HR: 1330h
AN: SM22B-0234    [PDF]
TI: Science and Payload Drivers for the Jupiter Icy Moons Orbiter
AU: * McNutt, R L
EM: ralph_mcnutt@jhuapl.edu
AF: Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 United States
AB: Primary science goals of a mission to the outer three Galilean satellites include the deduction of internal structure and the possible presence of liquid water beneath the ice crusts of these worlds. A liquid-water mantle can provide an explanation of the magnetic characteristics of these moons and also provide a possible site for biological activity, but major unknowns include the possible extent and composition of a sub-surface brine "sea." Using the power re-sources available on the Jupiter Icy Moons Orbiter (JIMO) spacecraft critical data on all of these topics can be re-turned to Earth. A comprehensive payload that can definitely address these goals requires a radar sounder, laser al-timeter, and a suite of fields and particles instruments. An optimized radar sounder for probing beneath the ice should likely be capable of functioning $\sim$50 MHz at as high a power level as consistent with JIMO resources. A laser altimeter will have a larger mass-to-power ratio and worse power efficiency than a radar sounder. Mass is driven by the optical receiver and alignment requirements. Supporting instrumentation including a magnetometer (magnetic field in situ), imager ("geology" and ice structures), and spectrometers ("mineralogy") are obvious candi-dates for JIMO. Even more important is the inclusion of particle instruments that can measure pickup elements and their isotopes present in the in-situ plasma due to sputtering from the surface of the moons. Such trace elements and isotopes are important for understanding surface processes and adducing the materials present in the ice and impli-cations for subsurface biological activity. Knowledge of these trace elements is also important to understanding the context of the sounder observations. A "wish list" payload combining state-of-the-art instrumentation would com-prise 19 instruments with a mass of 644 kg and requiring 712 W of power, exclusive of a radar sounder. Addition of a 1-kW radar sounder could bring the mass and power totals to nominal values $\sim$900 kg and $\sim$3700 W, respectively. To exploit fully such instrumentation, data rates of greater than megabits per second from Jupiter are required, an additional mass and power driver.
DE: 2756 Planetary magnetospheres (5443, 5737, 6030)
DE: 2794 Instruments and techniques
DE: 6218 Jovian satellites
DE: 6297 Instruments and techniques
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting