1 / 30

Cassini Tour Selection

Cassini Tour Selection. Dr. Kevin R. Grazier IS/SPE With Significant Viewgraph Assistance By: Linda Spilker Cassini Deputy Project Scientist July 26, 2005. History. Tour 89-01 was discussed in the Cassini Announcement of Opportunity (AO)

napua
Download Presentation

Cassini Tour Selection

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cassini Tour Selection Dr. Kevin R. Grazier IS/SPE With Significant Viewgraph Assistance By: Linda Spilker Cassini Deputy Project Scientist July 26, 2005

  2. History • Tour 89-01 was discussed in the Cassini Announcement of Opportunity (AO) • Discussions about creating a “new tour” began at very first PSG meeting (in December, 1990) • Tour 92-01 was created after Cassini descope. Very Galileo-like in its character. • mostly updated tour 89-01 for new Cassini arrival date - 2 -

  3. Tour 92-01 • Characteristics of 92-01 • 63 Orbits • 33 Titan flybys • 12 inbound, 21 outbound, 10 solar/earth occulations • 4 targeted icy satellite flybys: Enceladus, Dione, Rhea, Iapetus • 12 non-targeted flybys (d<50,000 km) • Saturn/ring occultations: 5 earth and sun during first 2 occultation sequences - 3 -

  4. Tour Trade Study • PSG and Project agreed to a tour design trade study, scheduled between 1993 and 1996 • Discipline Working Groups (Atmospheres, MAPS, Satellites, Rings) developed a list of tour geometry objectives and guidelines • DWG tour priorities generated over several PSG meetings • Finalized by DWGs at ESTEC PSG in May 1995 • Tour design tool (STOCK) provided to teams • With software and excel spreadsheets Cassini scientists could design a Titan-only tour • New orbit rotation technique identified (Titan 180 transfer) - 4 -

  5. Tour Design Considerations • Titan flyby strategy • Tour redesign implications of change in minimum altitude, number of flybys and occultations • Extent of CCW rotation at beginning of tour • Number of moderately inclined (20-50 deg) orbits and location during tour • Extent of CW rotation toward magnetotail • Maximum value of high inclination orbits • Saturn and Rings sun/earth occultation geometry strategy • Icy satellite flyby strategy for given tour rotation/inclination profile • Tour strategy relative to horseshoe/tadpole trapped particle risk regions • Ground system requirements - 5 -

  6. Selecting a Tour • Orbiter workshop held in July, 1995 • 3 IS-led interdisciplinary teams evaluated 8 classes of tours (38 Titan-only tours) • Identified driving requirements and suggested possible compromise tours • At end of tour design trade study, 17 Titan-only tours (T1 – T17) were available for further study - 6 -

  7. Some Tours Looked Rather Familiar - 7 -

  8. Others…. Didn’t - 8 -

  9. Selecting a Tour • At 8/96 PSG, added one class of tour for further study– T18 • Three tours quickly emerged as favored: - 9 -

  10. T2 • Quickly eliminated largely because of low science return. - 10 -

  11. T9 • LOVED by MAPS, Rings, Titan (two 180 transfers; 51 Titan flybys)! • Too difficult operationally (too many consecutive 16-day orbits) - 11 -

  12. The Winner Is: T18 • At 3/99 PSG selected T18-1 as final tour • Less science return than T9-1 • Still difficult operationally, but we decided to “bite the bullet”. • Since T18-1, there have been 4 major revisions and at least 14 minor. - 12 -

  13. Current Reference Tour • 74 Orbits • 45 Titan flybys • 8 targeted icy satellite flybys: Phoebe, Enceladus (3), Dione, Rhea, Hyperion, Iapetus • ~30 non-targeted flybys (d < 100,000 km) • Many Saturn/ring occultation opportunities • Early, middle and late in tour • One Titan 180 transfer • One high inclination sequence at end of tour - 13 -

  14. Our Pre-launch Goals • Scan Platform Working Group: 11/91 • Sequencing process must start early, before launch, if possible • Tour fully designed before SOI (minimizes impact of burnout, divorce, suicide, murder, etc. during tour) - 14 -

  15. Cassini Tour T18-5 • Looking down from Saturn’s North Pole • Outer dotted circle: Orbit of Iapetus • Inner dotted circle: Orbit of Titan • Sun along +X Axis – Plot shows phase Looking in Saturn’s Ring Plane Excursions in inclination different from Galileo All units in Rs - 15 -

  16. CASSINI TOUR T18-5Orbit Insertion and Huygens Mission All units in Rs - 16 -

  17. CASSINI TOUR T18-5Huygens Mission – Rev B Probe Release All units in Rs - 17 -

  18. CASSINI TOUR T18-5Huygens Mission – Rev B Probe Mission All units in Rs - 18 -

  19. CASSINI TOUR T18-52005 FEB 15 to 2005 SEP 07 Mid-Rev 3 to Mid-Rev 14Occultation Sequences All units in Rs - 19 -

  20. CASSINI TOUR T18-52005 FEB 15 to 2005 SEP 07 Mid-Rev 3 to Mid-Rev 14Occultation Sequences All units in Rs - 20 -

  21. CASSINI TOUR T18-52005 SEP 07 to 2006 JUL 22 Mid-Rev 14 to Mid-Rev 26 Magnetotail and Icy Satellites All units in Rs - 21 -

  22. CASSINI TOUR T18-52005 SEP 07 to 2006 JUL 22 Mid-Rev 14 to Mid-Rev 26 Magnetotail and Icy Satellites - 22 -

  23. CASSINI TOUR T18-52006 JUL 22 to 2007 JUN 30 Mid-Rev 26 to Mid-Rev 47 180 Transfer: Rings and MAPS All units in Rs - 23 -

  24. CASSINI TOUR T18-52006 JUL 22 to 2007 JUN 30 Mid-Rev 26 to Mid-Rev 47 180 Transfer: Rings and MAPS - 24 -

  25. CASSINI TOUR T18-52007 JUN 30 to 2007 AUG 31 Mid-Rev 47 to Mid-Rev 49 Iapetus Flyby Preparation/Icy Satellites All units in Rs - 25 -

  26. CASSINI TOUR T18-52007 AUG 09 to 2007 SEP 14Rev 49 Titan Gravity Assist and Iapetus Flyby All units in Rs - 26 -

  27. CASSINI TOUR T18-52007 AUG 09 to 2007 SEP 14Rev 49 Titan Gravity Assist and Iapetus Flyby - 27 -

  28. CASSINI TOUR T18-52007 AUG 31 to 2008 JUL 01 Mid-Rev 49 to EOM High Inclination Revs: Rings and MAPS All units in Rs - 28 -

  29. CASSINI TOUR T18-52007 AUG 31 to 2008 JUL 01 Mid-Rev 49 to EOM High Inclination Revs: Rings and MAPS - 29 -

  30. http://saturn.jpl.nasa.gov http://ciclops.org

More Related