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Cassini Significant Events
for 08/26/04 - 08/31/04

The most recent spacecraft telemetry was acquired from the Madrid
tracking station on Tuesday, August 31. The Cassini spacecraft is in
an excellent state of health and is operating normally. Information
on the present position and speed of the Cassini spacecraft may be
found on the "Present Position" web page located at
http://saturn.jpl.nasa.gov/operations/present-position.cfm

Last week Cassini passed apoapsis, the farthest point from Saturn in
its orbit, and in this case, in the entire tour. It also marked the
transition between Rev 0 and Rev A - Rev being another term for
orbit - and marks the start of Cassini's approach to Titan for the
Titan-a encounter in October. At its present position, Cassini is
outside Saturn's magnetosphere. From this vantage point the
Magnetospheric and Plasma Science (MAPS) instruments continued their
campaign to study the influence of the solar wind on Saturn's
aurora. The combination of this large distance and the quality of
the imaging subsystem allows an opportunity to obtain mosaics and
movies over large areas that will be used to study storms and
dynamics in Saturn's atmosphere.

This week the optical remote sensing (ORS) instruments scanned
Saturn's south pole, obtained ultraviolet mosaics of Saturn's
magnetosphere, and observed Saturn's aurora. The imaging cameras
obtained mosaics and movies of the rings and Saturn's south pole,
and the Magnetospheric Imaging Instrument (MIMI) imaged the
magnetosphere and observed the solar wind and pickup ions.

Additional activities included uplink of a file to activate an
internal sequence for the Cosmic Dust Analyzer, and a time-of-flight
unit tweak for the Cassini Plasma Spectrometer to obtain higher
resolution data during their upcoming calibration.

Spacecraft Operations Office activities this week included a
reaction wheel assembly friction test on board the spacecraft, and a
test of Orbit Trim Maneuver 003 (OTM) in the Integrated Test
Laboratory. The results from the friction test are being analyzed
currently. Friction tests are performed every three months on the
prime wheels 1,2 and 4 to trend their performance.
OTM-3 will be tested twice, once using the Reaction Control
Subsystem and the second time using the main engine. The benefit of
using the main engine for such a short burn - approximately 3
seconds - is that it allows the program to conserve the hydrazine
propellant.

The Section 312 Navigation Advisory Group conducted a review of the
Project's planning and preparation for the Huygens Probe mission
activities. The board report is not available yet, but comments
during the course of the review were generally favorable.

The sub-sequence generation products were delivered to the program
file repository in support of sequence development for S05. In
addition, a meeting was held to discuss simulation requirements for
Titan-a Integrated Test Laboratory testing.

The Mission Sequence Subsystem (MSS) team released MSS D11 baseline
plans for Project review at a Cassini Design Team meeting this
week. At the same time, a discussion was held for plans and
proposed features for MSS D10.3.2, D10.3.3 and D10.4 deliveries
prior to the Probe Mission and leading up to the D11 delivery in
April of next year.

For the most recent Cassini information, press releases, and images,
go to http://saturn.jpl.nasa.gov

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. The Jet
Propulsion Laboratory, a division of the California Institute of
Technology in Pasadena, manages the Cassini-Huygens mission for
NASA's Science Mission Directorate, Washington, D.C. JPL designed,
developed and assembled the Cassini orbiter.