Cassini Significant Event Report

For Week Ending 02/22/02

The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Wednesday,
February 20. 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.


Instrument activities this week include a Radio Science Subsystem (RSS) Ultra Stable Oscillator characterization, and Periodic Instrument Maintenance.


Spacecraft activities this week included the completion of the Spacecraft Operations Office (SCO) procedure
to change the fault protection safing response default telemetry mode to 10 bps, and load module index
patches to RAM for both Command & Data Subsystem (CDS) strings and the SSR. Operations personnel
received official notification of the changes upon completion of the procedure. Additional spacecraft activities
included a memory readout of online CDS state matrix, an AACS Clear High Watermark, and an
autonomous CDS Solid State Recorder memory load partition repair.


SCO Power & Thermal personnel reported observing that the Imaging Science Subsystem (ISS) had
increased in temperature by about 10 deg C, and was drawing an additional 1.5W of power. ISS
investigated and determined a possible Narrow Angle Camera (NAC) CCD sensor failure, which, in turn, led
to a false reading of a cooler temp and turned ON the CCD performance heater. The ISS team is working a
recovery plan for next week to power cycle the NAC and Wide Angle Camera (WAC), and reload flight
software. It is hoped that this activity will reset the sensor and that no further action will be necessary.


The C31 background sequence has solidified and further changes are not anticipated prior to uplink. An
Integrated Test Laboratory (ITL) procedure walkthrough for the Radio and Plasma Wave Science (RPWS),
and Ultraviolet Imaging Spectrometer (UVIS) flight software uploads was held and the necessary files have
been generated for next week's test.


A three day technical design and risk review for Saturn Orbit Insertion began this week. Presentations will
be made by members of SCO, Mission Planning, and Mission Assurance.


A Mission Sequence Subsystem D8 Module Functionality Design Review was held this week. The review
was geared toward science users describing the functionality of the modules to be implemented in this
delivery. No significant issues were brought up in the review. Participants have until the end of the week to
submit any additional issues or concerns.


A delivery review was held for Multimission Image Processing Laboratory software Version 27.0. Several
Cassini specific upgrades to ISS and Visual and Infrared Mapping Spectrometer (VIMS) functionality were
delivered and accepted by Deep Space Mission Services.


The RPWS FSW 2.5.0 and UVIS FSW 1.3.0 ALF text files were approved for Uplink at a Delivery
Coordination Meeting Software Requirement Certification Review.



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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