Quarterly 17/18/2007 INMS Team Fourth Quarter Report October, 2007 INMS Quarterly

Quarterly 27/18/2007 INMS Quarterly Accomplishments SCIENCE HIGHLIGHT: Combined INMS and CAPS analysis of Titan’s ionosphere demonstrate the chemical complexity in Titan’s upper atmosphere. SCIENCE HIGHLIGHT: Modeling by the INMS team indicates that energetic ions observed by MIMI have important consequences for the ionosphere and upper atmosphere. SCIENCE HIGHLIGHT: T36 provided excellent data on the high southern latitude ionosphere and atmosphere of Titan. Although, the altitude density structure is different than in the north the minor species composition at first appearance is quite similar. INMS, CAPS, and RPWS are continuing a joint analysis of the complete atmosphere and ionosphere data set for Titan in hopes of understanding the role of coupled ion and neutral chemistry in aerosol formation. In addition to routine science planning and operations support INMS has provided Cassini project support for determination of the flyby latitude of E3. Analysis of the INMS Titan atmospheric data set in support of TAMWG continues to show high-altitude atmospheric variability that is a function of latitude with converging densities below 1000 km. CALIBRATION HIGLIGHT: INMS ion calibration continues to try and improve the RADAR pass performance of INMS.

Quarterly 37/18/2007 INMS Quarterly SCIENCE HIGHLIGHT: Combined INMS and CAPS analysis of Titan’s ionosphere demonstrate the chemical complexity in Titan’s upper atmosphere. White points indicate CAPS IBS data points Blue indicates INMS simulation of overlap region in ion data T18 Ionosphere

Quarterly 47/18/2007 INMS Quarterly SCIENCE HIGHLIGHT: Modeling by the INMS team indicates that energetic ions observed by MIMI have important consequences for the Titan upper atmosphere. Comparison of Energy Deposition into Titan’s Atmosphere vs. Altitude Ion precipitation begins to dominate in the altitude range where one sees an increase in chemical complexity

Quarterly 57/18/2007 INMS Quarterly SCIENCE HIGHLIGHT: T36 provided excellent data on the high southern latitude ionosphere and atmosphere of Titan. Although, the altitude density structure is different than in the north the minor species composition at first appearance is similar.

Quarterly 67/18/2007 INMS Quarterly – Plans Upcoming close flybys of Titan’s atmosphere in the southern hemisphere will give INMS an opportunity to study the atmospheric structure in the southern hemisphere and to see if the colder temperatures and lower densities are symmetrically observed at both poles. INMS is finalizing plans and models for the upcoming close flyby of Enceladus on E61 to help determine the optimum trade between science and risk for the close flyby that is currently planned for 25 km above the surface. INMS is beginning planning for the high latitude (auroral) flybys of Saturn’s upper atmosphere. INMS continues to try and find a way to improve ion coverage during RADAR flybys by improving calibration (see following slides).

Quarterly 77/18/2007 INMS Engineering Unit Sensor Characterization Code 699, Goddard Space Flight Center, uses the INMS backup sensor with laboratory electronics, flight pulse counter and flight quadrupole mass analyzer systems. Setup system for ion mode testing with 6 nominal energies: 2 eV, 3 eV, 5 eV, 11 eV, 21 eV, 35 eV. Ar is the gas used in the ion gun; there is no magnetic m/z filtering so the ion beam consists of Ar + and Ar ++ (~10% of beam). Readout of pressure monitors, 2 angle encoders, 1 translation encoder, ion beam current plus the normal instrument mass scans, energy scans and quad-bias scans were implemented. Software system updated. Format of data files for input to the SwRI ION system finalized but not fully tested. During the setup period, when SwRI was present, the laboratory computer began malfunctioning. The computer has been replaced along with the monitor. Preliminary study done for expanding the ion beam angle response using the 4 deflectors d1-d4 in the open source. Open source deflectors d1-d4

Quarterly 87/18/2007 INMS Flight Unit Operation Characterization A simple test was done with d1-d4 set at ground potential (normal) and optimized (optimized) individually for maximum signal at 21 eV Ar +. Optimization increased the angular response from about 2 degrees to more than 15 degrees for a Y-axis rotation. In this case, deflector potentials of the order of several volts needed on the d1-d4 elements. Ion mode characterization needs more than one person and is currently on hold. By increasing the angular response during a Radar pass the useful altitude range of INMS can be increased for ion mode.

