Cassini Significant Event Report

For Week Ending 08/01/03

The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Wednesday, July 30. 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 a Radio and Plasma Wave Science High Frequency Receiver calibration, activation of the Saturn Orbit Insertion (SOI) demonstration critical sequence, a pre-SOI demo ACS configuration activity, and an instrument reconfiguration for the SOI demo. This demo marks the first time that a critical sequence has been executed at a non-critical time, and exercises the last aspects of the flight software installed earlier this year.

The Spacecraft Operations Office reported that the SOI demo critical sequence is currently active on the spacecraft and running in both CDS strings. The first five commands were sent, and all telemetry to this point is per predict. The command loss timer was successfully reset to 9.25 days, as planned. The next critical sequence activity occurs on Monday, August 4th. Data from this activity will be received on the ground at 8:58 A.M. PDT. The spacecraft will be monitored daily for this exercise during each day's Goldstone pass.

The C39 Preliminary Sequence Integration and Validation (PSIV) package has been delivered to the teams for review, and all sequence change requests (SCR) have been submitted. Next week both the preliminary and final sequence approval meetings will be held.

The S14 Science and Sequence Update Process (SSUP) Verification and Validation (V&V) activity concluded this week. Activities performed included generation of the PSIV2 and Final Sequence Integration and Validation (FSIV) products, delivery of final default live movable block sequences and trigger immediate/delayed action programs, generation and release of the FSIV approval package, an FSIV SCR approval meeting, and the final sequence approval meeting. A final wrap-up review meeting has been scheduled for next week.

A wrap-up meeting was held this week for Science Operations Plan implementation of tour sequences S07/S08. The products from this process have now been archived. A kickoff meeting was held for S01/S02 and S03/S04. SO1/S02 is the last use of the 3-port implementation process for tour with S03/S04 being the first use of the 2-port implementation process. Now that V&V activities have concluded, two tour implementation processes will be conducted simultaneously.

A scoping meeting for C42 was held at the Mission Planning Forum. How the sequence will be planned was discussed along with a detailed DSN schedule with information on criticality and flexibility. This latter item was a main point of the discussion, to identify how the project should be delivering planned pass requests to the schedulers to properly equip them to negotiate prior to the SOP Update process.

A delivery coordination meeting was held for Mission Sequence Subsystem (MSS) D9.1. The software has been installed, and is in use by Science Planning in the development of SOP products for S01, 02, 03, and 04. Additionally, the port of MSS D9.1 to Solaris 9 for MSS D10.0 has started and initial progress is good.

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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