Cassini Significant Event Report

For Week Ending 09/15/00

The most recent spacecraft telemetry was acquired from the Madrid tracking
station on Wednesday, 9/13. The Cassini spacecraft is in an excellent
state of health and is operating normally. The speed of the spacecraft can be viewed on the "Where is Cassini Now?" web page.

The Cruise 21 sequence concluded this week with real time commands sent to
the spacecraft to optimize the dust stream measurements for the Cosmic Dust
Analyzer (CDA), to power off the Imaging Science Subsystem (ISS) Narrow Angle
Camera (NAC) & Wide Angle Camera (WAC), and to turn ISS replacement heaters on.
The Final Sequence Integration & Validation (SIV) Approval Meeting was held
for Cruise 22. The sequence was then uplinked, registered and activated.

C22 is the first of four sequences containing science activities
supporting the Jupiter flyby. It contains the first instance of
"repeating template" observations. The template is five days in duration,
contains a specific set of observations, and will repeat continuously
until ten days into the C23 sequence when a change in observations is
desired. A total of four different templates has been designed for the
Jupiter period. Templates will be used throughout the Jupiter subphase
except for approximately Jupiter -25 days to +22 days. At that time
templates are suspended and unique observations will occur. Templates
were implemented due to the need for simplified operations during
Cassini's cruise phase.

Activities for the start of C22 included setting of the off sun time
constraint, reaction wheel desaturation, loading of a new body vector, ISS
power on, replacement heaters off, and IEB load, and the start of Cassini
Plasma Spectrometer (CAPS), Cosmic Dust Analyzer (CDA), and Ultraviolet
Imaging Spectrometer (UVIS) Flight Software (FSW) loads. The FSW load
activity will continue into next week.

Cruise 23 has completed the subsequence generation phase with all
instrument teams and the Spacecraft Office supplying their detailed
command requests for the background sequence. C23 is now in the Sequence
Integration and Validation Phase, where all subsequences will be
integrated together to produce the official background sequence.

The CDA experimenters from the Max-Planck-Institut fur Kernphysic in
Heidelbeg, Germany, brought the engineering model of their instrument to
the Integration and Test Laboratory (ITL) at JPL for detailed flight
software testing. The integration of the instrument into the lab was
completed and testing is underway.

The Spacecraft Operations Office held a bimonthly Flight Software and
Critical Sequence status review.

All user acceptance testing of TC&DM V25.2 is complete and all reports are
finished. This delivery includes telemetry (TLM), command (CMD) and the
Distributed Object Manager (DOM). A Delivery Coordination Meeting (DCM)
for installation has been held. The plan is to install on the SUNs first
and then proceed with HPs.

Invitations have gone out for two upcoming educator workshops: "Millennium
Flyby Science" and "Radio Astronomy at Jupiter". Registration will
continue for both workshops through Friday 6 October 2000. It is
anticipated that both will be full prior to that date. More information
may be obtained via the Cassini Educator Hotline at (818) 393-5683 or an
e-mail sent to

The "Millennium Flyby Travel Guide" has been released by Document Review
and will be ready for web posting and printing later this month. The Travel
Guide will be available on the Cassini Millennium Flyby web site at
HREF=""> .

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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