOR H3+ WHICH PROBES DEEPER THAN THE HOMOPAUSE-LIMITED H3+; 3) OBTAIN BASELINE POST-MINIMUM MEASUREMENTS TO ESTABLISH THE EPOCH OF THE REVERSAL VIA BACKWARDS EXTRAPOLATION AND FOR COMPARING THE RATE OF RECOVERY WITH THE LONG TERM DOWNTREND AS A CONSTRAINT ON THE SEASONAL HEATING/COOLING PROCESS; 4) PROBE THE LATITUDINAL TEMPERATURE STRUCTURE NEAR THE EPOCH OF TEMPERATURE REVERSAL. THE PROPOSED RESEARCH WOULD SUPPORT THE GOALS AND OBJECTIVES OF THE PLANETARY ASTRONOMY COMPONENT OF SSO BY CONDUCTING NEW GROUND BASED OBSERVATIONS THAT CONTRIBUTE TO UNDERSTANDING OF AN ACTIVE PROCESS IN THE THERMOSPHERES AND IONOSPHERES OF THE OUTER PLANETS EXPLICITLY FOR URANUS BUT POTENTIALLY FOR ALL. THE PROPOSED OBSERVATIONS WOULD INVESTIGATE THE UNKNOWN PROCESS FOR THE DOMINANT SOURCE OF HEATING IN OUTER PLANET THERMOSPHERES WHICH CONTROLS THEIR ENERGY BALANCE AND STRUCTURE AND HOW THEY RESPOND TO SEASONAL AND SOLAR CYCLE CHANGES. THESE OBSERVATIONS WOULD PROVIDE A SPECTRAL RESOLUTION THAT CURRENT SPACECRAFT LACK. THIS RESEARCH WOULD PLACE THE VOYAGER UVS RESULTS IN A GREATER CONTEXT. SSO IS BEST BECAUSE GROUND-BASED IR SOLAR SYSTEM ASTRONOMICAL OBSERVATIONS/MONITORING ARE REQUIRED FOR THE SUCCESSFUL PURSUIT OF THIS INVESTIGATION.