Quarterly 97/18/2007 INMS PRESENTATIONS GIVEN FROM OCT 2006 to OCT 2007: 1. Oct DPS meeting: Titan’s Plasma Environment, invited talk, T. E. Cravens and INMS team. 2. Joint CAPS/INMS meeting on 11/13-11/14 of 2006 in Charlottesville, VA: Models of Thermal and Superthermal Electrons in Titan's Ionosphere, Ina Robertson, Thomas E. Cravens, Andrew Coates, Jan-Erik Wahlund, William Rowland, Hunter Waite, Andrew Nagy, Yingjuan Ma, F.M. Neubauer, and C. Bertucci 3. Joint CAPS/INMS meeting on 11/13-11/14 in Charlottesville, VA: Ion Density Data from INMS (plus some modeling) - Nightside (T5) and Dayside (T17, T18): T. Cravens and INMS team 4. Fall American Geophysical Union meeting in San Francisco: Solar Radiation and Magnetospheric Electron Sources of Titan’s Ionosphere: Model Comparisons with Cassini Data. T. E. Cravens, I. P. Robertson, J. H. Waite Jr. et al.. 5. Fall American Geophysical Union meeting in San Francisco: Models of Thermal and Superthermal Electrons in Titan's Ionosphere, Ina Robertson, Thomas E. Cravens, Andrew Coates, Jan-Erik Wahlund, William Rowland, Hunter Waite, Andrew Nagy, Yingjuan Ma, F.M. Neubauer, and C. Bertucci 6. Colloquium at the University of Georgia chem dept. on Feb. 13, Titan’s Upper Atmosphere and Ionosphere as Seen by the Cassini Ion and Neutral Mass Spectrometer; T. E. Cravens (University of Kansas) with I. P. Robertson, J. H. Waite, Jr., J.-E. Wahlund, A. J. Coates, J. D. Clark, D. T. Young, and INMS team 8. May 17, 2007: Magnetospheric Sources of Titan's Ionosphere, presentation given by Tom Cravens at Cassini MAPS Workshop at the University of Iowa. 9. May 17, 2007: Models of Thermal and Superthermal Electrons in Titan's Ionosphere, presentation given by Ina Robertson at Cassini MAPS Workshop at the University of Iowa. 10. June 25, 2007, Recent discoveries in planetary aeronomy, T. Cravens, at ISSI Comparative Aeronomy Workshop in Bern Switzerland. 11. August 28, 2007, Response of Titan’s Ionosphere to Solar and Magnetospheric Inputs, T. Cravens, at ISSI Titan Aeronomy Workshop in Bern Switzerland.

Quarterly 107/18/2007 INMS PAPERS: Co-author on: J. H. Waite, Jr. et al., The Process of Tholin Formation in Titan’s Upper Atmosphere, in Science, T. E. Cravens, I. P. Robertson, J. H. Waite, R. Yelle, V. Vuitton, et al. "Ionospheric composition effects of superthermal electron precipitation on the nightside of Titan: Model comparisons with Cassini data", in preparation, I. P. Robertson, T. E. Cravens, J.-E. Wahlund, A. J. Coates, et al., "Energetics of the Titan ionosphere: model comparisons with Cassini electron temperature data", in preparation, T. E. Cravens, et al., Energetic ion precipitation at Titan, to be submitted to Geophysical Research Letters in Oct Yelle, R.V., N. Borggren, V. de la Haye, W.T. Kasprzak, H.B. Niemann, I. Müller-Wodarg, and J.H. Waite Jr., The vertical structure of Titan’s upper atmosphere from Cassini Ion Neutral Mass Spectrometer measurements. Icarus, 182, (2006), Waite, J.H. Jr., D.T. Young, T.E. Cravens, A.J. Coates, F.J. Crary, B. Magee, J. Westlake, “The Process of Tholin Formation in Titan’s Upper Atmosphere,” Science, 316, 870 (2007). Balsiger, H., K. Altwegg, P. Bochsler, P. Eberhardt, J. Fischer, S. Graf, A. Jackel, E. Kopp, U. Langer, M. Mildner, J. Müller, T. Riesen, M. Rubin, S. Scherer, P. Wurz, S. Wüthrich, E. Arus, S. Delanoye, J. De Keyser, E. Neefs, D. Nevejans, H. Reme, C. Aoustin, C. Mazelle, J.-L. Medale, J.A. Sauvaud, J.-J.Berthelier, J.-L.Bertaux, L.Duvet, J.-M. Illiano, S.A. Fuselier, A.G. Ghielmetti, T. Magoncelli, E.G. Shelley, A. Korth, K. Heerlein, H. Lauche, S. Livi, A. Loose, U. Mall, B. Wilken, F. Gliem, B. Fiethe, T. I. Gombosi, B. Block, G.R. Carignan, L.A, Fisk, J.H. Waite Jr., D.T. Young, and H. Wollnik, “Rosina-Rosetta Orbiter Spectrometer For Ion And Neutral Analysis,” Space Science Reviews, doi: //s , (2007). Tucker, Orenthal; Johnson, R. E.; Ledvina, S. A., “Plasma Ion and Proton Induced Heating and Sputtering of Titan's Atmosphere,” American Astronomical Society, DPS meeting #39, #56.04 (10/2007). S. A. Ledvina, T. E. Cravens, I. P. Robertson, O. J. Tucker, R. E. Johnson and D. G. Mitchell, ISSI Workshop “The precipitation of energetic ions into Titan’s atmosphere and their implications on Titan Aeronomy,” 08/2007

