Cassini Significant Event Report

For Week Ending 05/23/03

The Cassini flight team successfully restarted the C37 background sequence on Saturday, May 17 after last week's safing event. Normal sequencing resumed with Visual and Infrared Mapping Spectrometer (VIMS) and Imaging Science Subsystem (ISS) star calibrations. The spacecraft engineering subsystems and instruments are performing nominally. The instrument calibrations that did not occur due to spacecraft safing will be rescheduled for a subsequent sequence. Information on the spacecraft's position and speed can be viewed on the "Present Position" web page.

Additional activities performed this week included Radio and Plasma Wave Science High Frequency Receiver Calibrations, a Ultraviolet Imaging Spectrograph (UVIS) raster observation, a reaction wheel assembly friction test, an attitude control high water mark clear, and the successful uplink of the Composite Infrared Spectrometer (CIRS) instrument flight software (FSW) version 2.0.1, and an CIRS FSW checkout mini-sequence. The checkout mini-sequence will execute next week.

Due to concerns over the performance of reaction wheel three, the project has decided not to perform the thirty day solar conjunction experiment under reaction wheel control. The solar corona portions of the experiment using K-band will continue over the Goldstone tracking station as planned using the thrusters for attitude control.

ISS acquired 24 images during a point and stare calibration image activity with VIMS riding along. ISS also acquired 232 images, including dark frames and two by two mosaics, during a photometric calibration of the star Vega.

The first preliminary delivery port for Science Operations Plan Integration products for tour sequences S07 / S08 occurred this week, with the first official input port scheduled for next week.

The CIRS instrument team has provided the Planetary Data System atmospheres node with a sample volume containing Jupiter data. The volume is under peer review, and is also being reviewed by members of the Cassini/Huygens Project Science Group. The review should be completed within four weeks. CIRS is the second instrument team, following the Radio Science Subsystem to produce a volume for peer review

Program members from various teams and offices are attending the thirty-first Project Science Group meeting in Venice, Italy this week.

Uplink Operations personnel gave a demonstration of the Cassini Information Management System (CIMS) to the Section 314 technologist. The intent of the demonstration was to initiate exploration of CIMS potential for future use in the Multi-Mission Software set.

Approximately 25,000 people attended the JPL Open house last weekend. Cassini personnel staffed a booth where they could answer questions regarding the program. In addition, members of the Outreach Team debuted a beta-test version of "Ring World", the project's planetarium show. Response from the public was extremely enthusiastic.

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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