1. A Measurement of Titan´s Zonal Winds by the Huygens Doppler Wind Experiment: Michael Bird (Radiostronomisches Institut, Universität Bonn) And the DWE Team DPS Cambridge - Paper 2.01I Monday, 5 September 2005

2. Cambridge DPS, 5 Sep 2005 2 Huygens DWE The DWE Team M.K. Bird, R. Dutta-Roy, Y. Dzierma Radioastronomisches Inst., Univ. Bonn, Auf dem Hügel 71, 53125 Bonn, Germany M. Allison NASA Goddard Inst. for Space Studies, 2880 Broadway, New York, NY 10025 D.H. Atkinson Dept. of Elec. & Computer Engineering, Univ. of Idaho, Moscow, ID 83844 S.W. Asmar, W.M. Folkner, D.V. Johnston, R.A. Preston Jet Propulsion Laboratory, Caltech, 4800 Oak Grove Dr, Pasadena, CA 91109 P. Edenhofer Institut für HF-Technik, Universität Bochum, 44780 Bochum, Germany D. Plettemeier Elektrotechnisches Institut, Technische Univ. Dresden, 01062 Dresden, Germany G.L. Tyler Center for Radar Astronomy, Stanford University, Stanford, CA 94305 L.I. Gurvits, S.V. Pogrebenko, I.M. Avruch Joint Inst. for VLBI in Europe, P.O. Box 2, 7990 AA Dwingeloo, The Netherlands

3. Cambridge DPS, 5 Sep 2005 3 Huygens DWE DWE Concept (1) Goal: In situ determination of zonal wind speed along Huygens descent path Approach: Record Doppler effect on Huygens carrier signal => radial velocity

4. Cambridge DPS, 5 Sep 2005 4 Huygens DWE DWE Concept (2) Input parameters: 1.Huygens descent speed, 2.Huygens meridional speed 3.Huygens starting position 4.Cassini position & velocity 5.Earth-based station position & velocity

5. Cambridge DPS, 5 Sep 2005 5 Huygens DWE DWE Hardware TUSO on Huygens Probe Ultra-stable Oscillators (USOs) RUSO in Huygens Receiver on Cassini +

6. Cambridge DPS, 5 Sep 2005 6 Huygens DWE Cassini TCXO RUSO TCXO TUSO Channel B Channel A Earth “Channel C” Huygens Signal paths Huygens Data Huygens Receivers Huygens Probe NO POWER TCXO RUSO

7. Cambridge DPS, 5 Sep 2005 7 Huygens DWE DWE from Earth: Geometry Huygens antenna pointed only ~30° from Earth Better SNR than for VLA detection of Galileo Probe at Jupiter Probe-Earth vector projection onto horizontal nearly antiparallel to Probe- Orbiter projection  20º Titan Disk

8. Cambridge DPS, 5 Sep 2005 8 Huygens DWE Huygens Radio Tracking Net 10:18 UTC-GRT12:30 UTC-GRT GBT VLBA MK KP PTOV MK Parkes VLBA

9. Cambridge DPS, 5 Sep 2005 9 Huygens DWE Huygens Earth-Based Network Facility Start UTC Stop UTCComment GBT09:31:1012:15:00 DWE: Real-time RSR detection VLBA Fort Davis09:31:1013:45:00 VLBA North Liberty09:31:1013:15:00 VLBA Owens Valley09:30:0914:49:14DWE: No nodding – on Titan continuously VLBA Pie Town09:30:1114:15:04DWE: No nodding – on Titan continuously VLBA Los Alamos09:31:1014:00:00 VLBA Brewster09:31:1014:48:00 VLBA Kitt Peak09:31:1014:15:00DWE VLBA Mauna Kea09:31:1016:00:00DWE Parkes12:26:2316:00:00DWE: Real-time RSR detection Hobart11:13:1016:00:00 Ceduna10:13:1016:00:00 Mopra10:10:1016:00:00 Kashima09:31:1016:00:00 Shanghai10:01:1016:00:00

10. Cambridge DPS, 5 Sep 2005 10 Huygens DWE GBT Parkes

11. Cambridge DPS, 5 Sep 2005 11 Huygens DWE GBT: 14 Jan 2005 Huygens! (~ -171 dBm) Flux density  125 Jy 10:18:15 UTC-GRT 10 just noise

12. Cambridge DPS, 5 Sep 2005 12 Huygens DWE Huygens Frequency: GBT + Parkes 26-min gap GBT Parkes Cassini loss of link

13. Cambridge DPS, 5 Sep 2005 13 Huygens DWE Huygens Frequency: GBT + predicts 80-s gaps (VLBI)

14. Cambridge DPS, 5 Sep 2005 14 Huygens DWE Huygens Frequency: Parkes + Predicts predicted impact  f = +26.4 Hz 80-s gaps (VLBI)

15. Cambridge DPS, 5 Sep 2005 15 Huygens DWE Zonal Wind Velocity

16. Cambridge DPS, 5 Sep 2005 16 Huygens DWE Zonal Wind Height Profile

17. Cambridge DPS, 5 Sep 2005 17 Huygens DWE DWE: Preliminary Results 1. Zonal winds above boundary layer are PROGRADE 2. First in situ confirmation of TITAN’S SUPERROTATION 3. Huygens eastward drift: 3.75º (~166 km) 4. Low-velocity layer between 60-100 km –Stong positive/negative wind shear –Unexpected, presently unexplained 5. Considerable turbulence above 100 km 6. Near surface winds are weak (~1 m/s)

18. Huygens Ground Track Determination: A Comparison of DWE and DISR Results R. Dutta-Roy, B. Rizk, S.W. Asmar, D.H. Atkinson, M.K. Bird, M.W. Bushroe, E. Karkoschka, E.A. McFarlane, C. See, M.G. Tomasko, and the DWE and DISR Teams DPS Cambridge - Poster 45.09 Wednesday, 7 September 2005

19. A Preliminary Meteorological Interpretation of Correlated Huygens DWE and HASI Data M. Allison, F. Ferri, M.K. Bird, M. Fulchignoni, S.W. Asmar, D.H. Atkinson, G. Colombatti, G.L. Tyler and the DWE and HASI Experiment Teams DPS Cambridge - Poster 45.03 Wednesday, 7 September 2005