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Cassini Significant Events
for 03/20/03 - 03/26/03

The most recent spacecraft telemetry was acquired from the Canberra
tracking station on Wednesday, March 26. The Cassini spacecraft is in
an excellent state of health and is operating normally.  Information
on the present position and speed of the Cassini spacecraft may be
found on the "Present Position" web page located at
http://saturn.jpl.nasa.gov/operations/present-position.cfm .

The last activity of the Attitude Control Flight Software (FSW)
checkout was a successful Reaction Wheel Assembly friction test.
After that, real time command files were uplinked to set global
variables for the string swap procedure, and memory readouts for the
SSR flight software regions.  These commands enabled Command and Data
Subsystem (CDS) personnel to establish and verify initial conditions
prior to their CDS FSW checkout period.  The CDS checkout began with
activities to load the new version 9 FSW onto the on-line "backup"
CDS string, and a string swap procedure to reset the CDS_A string
executing Version 7.0, and allow the CDS_B String with Version 9.0 to
become the prime CDS string. The swap was successfully completed. The
CDS_A string will continue to execute the Version 7.0 software as a
"hot" backup until Thursday, when CDS_A will also be loaded with
Version 9.0. 

A delivery coordination meeting was held for Version 2.0 Release 1 of
the Remote Terminal Interface Unit (RTIU) software. This delivery was
needed to allow the Ion and Neutral Mass Spectrometer (INMS)
instrument to replay bus traffic from their recent tests in the
Integrated Test Laboratory (ITL) using their RTIU and engineering
model in Michigan. Previously the RTIU had a limit of 1024 commands
in a sequence.  The INMS tests in ITL exceeded that limit so the
number was increased to 2048.  The RTIU software simulates the
Cassini CDS, and provides the CDS functionality needed for testing
instrument commands and data telemetry. 

The Navigation Ancillary Information Facility toolkit, version N0055,
with Cassini components tested, was delivered to the Project Software
Library (PSL).

The Southwest Research Institute in Boulder, Colorado has made the
ISS "pre-commanding" tool software available for download by IO
personnel. User documentation is also included.  This version of the
software has been delivered to the development network side of the
PSL.  After testing by IO, the software will be officially delivered
to the PSL. 

Members of the Navigation team presented contingency missions and
trajectories for the Huygens Probe at the Mission Planning Forum this
week.

Students throughout Los Angeles and Orange Counties have gazed at
Saturn through telescopes in the past two weeks. Members of the
Saturn Observation Campaign have hosted a series of events throughout
Southern California.

The Cassini Program Manager gave two lectures on the Cassini-Huygens
Mission To Saturn, one in Von Karman Auditorium at JPL, and the other
at The Vosloh Forum at Pasadena City College, California.

Cassini is a cooperative project of NASA, the European Space Agency
and the Italian Space Agency. The Jet Propulsion Laboratory, a
division of the California Institute of Technology in Pasadena,
Calif., manages the Cassini mission for NASA's Office of Space
Science, Washington, D.C. 

Cassini Outreach
Cassini Mission to Saturn and Titan
Jet Propulsion Laboratory
California Institute of Technology
National Aeronautics and Space Administration

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