Cassini Significant Event Report

For Week Ending 06/22/01

The most recent spacecraft telemetry was acquired from the Goldstone
tracking station on Wednesday, June 20. 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.


Recent spacecraft activities included two clears of the Attitude and
Articulation Control Subsystem (AACS) high water mark, a Magnetospheric
Imaging Instrument (MIMI) Low Energy Magnetospheric Measurement Subsystem
exercise, and a Radio and Plasma Wave Science (RPWS) high frequency
receiver calibration. A Periodic Engineering Maintenance activity was also
conducted, which included exercising the Engine Gimbal Assembly and
routine maintenance on both the Reaction Wheel Assembly #4 and Backup ALF
Injector Loader. Additionally, a test of the Huygens Probe S-Band
transmitter was performed, which included checking performance of both the
A and B chains of the Probe Support Avionics.


The Sequence Virtual Team has begun preparations for sequence testing in
the Integration Test Laboratory in support of the C27 Probe mute test.


The Cassini Program Science Group began a week-long meeting in Oxford,
England. In addition to science discipline working group meetings and
instrument reports, topics of discussion include progress of the Huygens
Recovery Task Force and Science Operations Plan development.


The Mission Planning team began a detailed assessment of Titan flyby
minimum altitudes. Use of reaction wheel and thruster control, and the
resulting hydrazine consumption are among the topics to be considered.



Additional information about Cassini-Huygens is online at http://saturn.jpl.nasa.gov.


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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