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Cassini Significant Events
for 05/08/03 - 05/14/03

The Cassini Spacecraft executed a system safing response Sunday
evening at about 21:30 PDT. The safing response was initiated by the
attitude control system, and was due to a call to an invalid pointing
vector in the C37 background sequence. All spacecraft fault
protection responses including the high gain antenna recovery
algorithm were as expected and the spacecraft is currently in its
nominal safing state communicating at a downlink rate of 1896 bps.
All subsystem telemetry is nominal. 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 C37 background sequence was automatically cancelled as part of
the safing response. The period of the sequence affected contained a
series of instrument calibrations performed on reaction wheels, star
observations, and imaging of Saturn. The instruments involved were
the Composite InfraRed Spectrometer, Visual and Infrared Mapping
Spectrometer, Ultraviolet Imaging Spectrograph, Imaging Science
Subsystem, RADAR, and the Radio Science Subsystem (RSS).  RSS
periodic instrument maintenance was recovered by sending real-time
commands to power on/off the necessary hardware.

The spacecraft and sequencing teams have developed a recovery plan
for instrument power on, flight software loads, and Instrument
Expanded Block (IEB) loads.  The background sequence will be
restarted on Saturday. Prior to safing, activities performed included
clearing of the ACS high water marks, uplink of the RADAR IEB
trigger, execution of the VIMS IEB load, Radio and Plasma Wave
Science High Frequency Receiver calibration, and transition to
Reaction Wheel Assembly control. 

A kick off meeting was held this week for the subsequence generation
phase of C38.  Stripped sequence files have been provided to the
participating instrument teams.

A wrap up review was held for the S14 Science Operations Plan (SOP)
Update Verification and Validation (V&V) activity. The meeting
presented a summary of the entire SOP U/D V&V in preparation for
Science and Sequence Update Process (SSUP) V&V.  Due to the conflicts
of resources for C37, C38, S07/S08, and the Project Science Group
(PSG) meeting to be held next week, it has been decided to slip the
SSUP V&V kick-off to Tuesday, May 27th.

The Spacecraft Operations Office held a risk review on the upcoming
Saturn Orbit Insertion (SOI) demonstration. The board, which
consisted of independent reviewers familiar with the Cassini
spacecraft and software, was chartered with examining the upcoming
activity to determine if the program was taking any untoward risks.
The board concluded that the demonstration design achieved an
appropriate balance between risk, and the goals of validating
portions of the SOI activity. 

A delivery coordination meeting (DCM) was held for Mission Sequence
Subsystem (MSS) version D9.0.2.

This patch fixes a problem with how Pointing Design Tool users are
able to see the graphics display.  MSS software testing has been
revised to catch future occurrences of this type of problem.  An
additional DCM was held for a Telemetry, Tracking, Command & Data
Management patch "QPF" for real-time telemetry (TLM) servers to keep
Science Operations and Planning Computer TLM queries from timing out.
RSS completed an analysis resulting in a greatly improved program for
the X- & Ka-Band Boresight Vector Determination Software Suite.
Modifications include a new graphical user interface, newly created
estimates of the boresight vector error variance, and a new automated
ability to remove a newly discovered source of systematic error.

Outreach gave presentations on Galileo and Cassini to 3rd through 8th
grade students at Union Mesa School in Somis, California. The talks
were part of the school's "Space Exploration" day.  The one-day
series of talks was attended by 392 students and teachers.

Cassini Outreach is in the midst of their annual invitation to
project members to join the Cassini Speakers Group. Interested
project members should contact the Outreach Office.

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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