Quarterly 117/18/2007 INMS De La Haye, V.; Waite, J. H.; Johnson, R. E.; Yelle, R. V.; Cravens, T. E.; Luhmann, J. G.; Kasprzak, W. T.; Gell, D. A.; Magee, B.; Leblanc, F.; Michael, M.; Jurac, S.; Robertson, I. P., “Cassini Ion and Neutral Mass Spectrometer data in Titan's upper atmosphere and exosphere: Observation of a suprathermal corona,” Journal of Geophysical Research, Volume 112, Issue A7, CiteID A07309, 07/2007. S. A. Ledvina, “Magnetosphere-Satellite Interactions,” ISSI Workshop on Comparitive Aeronomy, (06/2007). Hartle, R. E.; Sittler, E. C.; Shappirio, M. D.; Johnson, R. E.; Luhmann, J. G.; Ledvina, S. A.; Cooper, J. F.; Coates, A. J.; Szego, K.; Burger, M. H.; Simpson, D. G.; Crary, F.; Young, D. T., “Saturn Magnetosphere Ion Erosion by Titan: Penetration and Loss of Water Group Ions in Upper Atmosphere,” American Geophysical Union, Fall Meeting 2006, abstract #P13A-0161 (12/2006). Ledvina, S. A.; Luhmann, J. G.; Cravens, T. E.; Dandouras, I.; Garnier, P.; Johnson, R. E., Sensitivity of Titan's ENA emissions to incident ion flux and exospheric density American Geophysical Union, Fall Meeting 2006, abstract #SM23A-0280 (12/2006). Cravens, T. E.; Robertson, I. P.; Waite, J. H.; Kasprzak, W. T.; Yelle, R. V.; Vuitton, V.; Clark, J.; Luhmann, J. G.; Ledvina, S. A.; McNutt, R. L.; Ip, W.; Mueller-Wodarg, I.; Wahlund, J.; Coates, A. J., “Solar Radiation and Magnetospheric Electron Sources of the Ionosphere of Titan: Model Comparisons With Cassini Data,” American Geophysical Union, Fall Meeting 2006, abstract #P13A-0162 (12/2006). Hartle, Richard; Sittler, E.C., Jr.; Shappirio, M.D.; Johnson, R.E.; Luhman, J.G.; Ledvina, S.A.; Cooper, J.F.; Coates, A.J.; Szego, K.; Burger, M.H.; Simpson, D.G.; Crary, F.; Young, D.T., “Saturn Magnetosphere Ion Erosion by Titan: Penetration and Loss of Water Group Ions in Upper Atmosphere,” American Astronomical Society, DPS meeting #38, #36.05; Bulletin of the American Astronomical Society, Vol. 38, p.549, 09/2006. Ledvina, Stephen; Luhmann, J. G.; Johnson, R. E.; Michael, M.; Tucker, O. J.; Mitchell, D.; Dandouras, J., The Response of Titan's Atmosphere to Energetic Magnetospheric H+ Precipitation, American Astronomical Society, DPS meeting #38, #27.02; Bulletin of the American Astronomical Society, Vol. 38, p.527, 09/2006. Sittler, Edward C.; Hartle, R. E.; Shappirio, M.; Simpson, D. J.; Cooper, J. F.; Burger, M. H.; Johnson, R. E.; Bertucci, C.; Luhman, J. G.; Ledvina, S. A.; Szego, K.; Coates, A. J.; Crary, F.; Young, D. T., “Titan Ion Composition at Magnetosphere-Ionosphere Transition Region,” American Astronomical Society, DPS meeting #38, #27.01; Bulletin of the American Astronomical Society, Vol. 38, p.527 (09/2006).

Quarterly 127/18/2007 INMS Luhmann, J. G., “Comparative Nonmagnetized Obstacles: Mars, Venus, Titan,” 36th COSPAR Scientific Assembly. Held July 2006, in Beijing, China. Meeting abstract from the CDROM, #2106, 00/2006 Johnson, R. E.; Michael, M.; Tucker, O. J.; Shematovich, V. I.; Luhmann, J. H.; Ledvina, S. A., “Plasma-ion- induced sputtering and heating of Titan's atmosphere,” European Planetary Science Congress Berlin, Germany, September 2006., p.98, 00/2006