Cassini Significant Event Report

For Week Ending 11/26/04

Due to the Thanksgiving holiday, the reporting period for this week covers three days instead of the usual five. The most recent spacecraft telemetry was acquired from the Madrid tracking station on Monday, November 22. The Cassini spacecraft is in an excellent state of health and is operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" web page located at .

Apoapsis - the point in the orbit farthest from Saturn - for the current orbit occurred on November 21. At that time the Ultraviolet Imaging Spectrograph (UVIS) made a mosaic of Saturn's inner magnetosphere in neutral and ion photon emissions to derive the distribution and density of atomic and molecular species. UVIS also continued to examine the F-Ring to monitor changes in ring reflectance properties.

Additional science activities included the continuation of Imaging Science Subsystem (ISS) observations of small satellites for orbit determination and to improve understanding of short and long term dynamical evolution. ISS also continued capturing of movies in search of the elusive Saturnian Ring spokes, which have not been seen by Cassini thus far.

On-board activities this week included the execution of an Ion and Neutral Mass Spectrometer (INMS) operating threshold test, Orbital Trim Maneuver (OTM) #6, and the muting of the instruments in preparation for Probe Checkout #16 (PCO). PCO is a mini sequence designed to exercise the instruments on board the Probe and prepare it for the relay mission.

OTM-6 was successfully completed on the spacecraft Saturday, November 20. This maneuver, performed near Rev-A apoapsis, targets Cassini to Titan for the Tb flyby.

The main engine (ME) burn began at 10:10 Pacific Standard Time with a burn duration of 3 seconds - the shortest duration main engine maneuver performed to date - giving a delta-V of 0.4 m/s.

As was mentioned last week, development continues for the S06 Titan-b live Inertial Vector Propagator (IVP) update. The process kicked off this week and over the weekend the science teams reviewed the materials relevant to the update. On Monday at the go/no go meeting it was determined that the update was necessary for ISS only. The result will be an update for one vector and one observation. Test files have been transferred to the Integrated Test Laboratory (ITL) and the test will begin on Tuesday, November 23.

Sequence development is ongoing for tour sequences S06 through S12, and S37 through S41.

Sequences S07 and S08 continue in the Science and Sequence Update Process (SSUP). A Science Allocation Panel meeting was held as part of the S08 process and the Preliminary Sequence Integration and Validation 1 (PSIV) products were processed and are available for review.

Products were delivered for Preliminary Port 1 by all participating teams as part of the Science Operations Plan Implementation process for S39 and S40.

On Friday, November 19, Deep Space Mission Systems (DSMS) held a successful Cassini-Huygens probe release, relay, and data playback Mission Event Readiness Review. The review board unanimously agreed that the DSMS is ready to support the Huygens Probe release and data playback.

A program internal science talk was given this week by one of the Visual and Infrared Mapping Spectrometer (VIMS) team members on The Latest VIMS Results on Titan and the Icy Satellites.

Cassini Outreach conducted a Cassini workshop for ten members of the Natural History Museum of Los Angeles education and outreach staff this week. Activities included talks by Cassini scientists, demonstration of hands-on educational activities from the Cassini education webpage, and a mission overview and science update.