Cassini Significant Event Report

For Week Ending 01/17/03

The most recent spacecraft telemetry was acquired from the Madrid tracking station on Tuesday, January 14. 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 clearing of the ACS high water marks, Radio and Plasma Wave (RPWS) High Frequency Receiver calibrations, conclusion of Gravitational Wave Experiment #2 (GWE), return to normal cruise science, start of Cosmic Dust Analyzer Saturn dust stream observations, and uplink of Visual and Infrared Mapping Spectrometer (VIMS) flight software version 6.1. VIMS team members have prepared a mini-sequence to load and exercise the new FSW during its Fomalhaut observation activity on DOY 022.

A set of Solid State Recorder (SSR) pointer reset commands caused the playback and record pointers to occupy the same location. This caused the SSR to stop recording and playing back science data, and the Command and Data Subsystem to mark SSR-B as 'sick'. A command file was built to reconfigure the SSR and sent to the spacecraft, which restored normal SSR operations and status.

The six-week GWE #2 ended Tuesday morning, January 14. Most activities at the DSN stations were normal during the last week, although there were short periods of antenna pointing problems or lost lock, with the resultant minor gaps in uplink and downlink data. During the final pass of GWE #2, commands executed on board the spacecraft to turn off the Ka-band Exciter and Ka-band Traveling Wave Tube Amplifier. The Ka-band Translator remains on. The Radio Science Team and the Instrument Operations-Radio Science Subsystem operations team have expressed appreciation for the assistance they received from those on the Cassini Project, JPL Divisions, and the Deep Space Network who contributed to the success of GWE.

The Command and Data Subsystem (CDS) Team began an end-to-end system mode test of their procedures for the uplink and checkout of the Version 9 flight software. The test will complete next week.

The Spacecraft Operations Office successfully completed the first of a series of Probe Relay Operational Verification Tests to test a portion of ground operations during the probe mission. The preliminary input products for tour sequences S15/S16 were delivered last week and error reports were created and delivered to the teams. The official port 1 delivery occurs next week.

A Project Briefing for the C37 cruise sequence was held this week. The Project approved this integrated plan for implementation.

Additional information about Cassini-Huygens is online at

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.

Media Relations Office

Jet Propulsion Laboratory

California Institute of

National Aeronautics and Space

Pasadena, Calif. 91109.
Telephone (818) 354-5011