Cassini Significant Event Report

For Week Ending 02/08/02

The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Wednesday,
February 6. 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.


The C30 sequence continues to execute as planned. Science activities include commanding for the Magnetometer
Subsystem (MAG) to set the Vector Helium Magnetometers bit to OFF state, and the conclusion of the
Imaging Science Subsystem (ISS) decontamination and Visual and Infrared Mapping Spectrometer
Image/Occultation mini-sequences.


Preliminary results from the ISS decontamination mini-sequence show a significant improvement for the
Narrow Angle Camera. The C30 decontamination cycle lasted approximately 7 1/2 days and reached about
+4 degrees C. This was several degrees above the C28 cycle as the replacement heaters were also powered
on. Final results should be available next week and will be followed by discussions of further decontamination
activities.


Other spacecraft activities included clearing of the AACS high water marks, an autonomous Command &
Data Subsystem Solid State Recorder Memory Load Partition repair, and an attitude control reaction wheel
friction test. Results from the test were normal.


The C31 preliminary Sequence Integration & Validation (SI&V) products were released this week. Members
of the Sequence Team reviewed the package and submitted desired Sequence Change Requests (SCR). The
SCRs will be dispositioned in the C31 SI&V SCR approval meeting to be held next week.


Science Planning (SP) reported the publication of a final report for the Satellite Orbiter Science Team (SOST)
Science Uplink Verification (SUPV) activity. SP activities included a full set of TWT meetings to continue the
integration of the orbits associated with the next delivery milestone, which includes orbits 10 through 15, and a
Titan Orbiter Science Team (TOST) meeting to refine the integration details associated with the recent T6/T7
trade.


The Spacecraft Office reported the Attitude Control flight software team delivered version 8.5.0. This is the
first version containing the energy cutoff algorithm for the Saturn orbit insertion burn and will be used for
system mode testing. In addition, the Attitude Control ground software developers delivered the preliminary
set of target options to Spacecraft Operations and Uplink Operations for early test and evaluation. These
comprise the full set of options for the Mission Sequence System D8 delivery.


The Cassini Program conducted a NASA Quarterly Review on Monday, February 4.


UVIS 1.3.0 instrument flight software was delivered to the Program Software Library.
Significant progress has been made in the Risk Management area, following a Program wide review of the
Significant Risk List. The overall risk posture of the Program has been reduced due to effective mitigation
efforts. Redundancy in several risk statements has been eliminated to create a crisp list for Risk Management
during Mission Operations.


A review and redesign of the proposed Telemetry Delivery System architecture for tour support has been
implemented due to changing storage system costs, and lack of adequate existing expertise with complex
storage array systems.


The Cassini-Huygens outreach and education website, currently hosted at: http://www.jpl.nasa.gov/cassini,
has been relocated to a new, enhanced environment. In conjunction with the move, a new domain name has
been established for the Cassini-Huygens site. The new address is http://saturn.jpl.nasa.gov. This change will
take effect on February 5, 2002.



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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