Cassini Significant Event Report

For Week Ending 06/01/01

The most recent spacecraft telemetry was acquired from the Goldstone
tracking station Tuesday May 29. 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.

Recent spacecraft activities included a Radio and Plasma Wave Science
(RPWS) High Frequency Receiver (HFR) calibration, a high water mark clear,
and an Attitude and Articulation Control Subsystem (AACS) Reaction Wheel
Assembly (RWA) Slow Time Memory Readout. The D7.4 modules file was
successfully uplinked to the spacecraft with confirmation that all four
module programs registered as expected. Periodic Instrument Maintenance
(PIM) operations were performed for the Ultraviolet Imaging Spectrograph
(UVIS), Imaging Science Subsystem (ISS), Composite Infrared Spectrometer
(CIRS), Visual and Infrared Mapping Spectrometer (VIMS), and RADAR
instruments, with initial indications showing nominal execution. ISS
performed both a photometric calibration and a dark frames activity.
Additionally, AACS performed a Reaction Control Subsystem (RCS) Catbed
Heater test to verify an AACS thermal heating model. Initial results show
good agreement.

The Radio Science (RS) Ka-Band Translator (KaT) was powered-on for Solar
Conjunction Experiment (SCE) testing, after having been off since the
first Gravitational Wave Experiment (GWE) system test completed earlier
this month. While previous testing had developed a successful procedure to
achieve and maintain the KaT at a good operating state, telemetry during
recent activities with the KaT and S-Band Translator (SBT) on
simultaneously showed that the KaT was not operating properly with the SBT
powered-on. The KaT was power-cycled according to the new procedure but
still failed to operate properly. The RS team powered off the SBT and then
allowed the Radio Frequency Instrument Subsystem bay to reach a stable
thermal point. The KaT was power-cycled again, after which it attained a
good operating state. The KaT will remain powered-on for the duration of
the SCE testing, and the KaT behavior studied further

The Sequence Virtual Team (SVT) completed the Subsequence Generation Phase
for C27 Sequence development with all instrument teams and engineering
subsystems delivering their populated command subsequences. The SVT has
begun the Preliminary Sequence Integration and Validation phase for C27
Sequence development, and released the integrated sequence late this week.

The Mission Support & Services Office (MSSO) Verification and Validation
(V&V) test network is up and running.

A "Cassini Export Compliance and Security Requirements" meeting was held.
This meeting was co-produced by the Office of Legislative and
International Affairs and MSSO/Computer Security. The primary objective of
the meeting was to explain the current U.S. Export rules, regulations, and
security requirements including International Traffic in Arms Regulation
(ITAR) and Export Administration Regulations (EAR), and how those
regulations affect the Cassini Flight Team specifically and JPL employees,
US nationals, and foreign nationals in general.

The Project Science Group (PSG) meeting agenda was released for the
upcoming meeting to be held in Oxford, England late June.

The Uplink Operations (ULO) team distributed MSS D7.6 Module Functionality
Review materials in support of a pending review. ULO also presented a
proposal for the first delivery of the Solid State Recorder (SSR)
Management Tool (SMT), which includes a summary of initial requirements to
be met and capabilities to be provided by the SMT.

System Engineering (SE) held a preliminary Delivery Coordination Meeting
(DCM) to ensure that the ULO/MSS delivery of the Science Opportunity
Analyzer tool is ready to be installed on the OPSNET and on the Science
Operations and Planning Computers (SOPCs). Issues regarding ITAR, testing
and configuration were discussed; everything was found to be in order and
the final DCM is scheduled for later this week.

SE also signed three Software Interface Specifications (SISs) to support
the Maneuver Automation Tool. While each SIS had already existed, some
minor modifications and additions were required.

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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