From: IN%"kent.tobiska@jpl.nasa.gov" "W. Kent Tobiska" 26-JUL-1999 20:58:28.16 Subj: UVS/EUV GMM OPG draft objectives Date: Mon, 26 Jul 1999 14:00:22 -0700 From: "W. Kent Tobiska" Subject: UVS/EUV GMM OPG draft objectives To: Kathryn Schimmels Cc: kent.tobiska@jpl.nasa.gov, Amanda Hendrix , "Ian A.F. Stewart" Io Phase: Orbits I24, I25, and I27 enable the UVS and EUV to concentrate upon Io science related to studies of: - satellite surface properties (24IUSURFAC01, 24IUSURFAC02, 24IUSURFAC03, 25IUSURFAC01, 25IUSURFAC02, 27IUSURFAC01); - satellite atmosphere characterization (24IUATMOS_01, 24IUATMOS_02, 25IUATMOS_01, 25IUATMOS_02, 27IUATMOS_01); - satellite aurora (24IUECLIPS01, 25IUECLIPS01, 27IUECLIPS01); and - Io torus morphology (24TV24NANS01, 24TU24NANS01, 24TU24NANS02, 25TV24NANS01, 25TU25NANS01, 25TU25NANS02, 27TVNANSA_01, 27TUNANSA_01). Orbit E26 is limited solely to EUV observations of the Io torus (26TVMANSA_01). The six (6) satellite surface property observations are primarily full spectral studies in the FUV to MUV to observe species absorption and excitation processes as well as scattering properties of the surface. These studies will complement previous work in the prime and GEM missions and will be studied in the context of other instruments observations (NIMS, SSI, and PPR). The five (5) satellite atmosphere characterization studies also use full spectral scans in the FUV and MUV to observe Io atmospheric hydrogen, sulphur, and oxygen as it is released to space. The three (3) satellite aurora observations are all made when Io is in eclipse and, where possible, will be compared to SSI images of Io in eclipse. In particular, the removal of scattered sunlight for these FUV-MUV-NUV observations will potentially reveal new information about Jupiter's magnetospheric and energetic interactions with the Io atmosphere and surface. The nine (9) Io torus observations with the EUV and UVS continue the morphological study of the Io torus and provide the basis for a long term comparison between prime mission and GMM datasets over 4 years as well as asymmetries between dawn (prime mission) and dusk (GMM) torus ansae. There are four (4) additional observations of Europa by the UVS instrument in this phase (25EUNPOLE_01, 25EUSUBJUP01, 25EUEQUATR01, 25EUGLOBAL01). These four observations are ridealong studies with the NIMS instrument using full spectrum MUV data to continue studies of unique surface features, their scattering properties, surface composition, and formation processes. Cassini Phase: Orbits G28 and G29 provide a duet of unique opportunities to study the Jovian system close-in while Cassini observes the system from afar. The UVS and EUV instruments will study: - satellite surface properties (28GUSURFAC01, 28GUSURFAC02, 28IUSURFAC01, 29GUSURFAC01); - satellite and Jupiter atmosphere characterization (28GUBRTLMB01, 28JUCORONA01); - satellite and Jupiter aurora (28IUAURORA01, 28JUAUR_SW01, 29EUECLIPS01, 29EUECLIPS02, 29IUAURORA01, 29GUAURORA01, 29GUAURORA02, 29JUAUR_SW01, 29JUAURZON01); - Io torus morphology (28TVNANSA_01, 28TUNANSA_01, 29TUMIDPRO01); and - conduct calibration activities (28JUSTRCAL01, 28HUEUXCAL01, 28HVEUXCAL01). The four (4) satellite surface property observations are primarily full spectral studies in the FUV to MUV to observe species absorption and excitation processes as well as scattering properties of the surface. These studies will complement previous work in the prime and GEM missions and will be studied in the context of other instruments observations (NIMS, SSI, and PPR). The two (2) satellite atmosphere characterization studies will use full spectral scans and miniscans in the FUV-NUV to observe Ganymede's and Jupiter's atmospheric hydrogen and oxygen as it is released to space, including Jupiter's extended H corona. The nine (9) satellite and Jupiter aurora observations are made under a variety of conditions such as when Io and Ganymede are in eclipse and, where possible, will be compared to SSI eclipse images. In particular, the removal of scattered sunlight for these FUV-MUV-NUV observations will potentially reveal new information about Jupiter's magnetospheric and energetic interactions with the satellites' atmosphere and surface. In addition, the JUAUR_SW01 observations will study the solar wind perturbation to the Jovian magnetosphere (aurora) over a full solar rotation in coincidence with Cassini solar wind observations while the JUAURZON recorded observation will characterize newly hypothesized flares in the Jovian auroral region at high time resolution. The three (3) Io torus observations with the EUV and UVS continue the morphological study of the Io torus and provide the basis for a long term comparison between prime mission and GMM datasets over 4 years as well as asymmetries between dawn (prime mission) and dusk (GMM) torus ansae. Finally, the instrument team will perform an end-of-mission star and cross calibration between the two instruments.