Cassini Significant Event Report

For Week Ending 03/16/00

The most recent spacecraft telemetry data was acquired from the Goldstone
tracking station on Wednesday, 03/15. The Cassini spacecraft is in an
excellent state of health and is operating normally. The speed of the spacecraft can be viewed on the "Where is Cassini Now?" web page.

The new Attitude Control Flight Software checkout continued this week. On
Thursday, March 9, a mini-sequence to execute the RWA exercise from the
Periodic Engineering Maintenance activity was uplinked and executed
nominally. The transition from thruster control to reaction wheel control
was executed via real time commands on Saturday, March 11. This was the
first time in flight that attitude control has been managed by the reaction
wheels. A high gain antenna calibration, using the reaction wheels, was
performed on Sunday, March 12. Attitude control via the reaction wheels
is nominal and all measurements indicate excellent performance. Momentum
buildup has been per predict and a momentum desaturation maneuver was
performed on Wednesday, March 15. The checkout continues throughout this
week with larger commanded turns using both the wheels and thrusters.

Final Activity Plan products have been published for the C20 sequence,
closing out the Sequence Strategy Phase for C20 development. The
Subsequence Generation Phase for C20 has begun with the release of all the
subsequence products for the instruments/subsystems to populate with

Trajectory information to address a trade between the fields and particles
instruments, radio science and the optical remote sensing instruments for
the first and second Enceladus flybys in the tour has been generated.

A software requirements and certification review (SRCR) was held for the
Command and Data System flight software versions V7.0-009. This is the
final version scheduled for uplink to the spacecraft on March 25-26.

An SRCR was also held for UVIS and RPWS instrument flight software.
Instrument representatives presented a summary of the changes to their FSW,
the tests conducted, and verification that their FSW is ready for ITL
testing and to be loaded onto the spacecraft.

MIMI and VIMS flight software and associated development files have been
delivered and loaded into the Project Software Library. The FSW SRCR for
these instruments is scheduled for next week.

An all day Cassini budget retreat was held this week to address funding
issues for FY01.

Cassini personnel have concluded their weekly polling/reporting activity
in support of NASA Y2K compliance.

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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