Cassini Significant Event Report

For Week Ending 06/23/00

The most recent spacecraft telemetry was acquired from the Madrid
tracking station on Wednesday, 06/21. The Cassini spacecraft is in an
excellent state of health and is operating as expected. The speed of the spacecraft can be viewed on the "Where is Cassini Now?" web page.

Maintenance of the Visual and Infrared Mapping Spectrometer (VIMS)
instrument was accomplished by turning on the Infrared Optics
decontamination heaters for a 24 hour period following Trajectory
Correction Maneuver-14. Updated flight software and Instrument Expanded
Blocks (IEBs) for the Cassini Plasma Spectrometer (CAPS) and VIMS
instruments were loaded on board. CAPS actuator and flight software
checkouts were performed. VIMS dark frame collection, internal
calibration, and flight software checkout were begun. The Attitude and
Articulation Control Subsystem (AACS) completed a reaction wheel unload.

Development for the Cruise 21 background sequence continues, C21 is
currently in the Sequence Integration and Validation (SI&V) phase.

A review of the Tour Phase requirements and design of the Spacecraft
Office was conducted. Feedback from the review board was positive. This
is the first of a series of requirements and design reviews at the Office
and Team level to be conducted through September.

Mission Planning has begun the formal coordination of engineering and
science activities in the Saturn Orbit Insertion (SOI) and Probe Relay
critical sequences.

An Orbiter Science Operations Working Team (OSOWT) telecon was held to
continue the science integration process for the Jupiter Subphase. This
telecon finalized the resolution of conflicts that existed in Phase F
(Jupiter closest approach +15d to JCA +72d), and began the science
integration process for the C25 portion of the Jupiter Subphase (JCA +72
days to JCA +120 days).

Version D7.2 of the Mission Sequence System (MSS) software was approved
for delivery to operations. Installation has begun and will completed by
the end of the week. Major changes in this delivery include updates to
the Pointing Design Tool, engineering and science sequence modules, the
MSS Tool Launcher, and a number of flight rules.

The Cassini web site has been added to the space link directory on the
Universe Today web site. Universe Today provides space exploration and
astronomy news in an overview format with links to sites where more detail
may be found. The goal of this site is to build a comprehensive directory
of space links for educators, students, and space buffs. The Cassini link
may be found by going to and clicking on
"Space Links." After selecting "Missions", the Cassini Home Page can be
selected from the alphabetical listing.

Representatives from the web site videotaped presentations
made by Cassini Radio Science team members. The URL is .

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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