HR: 1330h
AN: P12A-1054    [PDF]
TI: Radio Science Concepts for Exploring the Interior Structures of Jupiter's Icy Moons
AU: * Asmar, S W
EM: sami.asmar@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr, Pasadena, CA 91109 United States
AU: Anderson, J D
EM: john.d.anderson@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr, Pasadena, CA 91109 United States
AU: Castillo, J C
AF: National Research Council/Jet Propulsion Laboratory, 4800 Oak Grove Dr, Pasadena, CA 91109 United States
AU: Folkner, W M
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr, Pasadena, CA 91109 United States
AU: Konopliv, A S
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr, Pasadena, CA 91109 United States
AU: Marouf, E A
AF: San Jose State University, One Washington Square, San Jose, CA 95192 United States
AU: Rappaport, N J
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr, Pasadena, CA 91109 United States
AU: Schubert, G
AF: University of California, Los Angeles, Earth And Space Sciences, Los Angeles, CA 90095 United States
AU: Spilker, T R
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr, Pasadena, CA 91109 United States
AU: Tyler, G L
AF: Stanford University, Packard Building, Stanford, CA 94305 United States
AU: Watkins, M M
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr, Pasadena, CA 91109 United States
AU: Yoder, C F
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr, Pasadena, CA 91109 United States
AB: A set of concepts are proposed for the Jupiter Icy Moons Orbiter (JIMO) to apply Radio Science tools to investigate the interior structures of the Galilean Satellites and address key questions on their thermal and dynamical evolution. Multi-frequency Doppler tracking and ranging of the orbiter can be used to measure the gravity harmonic coefficients of the satellites as well as their secular and dynamic potential Love numbers. These measurements will confirm the presence of a subsurface ocean and constrain the oceanic density. Under the assumption of hydrostatic equilibrium, the core's size and density will be determined. The potential tidal phase lag, a function of the viscosity profile, will be determined or limited for each body. Altimetry data produce local topography and topographic harmonic coefficients as well as the topographic Love number. Combining the gravity and topography data will determine the mean as well as the spatial variations of the crustal thickness and produce a model of the cryospheric structure. This knowledge leads to understanding the mechanisms of topographic support or compensation and any large-scale geomorphological features related to the interior. Accelerometers measure the non-gravitational forces acting on the spacecraft, a typical systematic noise type in the gravity data and, thus, improve the accuracy of the measurement. Gradiometers improve the resolution of the data by providing higher spatial resolution in the gravity field and its correlation with the topography. The resulting information will be crucial to establishing the link between surface and internal dynamics leading to identifying the terrain with easiest ocean access and to understanding the origin of the chaotic terrains and ridges. Time observations of surface features enable an examination of the difference between the obliquity and inclination which, when combined with the gravity data, provide a measurement of the moments of inertia. High stability coherent transponders at X- and Ka-bands feeding high power transmitters will likely be the nucleus of the orbiter's telecommunication system. Augmentation will include a stable clock, accelerometer(s) and gradiometer(s). Incorporating an altimeter among the suite of JIMO instruments is important. The altitude of the spacecraft, the number of orbits and system noise limit the degree and order of each gravitational field. Simulation show that Europa's gravitational Love number can be determined to better than 0.002 (one-sigma) far exceeding the value needed to infer the presence of an ocean. A capable Radio Science investigation with JIMO will lead to detailed knowledge of the interior structure of the Galilean Satellites. Altimetry, accelerometery, gradiometry as well as surface feature tracking will supplement the investigation to further understand the dynamical evolution. Atmospheres and surfaces of the satellites will also be studied via the Radio Science instrument.
DE: 0920 Gravity methods
DE: 0933 Remote sensing
DE: 1200 GEODESY AND GRAVITY
DE: 5400 PLANETOLOGY: SOLID SURFACE PLANETS
DE: 6900 RADIO SCIENCE
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting