Cassini Significant Event Report

For Week Ending 05/04/01

The most recent spacecraft telemetry was acquired from the Goldstone
tracking station on Wednesday May 2. The Cassini spacecraft is in an
excellent state of health and is operating normally. The speed of the
spacecraft can be viewed on the
"Present Position"
web page.

This week marked the end of the Jupiter Science subphase and the beginning
of the Quiet Cruise subphase, which will continue to the end of C32 in
July 2002.

Recent spacecraft activities included the uplink and start of the C26
sequence, automatic repair of the Solid State Recorders (SSRs), two Radio
and Plasma Wave Science (RPWS) High Frequency Receiver (HFR) calibrations,
a high water mark clear, and a Reaction Wheel Assembly unload. Instrument
Expandable Blocks for Cassini Plasma Spectrometer (CAPS), Ultraviolet
Imaging Spectrograph (UVIS), Imaging Science Subsystem (ISS), and RPWS
were uploaded to the spacecraft, and a test of the RPWS trigger was
performed. Additional instrument activities include power-on of the
Composite Infrared Spectrometer (CIRS) followed by a boresight alignment,
and a pattern calibration of the High Gain Antenna (HGA).

Personnel from System Engineering (SE), Instrument Operations (IO),
Spacecraft Office (SCO), Uplink Operations (ULO), Mission Support &
Services Office (MSSO), and Deep Space Mission System (DSMS) supported an
RSS System Assessment Meeting in preparation for the Gravitational Wave
Experiment (GWE) system test. The GWE system test began later in the
week, starting with transmission of two commands to cycle the Ka-band
Translator (KaT) power. The GWE system test will continue into next week,
and is intended to begin characterization of the newly-built Radio Science
instrument and to produce real data products for the GWE investigators
that will allow them to create and refine their analysis processes.

Operations training sessions in support of Cosmic Dust Analyzer (CDA)
personnel from the Max Planck Institut fur Kernphysik, Heidelberg,
Germany, and other Project personnel concluded this week with
presentations by various Cassini Teams. Presentations included a
Spacecraft, Planet, Instruments, C-matrix, and Events kernels (SPICE)
tutorial by the Cassini SPICE Development Team and a demonstration and
hands-on session with the Science Opportunity Analyzer tool being
developed by Telecommunications and Mission Operations Directorate (TMOD).

The ground system development team held a review of development schedules
to ensure understanding of priorities and drivers and alignment of
schedule dates for GWE, Space Science, Approach Science and Tour.

The Mission Planning team reviewed the high-level timeline of events for
late cruise and early Tour in the Mission Planning Forum, with specific
attention on events required for readiness for Saturn Orbit Insertion
(SOI), Probe Relay, and the Titan-3 flyby. Additionally, Mission Planning
personnel completed element-specific reviews of Mission Plan Guidelines &
Constraints and presented Mission Planning Roles & Responsibilities at the
Cassini Design Team meeting in a "Question & Answer" format.

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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