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Significant Event Report for Week Ending 11/21/2003

Cassini Significant Event Report

For Week Ending 11/21/03

The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Wednesday, November 19. The Cassini spacecraft is in an excellent state of health and is operating normally. Information on the spacecraft's position and speed can be viewed on the "Present Position" web page.

On-board activities this week included Cassini Plasma Spectrometer flight software normalization, an Ion and Neutral Mass Spectrometer checkout, a Visual and Infrared Mapping Spectrometer Instrument Expanded Block (IEB) uplink, conclusion of a Radio and Plasma Wave Science (RPWS) eight day cyclic and start of a ten day SOI test, conclusion of the Magnetospheric Imaging Instrument Saturn Orbit Insertion IEB demonstration, and continuation of GWE #3.

The Radio Science team continues to collect coherent X-band data, and when available, Ka1 data as part of GWE #3. During the first eight days of continuous DSN coverage, the X-band transmitter at DSS-25 tripped off four times causing a loss of about 130 minutes of coherent X and Ka1 data. The initial monopulse problems of the first day of the experiment were determined to be due to a procedural error. Since the correction of the error, monopulse has been behaving normally. During the DSS-25 pass on DOY 316, a strong spurious signal was observed crossing the Ka-band downlink signal as seen in the open-loop recording bandwidth. The DSN has been informed of this in order to investigate the source of the interference.

Official port#2 of the Science Operations Plan implementation process for tour sequences S05 and S06 occurred this week. The products were merged and are currently being run through Kinematic Prediction Tool/ Inertial Vector Propagator.

A wrap-up meeting was held as part of the Science Planning Team process for cruise sequence C43. The sequence generation process will begin next week.

The Spacecraft Operations Office (SCO) delivered the Solaris 9 port of ground software tools Alf_Tool V10.1, ACKT V1.1, and PGT V9.0. The Alf tool is used to uplink flight software for both engineering and instrument subsystems. ACKT and PGT are used by the AACS team to develop engineering subsequences. SCO completed the procedure to power-off the second Power Converter Units in each of the two Solid State Recorders. This was done to extend life on the second units.

The Saturn Orbit Insertion (SOI) Risk Review board report has been released. The risk review was held at JPL at the end of October, and was chartered to provide an independent assessment of the Cassini project's risk preparedness for the Saturn Orbit Insertion phase of the mission. Two success criteria were defined: 1) Cassini has implemented the appropriate processes for risk identification, and 2) the appropriate level of risk mitigation measures are (or will be) in place for SOI.

The consensus of the review board was that the Cassini project is very well prepared for Saturn Orbit Insertion from almost any point of view. Key personnel, from the project management through the individual cognizant engineers, are knowledgeable about the major risks associated with SOI and are actively pursuing risk mitigation activities. In addition, the formal risk identification process has been exceedingly thorough. Risk Management and Contingency Plan efforts have been rigorously disciplined, providing a near textbook approach to the implementation of these two operational system engineering activities. More than ample time has been allocated for the critical software and sequence testing efforts. The review board did find some areas where additional effort may reduce the project risk even more. These areas are covered in the findings and recommendations listed within the report.

The Uplink Operations team delivered an updated SOI initialization sequence, a merged CDS and AACS initial conditions file, and an SOI vector update to the Integrated Test Laboratory for an upcoming SOI test. A delivery coordination meeting was held for two versions of the Mission Sequence Subsystem (MSS). MSS D10.0.1 cleaned up the size of the Science Opportunity Analyzer tool. Previously the tool had been delivered with unnecessary java components, which ate up large amounts of disk space. MSS D10.1 incorporated changes in the command database for three updated CIRS commands necessary to support their flight software checkout.

An SRCR delivery meeting was held for the CAPS v4.0.1 flight software. The software is planned for uplink to the spacecraft in mid December.

Imaging Science Subsystem Pre-commanding Tool software was provided to the project software library. Test plans are currently being formulated by Instrument Operations.

Outreach personnel attended a final read-through of the Cassini Literacy Program in Berkeley, CA with Bay Area Writing Project, Caltech Precollege Science Initiative Program and Project FIRST. This program will go online January 2004.

The Cassini planetarium show "Ring World" is now opening across the country. A DVD version is being pressed and will be available the first week in December.

Jupiter, our solar system's most massive planet, was captured in the most detailed global color view ever seen, by the narrow-angle camera on board the Cassini spacecraft. The view was acquired on December 29, 2000 during closet approach to the gas giant while en route to Saturn. The narrow angle camera took a series of high-resolution images at a distance of approximately 10 million kilometers. This allowed the Cassini imaging team to produce this new global view. The Jupiter portrait is available at the JPL photo journal at http://photojournal.jpl.nasa.gov and at the Cassini Imaging Team's website at http://ciclops.org .

On November 14-15, Saturn and its ring system passed in front of an 8.4-magnitude star in Gemini. Observers with 8-inch or larger telescopes watched in fascination as the star leisurely faded in and out of view behind the various rings, gaps, and the open space between the rings and the ball of Saturn itself. For a diagram of the star's apparent path behind Saturn and the rings, visit SkyandTelescope.com and click Observing Highlights. Or just click on this link: http://SkyandTelescope.com/observing/objects/occultations/article_1102_1.asp

Additional information about Cassini-Huygens is online at http://saturn.jpl.nasa.gov.

Cassini will begin orbiting Saturn on July 1, 2004, and release its piggybacked Huygens probe about six months later for descent through the thick atmosphere of the moon Titan. Cassini-Huygens is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Office of Space Science, Washington, D.C.

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