Cassini Significant Event Report

For Week Ending 06/15/01

The most recent spacecraft telemetry was acquired from the Goldstone
tracking station on Tuesday, June 12. The Cassini spacecraft is in an
excellent state of health and is operating normally. Information on the
spacecraft's position and speed can be viewed on the
"Present Position"
web page.

The Visual and Infrared Mapping Spectrometer (VIMS) team successfully
completed four tests of modified flight software (FSW) on the instrument
testbed using the VIMS Ground Support Equipment. Commands from the four
tests were translated into a single set of commands for testing in the
Integration and Test Laboratory (ITL). That testing exercised 73
combinations of parameters while doing regression and new capability
testing. Results were posted on the Telemetry Delivery System for use by
Multimission Image Processing Laboratory (MIPL) during their testing of
VIMS Ground Software in MIPL. Those results are under analysis.

An Imaging Science Subsystem (ISS) flight software glitch related to the
numbering of Instrument Expanded Blocks led to powering down the
instrument as a precautionary measure. A patch will be uploaded as part of
a planned mini-sequence next week.

The ISS team completed analysis of ITL tests with the ISS engineering
models to verify documented IEB load sizes and other behavior. The
results will be influence the current FSW upgrades and will aid in
documenting the ISS response to certain conditions. Modifications and
tests of the new ISS flight software continue on the IO instrument testbed.

The Sequence Team held both a simulation coordination meeting and
simulation walk-through in support of ITL testing for C27, and the tests
executed successfully later in the week. There was also a preliminary
Sequence Change Request approval meeting in support of the C27 Preliminary
Sequence Integration and Validation phase.

An Atmospheres Working Group teleconference was held to discuss the
possible trajectory changes proposed by the Huygens Recovery Task Force.
An Apoapsis Splinter Group teleconference was held to work the integration
issues associated with the apoapsis periods in the Tour.

System Engineering (SE) distributed the Verification and Validation plan
for review pending signature.

The Mission Planning Team delivered the Mission Plan, Rev. M, to the
Cassini Electronic Library, and reviewed trade studies across all Cassini
elements in the Mission Planning forum to organize, prioritize and assign
responsibility for those studies to the appropriate element.

Cassini Uplink Operations supported the X2000/Advanced Technology and
Autonomy for the Future program, providing a large test file for testing
of a new "smart" board X2000 is testing for onboard processing or routing
of command files. X200 needed a file with a large number of Command Link
Transmission Units to check performance, which Cassini was able to supply.

Mission Support & Services Office (MSSO) is working with Cassini Security,
JPL Security, and Building 230 Management in developing a Remedy-based
tool for Space Flight Operations Facility (SFOF) access status. MSSO is
collecting information and requirements from Building 230 Management and
will do the same with JPL Security at a later date. Cassini benefits from
participating in this activity by helping to define and understand the
rules and requirements for SFOS access with the goal of minimizing
building access delays and improve physical security monitoring.

MSSO ACE command procedure has been updated to reflect the Program's
dependence upon institutionally-provided AFS servers. This update
includes an advisory message for users of the system.

The SE team presented the Ground System software inventory and
classification status at the Cassini Design Team meeting. All the Ground
System software classifications have been reviewed, with the majority of
the program classifications accepted and further discussion planned for
the few remaining programs. The required types of documentation for each
classification level was discussed, and initial coordination made for
reviewing the documentation for each program.

Outreach personnel represented Cassini at a workshop in Charleston, South
Carolina that focused on the use of existing and future NASA materials in
classrooms for the visually and hearing impaired. Cassini Outreach also
spoke to 225 students, teachers, and parents participating in the U. S.
Aerospace Challenge rocketry competition in Holland, Michigan.

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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