Cassini Significant Event Report

For Week Ending 05/07/04

The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Tuesday, May 4. The Cassini spacecraft is in an excellent state of health and is operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" web page located at .

Science activities this week included repetitive blocks of imaging with occasional riders, a few Ultraviolet Imaging Spectrograph system scans, and optical navigation (OPNAV) images. Additional on board activities included uplink and successful execution of science mini-sequences, a Reaction Wheel Assembly bias and unload activity, and Visual and Infrared Mapping Spectrometer and Cosmic Dust Analyzer flight software normalization. Normalization involves copying the same versions of flight software to the applicable sections of the SSR and verifying the copies.

On April 29, 2004 the Spacecraft Operations Office completed the in-flight ACS Flight Software (FSW) A8.6.7 uplink and checkout. The A8.6.7 FSW load is needed to support Saturn Orbit Insertion (SOI) activities. Following the update, the C44 background sequence continued nominally with no errors.

Sequence development for S01, the first tour sequence, is nearly complete. This week the Preliminary Sequence Integration and Validation 2 (PSIV) phase was completed and the Final SIV phase begun. Final Waiver Disposition /Sequence Change request meetings were held, and instrument internal expanded block load files for RADAR, Composite Infrared Spectrometer (CIRS), Cassini Plasma Spectrometer (CAPS), Imaging Science Subsystem (ISS), & OPNAV were processed and released. Final sequence approval and uplink of all files to the spacecraft will occur next week.

PSIV1 sequence of events generation (SEG) products for S02 have been released for review. The Simulation Coordination meeting and the Simulation Procedure Review meeting for this sequence were cancelled as no background sequence-specific simulation issues have been identified.

A waiver request approval meeting and official port #2 of the Science Operations Plan (SOP) Implementation process for tour sequences S27 and S28 occurred this week. The delivered sequence products were merged and handed off to the ACS team for a complete end-to-end pointing analysis.

The SOP Implementation process for sequences S29 and S30 was started this week.

The official port for SOP Update of sequence S03 occurred this week. The delivered sequence products were merged and handed off to the ACS team for a complete end-to-end pointing analysis. The Project Briefing and Waiver Disposition Meeting will be held on Wednesday, May 12. The process will be complete on Friday, May 14.

The Spacecraft Team completed the Saturn Orbit Insertion (SOI) End-to-End Dress Rehearsal on May 1, 2004. This rehearsal, using the Integrated Test Lab as the spacecraft, started on April 9, 2004, with the load of the critical sequence to the Solid State Recorders. It was followed by Trajectory Correction Maneuver 21, then the load and activate of the SOI critical sequence. The exercise completed with a nominal SOI execution, followed by a nominal Orbit Trajectory Maneuver 1. On May 3, 2004, the Spacecraft Team started the first of a series of Operation Readiness Tests (ORT) with a spacecraft safing following SOI. The ORTs will continue through May and June.

All teams and offices supported the Cassini NASA Quarterly Review.

In the last week, 1031 ISS images and 15 Visual and Infrared Mapping Spectrometer (VIMS) cubes were returned and distributed, bringing the total number of images acquired since the start of Approach Science up to 5463, and the number of cubes up to 766.

The Multi-Mission Image Processing laboratory sought approval from the Project for a few updates to the current operational system. A set of important upgrades was approved and will be delivered before May 15. The upgrades will improve the reliability of OPNAV image production, correct lab-wide display problems, and reduce hand editing of sequence files.

A delivery coordination meeting for the Remote Terminal Interface Unit (RTIU) software Version 3.1 was held this week. This software simulates the RTIU capability of the Cassini CDS and provides the CDS functionality needed for instrument command and telemetry testing.

A delivery coordination meeting was held for the Cassini Information Management System version 3.1.

The Cassini Speakers' Group hosted another noontime talk at JPL. Presented was "Mysteries of Saturn." This talk and others given by the Cassini speakers group is available to the public. Contact Cassini Outreach at

This week's image release is the last single `eyeful' of Saturn and its rings achievable on approach to the planet. From now until orbit insertion, Saturn and its rings will be larger than the field of view of the narrow angle camera. The image can be viewed on the Cassini web site at

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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