HR: 1340h
AN: P23B-1367    [Abstracts]
TI: The Gravity Science Analysis of Cassini Flybys T11 and T22 and Future Work
AU: * Rappaport, N J
EM: Nicole.J.Rappaport@jpl.nasa.gov
AF: Jet Propulsion Laboratory California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AU: Iess, L
EM: luciano.iess@uniroma1.it
AF: Dipartimento di Ingegneria Aerospaziale ed Astronautica, Universita' di Roma "La Sapienza", Via Eudossiano, 18, Roma, 00184, Italy
AU: Tortora, P
EM: paolo.tortora@unibo.it
AF: DIEM, Universita' di Bologna, Via Fontanelle, 40, Forli, 47100, Italy
AU: Wahr, J
EM: John.Wahr@Colorado.EDU
AF: Department of Physics, University of Colorado, Boulder, CO 80309, United States
AU: Lunine, J I
AF: Lunar and Planetary Laboratory, 1629 E. University Boulevard, Tucson, AZ 85721, United States
AU: Lunine, J I
AF: INAF/IFSI, Via del Fosso del Cavaliere, Roma, 00133, Italy
AU: MacKenzie, R A
EM: Ruaraidh.A.MacKenzie@jpl.nasa.gov
AF: Jet Propulsion Laboratory California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AU: Armstrong, J W
EM: John.W.Armstrong@jpl.nasa.gov
AF: Jet Propulsion Laboratory California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AU: Asmar, S W
EM: Sami.W.Asmar@jpl.nasa.gov
AF: Jet Propulsion Laboratory California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AU: Ardito, A
EM: Ardito@iapetus.diaa.uniroma1.it
AF: Dipartimento di Ingegneria Aerospaziale ed Astronautica, Universita' di Roma "La Sapienza", Via Eudossiano, 18, Roma, 00184, Italy
AU: Di Benedetto, M
EM: mauro.dibenedetto@uniroma1.it
AF: Dipartimento di Ingegneria Aerospaziale ed Astronautica, Universita' di Roma "La Sapienza", Via Eudossiano, 18, Roma, 00184, Italy
AU: Graziani, A
AF: Dipartimento di Ingegneria Aerospaziale ed Astronautica, Universita' di Roma "La Sapienza", Via Eudossiano, 18, Roma, 00184, Italy
AU: Racioppa, P
EM: paolo.racioppa@uniroma1.it
AF: Dipartimento di Ingegneria Aerospaziale ed Astronautica, Universita' di Roma "La Sapienza", Via Eudossiano, 18, Roma, 00184, Italy
AB: The Cassini tour of the Saturnian system calls for DSN ground stations to track the spacecraft at X-band and Ka- band during five flybys of Titan for the purpose of determining the satellite's gravity field, including its Love number k2. This will constrain the models of interior structure. In particular, the determination of k2 will allow us to respond to the question of whether Titan contains an internal ocean. The first three flybys occurred on February 27, 2006, December 28, 2006, and June 29, 2007. Two additional flybys are planned in July 2008 and May 2010. The presentation will first focus on the estimation of the mass and quadrupole field of Titan from the first two flybys, carried out by the Cassini Radio Science Team using a short arc orbit determination technique (to avoid maneuvers), dual frequency downlink (to mitigate the effects of interplanetary plasma), and advanced water vapor radiometers (to calibrate the wet path delay). The first two flybys occurred intentionally while Titan was near apocenter on its orbit, so did not permit the determination of k2. The data from the two flybys were first independently fitted, and then combined in a multi-arc solution. Under the assumption that the higher degree harmonics are negligible, the gravity parameters from the combined, multi-arc solution are determined with relative accuracies of 2.8E-7 for the mass, 6.8E-3 for J2, and 3.6E-3 for C22. The excellent agreement (within 1.7 sigma) of the results from the two flybys analyzed independently further increases the confidence in the solution and provides an a posteriori validation of the dynamical model. The second part of the presentation will describe the method and expected results of the Love number measurement from the combination of the five flybys.
DE: 5709 Composition (1060)
DE: 5714 Gravitational fields (1221)
DE: 5724 Interiors (8147)
DE: 5749 Origin and evolution
DE: 5770 Tidal forces
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting