Cassini Significant Event Report

For Week Ending 02/02/01

The most recent spacecraft telemetry was acquired from the Goldstone
tracking station on Wednesday, January 31. 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.

Phase F Post Jupiter Activities continued this week with Imaging Science
Subsystem (ISS) atmosphere observations, and Magnetospheric Imaging Instrument
(MIMI) Magnetosphere observations, uplink and execution of the Cassini
Plasma Spectrometer (CAPS) memory readout (MRO) mini-sequence, and uplink
of a MIMI flight software patch. The MIMI patch went in as expected, and
should reduce susceptibility to motor control stack overflows. Additional
commanding included clearing of the AACS High Water Marks, an AACS
Reaction Wheel Assembly (RWA) momentum unload, and an RWA slow time MRO.

The Probe Relay Test mini-sequence was uplinked along with additional
commands to power off CAPS and the RSS Ka-band transmitter. The remaining
instruments were placed in "sleep" for the duration of the test period.
The test began execution Wednesday with data from the first test
downlinked late in the day. The activity is proceeding well and will
continue to run over the next 4 days.

The Cassini Instrument Operations (IO) Team and the Multi Mission Image
Processing Laboratory have produced and delivered 21,987 ISS images -
15,054 from the NAC and 6,933 from the Wide Angle Camera - and 4,689
Visual and Infrared Mapping Spectrometer (VIMS) cubes since Jupiter
encounter began. No additional cubes were processed this past week. A
software upgrade is expected soon that will enhance processing of the 2X2

Analyses continue on the Jupiter data received earlier this month. The
data show preliminary detection of the synchrotron emission of high-energy
electrons in the Jovian radiation belts. The Cassini RADAR Jupiter
Synchrotron experiment was performed jointly with the Very Large Array
(VLA), the Deep Space Network (DSN), the Goldstone-Apple Valley Radio
Telescopes and their students, and with Cassini Outreach. These are the
first data obtained of the Jupiter synchrotron emission in the two-cm
wavelength range. This wavelength has been unattainable from earth-based
telescopes. The Cassini radiometer data will tie down the previously
unexplored upper limit when combined with our ground based partners'
synchrotron emission data acquired in the 20 cm and 90 cm wavelength
ranges. These combined data will be used to create a new map of the
Jovian energetic particle distribution within Jupiter's radiation belts.

Analyses of the RADAR Jupiter data have shown that the radiometer is
proving to be an extremely sensitive instrument. This information is
being factored into Tour planning activities and the addition of more
RADAR/radiometer targets of opportunity such as Saturn's disk and the

Last week the Ka-band signal on Cassini was tracked for the first time
using the Monopulse Tracking System at Deep Space Station 25 . Monopulse
is an enabling system for the Gravitational Wave Experiment to be
conducted in November of this year. The entire DSS-25 Cassini Radio
Science Upgrade Task will be delivered in mid-April 2001.

A preliminary Sequence Integration & Validation (SIV) Sequence Change
Request (SCR) approval meeting was held this week for C25. Sequence
change requests pertaining to the update of the DSN allocation file were

All Cassini Teams supported an Independent Annual Review (IAR) held at
JPL. Topics included a Program Overview, Jupiter Science Presentation,
and presentations by Science, Development, System Engineering, Mission
Assurance, Spacecraft Operations Office, Science & Uplink Office, and the
Mission Support & Services Office.

The Program Science Group meeting held at JPL concluded this week.
Working groups met for the Huygens Science Working Team, RADAR,
Atmospheres, Magnetometer Subsystem (MAG), Magnetospheric and Plasma
Science (MAPS), Rings, and Surfaces. Presentations at the plenary sessions
included a Cassini Program Status Report, Huygens Reports including Flight
Operations, Uplink Test, and Recovery Task Force, SCO Activities report,
Jupiter Lessons Learned, SOAP Movie-Tour Highlights, Tour Safety Hazards,
Science Operations Plan Development, Tool Development/Modules, Power
Modes/Ops Modes, Radiator Flight Rule Status, SOST Status Report, TOST
Status Report, Publications & Meetings Status Reports, presentation of
Rings, Atmospheres, Surfaces and MAPS Working Group Reports, and
instrument reports featuring Jupiter results

At the conclusion of the PSG, a Future Titan Missions Workshop was held.

Concurrent with the PSG, training continued providing visiting Cassini
instrument personnel and JPL resident Flight Team Members the opportunity
to view presentations on a number of topics. Science and Uplink Office
(SAUL) personnel gave hands-on demonstrations of the Cassini Information
Management System (CIMS), Pointing Design Tool (PDT), and Science
Opportunity Analyzer (SOA). Instrument Operations held a session on the
Planetary Data System and plans for data archiving and System Engineering
and Instrument Operations covered how the Cassini Program tracks and
responds to anomalies. The Telecommunications and Mission Operations
Directorate (TMOD) provided a trainer to cover the Mission Ground Data

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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