Cassini Significant Event Report

For Week Ending 09/05/03

The most recent spacecraft telemetry was acquired from the Madrid tracking station on Wednesday, September 3. 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 attitude control high water marks, Radio and Plasma Wave Science (RPWS) High Frequency Receiver calibrations and high rate observations, and uplink of an Imaging Science Subsystem memory load. Members of the Huygens team reported successful results from last week's probe mute test. With the participating orbiter instruments muted, all commands sent from the orbiter to the probe were successfully registered.

Cassini and Huygens have officially released the 56 kilobit per second (kbps) NASA Integrated Service Network (NISN) data line between JPL and the European Space Operations Center (ESOC). In its place, the projects will use a 384 kbps NISN data line that is shared with the Integral project. This will have a large potential benefit for both the probe and orbiter missions. During a demonstration of the transfer of the probe data during the Command and Data System Version 9 flight software checkout last spring, the 56 kbps line backed up significantly. Testing during August on the new line has shown data rates of between 210 kbps and 300 kbps allowing data transfer several times faster than before. This will allow ESOC more rapid access to the probe data and will allow for the earlier release of the on-board recorders for further data collection after the probe mission.

A delivery coordination meeting was held for the Maneuver Automation System version 3.0. New functionality for the software includes and enhanced user interface to simplify parameter inputs and view outputs; an interface to the reaction wheel bias tool; "one button" architecture to bind together Navigation and Spacecraft Operations Office processes into a seamless process. This system will be first used in operations for Trajectory Correction Maneuver 19a, which will execute next week.

The JPL Navigation Section held a one day review of the Cassini Navigation Team's preparations for Saturn approach and orbital operations. The review went well. While the board generated a small number of follow on actions for the team, the consensus was that the team was in good shape and well prepared for Saturn operations. A separate review concentrating exclusively on the Huygens probe mission will be held later.

The application window for new members to the Saturn Observation Campaign (SOC) is now officially closed for 2003. As of August 30, there were 235 participants. 135 are new, 150 reside in the USA, and 85 reside in foreign nations. For the 2003-2004 year, SOC members reside in 34 US states, Puerto Rico, and 35 foreign countries.

A new lithograph illustrating Saturn Orbit Insertion with information on the Cassini Mission and tour at Saturn has been produced. Copies are available through the Cassini Outreach Office for talks and Cassini-related events.

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.

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