Cassini Significant Event Report

For Week Ending 07/16/04

The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Wednesday, July 14. 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 .

Cassini exited the Solar Conjunction period this week. Telecommunications performance was limited as expected due to the position of the Sun between the spacecraft and Earth. Full communications capability was restored once a 2-degree Sun-Earth-Probe separation angle was achieved. After conjunction all instruments were once again configured for science acquisition.

On or about July 13, Cassini exited Saturn's magnetosphere and the Magnetospheric and Plasma Science instruments began to monitor the solar wind. The unique geometry of this period of high altitude and phase angles of ~100 degrees will allow the Ultraviolet Imaging Spectrograph to simultaneously measure Saturn's aurora and magnetosphere.

On-board activities this week included a reaction wheel assembly bias, uplink of a ram flight software patch and table load for the Cassini Plasma Spectrometer, Probe Checkout (PCO) #14, and a test of the Probe Mission Timer Unit (MTU). This is the first checkout of the probe since Saturn Orbit Insertion. All probe instruments and the MTU are functioning properly. In preparation for probe release and relay, the checkout was utilized by members of the ground system to practice the generation of 30 minute IDRs and the monitoring of the data flow to the Huygens Probe Operations Center.

Members of the Cosmic Dust Analyzer (CDA) instrument team escorted an engineering model of the instrument to JPL where it was connected to a test bed in the Integrated Test Laboratory for flight software testing. Next week the ITL will resume Probe Relay testing.

Official port#2 of Science Operations Plan (SOP) Implementation of tour sequences S31/S32 occurred this week. The products were merged and delivered to ACS for end-to-end pointing analysis. Preliminary port#1 of SOP Implementation of tour sequences S33/S34 also occurred this week. The files were merged and a report was delivered identifying issues to be worked.

The S05 SOP Update process began this week, and an assessment meeting to review requested changes to S07 was held as part of the Aftermarket process. Initially it appears that all requested changes can fit within available resources. The Target Working Teams and Orbiter Science Teams will be reviewing the requests over the next two weeks and provide their recommendations at the decision meeting scheduled for July 27.

The Huygens Probe Mission Risk Review was held on Wednesday, July 14. This was an external review convened to assess the risks and risk mitigation measures associated with the probe mission. The board was comprised of independent reviewers from JPL, other NASA centers, and industry. The review was very successful with positive closing comments from the board.

All teams and offices supported this month's Cassini monthly management review.

A Software Review/Certification Requirements meeting was held for CDA flight software (FSW) version 9.2.4 Two bug fixes were previously approved for this "patch" delivery. The next full delivery of this FSW is scheduled for Dec 2004, with uplink planned for post-Probe mission.

For the latest images and more information about the Cassini-Huygens mission, visit and