Cassini Significant Event Report

For Week Ending 05/30/03

The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Wednesday, May 28. 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 the Engine Gimbal Actuator exercise and Backup ALF Injection Loader maintenance portions of ACS Periodic Engineering Maintenance, clearing of the ACS high-water marks, and participation in a DSS-25/ DSS-26 array demonstration.

Instrument activities included Radio and Plasma Wave Science (RPWS) high rate observations, a high rate Magnetometer Subsystem Science Calibration Subsystem calibration, and uplink and execution of commands to perform normalization of instrument flight software for RPWS, RADAR, and Cosmic Dust Analyzer. DSS-43 was declared red due to a hardware failure on Saturday, May 24. As a result, data from the Composite Infrared Spectrometer (CIRS) flight software checkout and most of the CIRS Remote Sensing Pallet heater test to be played back over that pass was lost. A plan is being worked to re-run the flight software checkout and play back the data. There is no plan to recover the heater test.

The Radio Science Subsystem quiet test originally planned for C37, and lost as a result of the May spacecraft safing event, has been rescheduled to execute during C39.

The Multi-mission Image Processing Laboratory processed and delivered 57 Imaging Science Subsystem (ISS) wide-angle camera dark frame images from the C37 sequence. ISS has no more scheduled science activities until C39.

Five manuscripts based on ISS observations taken during the Jupiter flyby have been submitted for publication. One paper was submitted to the Astronomical Journal, three to a special issue of Icarus, and one a draft version of a soon-to-be-submitted paper to Icarus.

The official port#1 products for Science Operations Plan implementation of tour sequences S7/S8 were delivered to Science Planning. The products were then merged and handed off to ACS for end-to-end-pointing validation.

Target Working Teams and Orbiter Science Teams have delivered integrated products for Revs 39-46. The Science and Sequence Update Process (SSUP) portion of the Uplink Verification & Validation (V&V) activity kicked off this week. The Sequence Team (ST) met to review the ten-week schedule to be used to create the final uplinkable sequence for the V&V activity, and reviewed the actions remaining after the Science Operations Plan Update (SOP U/D) V&V. The ST lead accessed the merged products produced during the SOP U/D V&V activity, and split out and distributed the subsequences for each team. The teams have begun updating their products per the actions listed in the SOP U/D to SSUP hand-off package.

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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