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  • 1. Presentation to: Robert T. Mitchell Cassini Program Manager Jet Propulsion Laboratory, California Institute of Technology February 10, 2011 Cassini Program Project Management Challenge Managing the Cassini Project’s Transition to Extended Mission Copyright 2010 California Institute of Technology. Government sponsorship acknowledged.
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  • 3. Cassini History
    • Launch on October 15, 1997, with ESA’s Huygens Probe
    • Seven year cruise to Saturn
    • Arrival and orbit insertion on July 1, 2004
    • Probe release on December 24
    • Descent through Titan’s atmosphere and probe data relay to Earth on January 14, 2005
    • Four-year prime mission orbital tour, 45 Titan encounters, 10 icy satellite encounters, 76 orbits
    • Twenty-seven month mission extension approved, 64 orbits, 28 Titan encounters, 8 Enceladus encounters, 3 with other smaller icy satellites
    • Equinox crossing in August, 2009
    • Seven-year second mission extension approved through September, 2017
    • 155 orbits, 54 Titan encounters, 11 Enceladus encounters, 5 other icy moon encounters
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  • 5. The Challenges – Top Level
    • Sell a second mission extension to NASA
      • Likely not to succeed at current budget
      • Define minimum “worthwhile” mission
    • Identify minimum funding level for reliable, worthwhile mission
      • Mission variables – tour complexity and observation design complexity
  • 6. Challenges – Lower Level
    • Rein in science appetite
      • Six years of optimized sequences and adequate funding
      • Move to resource constrained sequences
    • Descope a solidly entrenched operations team
    • Design and build new tools and processes in parallel with full-up operations
    • Build and validate new ground system – H/W and S/W
    • Design seven year tour consistent with science objectives, available funding, and remaining consumables
  • 7. Mission Summary
  • 8. Mission Drivers
    • Frequent satellite encounters with three orbit trim maneuvers per encounter
    • Overlapping sequence development and execution activities
      • Six at a time in prime and Equinox missions
    • Distributed science operations over nine time zones
    • Twelve body-fixed instruments with conflicting pointing requirements
  • 9. High Level Science Objectives
    • Study seasonal variations at Titan and Saturn
    • Investigate the Enceladus plumes
    • Increase mapping coverage of Titan’s surface
    • Determine the nature of Titan’s interior
    • Develop further understanding of the dynamics of Saturn’s rings
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  • 12. Policies for Solstice Mission Operations
    • No change in position on risk to flight hardware
    • Modest increase in risk to science data return acceptable for cost reduction
    • No unreasonable workloads to be allowed
    • Prioritization of science activities required before sequencing
    • Limit initial sequence design to what can be implemented
  • 13. Changes From Equinox and Prime Missions
    • Reduced overlapping sequence activities from six to three
    • Designed less complex tour (less frequent encounters, longer orbit periods)
    • Simpler observation sequences, less optimization and fine tuning
    • New guidelines and constraints on science sequence integration
    • Combined some functions to allow for more cross-training
    • Reduced DSN tracks from one per day to ~one every other day
    • Less optical navigation effort
    • Discipline focused periapses
    • Fewer meetings (telecons)
    • Reduced engineering support funding by 40%, science funding by 25%
  • 14. XXM Sequence Implementation Process Transition
  • 15. Why Did It Work?
    • Highly capable, experienced, and motivated team members
    • Ample lead time to do it right
    • Effective communications
    • Excellent systems engineering skills were available.
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