Cassini Significant Events
for 01/21/09 - 01/27/09

The most recent spacecraft telemetry was acquired on Jan. 27 from the
Deep Space Network tracking complex at Goldstone, California.  The
Cassini spacecraft is in an excellent state of health. Information on
the present position and speed of the Cassini spacecraft may be found
on the "Present Position" page at:
http://saturn.jpl.nasa.gov/operations/present-position.cfm.


Wednesday, Jan. 21 (DOY 021):

Saturn is once again visible in the evening sky and can be found in
the constellation Leo from now through September. You'll easily spot
the pale golden planet rising in the east-northeast by mid-evening
towards the end of the January. Though the ring tilt narrows to
edge-on in September, Saturn will be so close to the Sun then that it
will offer an unsatisfactory viewing opportunity. Be sure to look at
Saturn's narrow ring this month!


Thursday, Jan. 22 (DOY 022):

Orbit Trim Maneuver (OTM) #180 was uplinked to the spacecraft today.
The files were sent a day early to allow two opportunities for uplink
to ensure receipt on the spacecraft prior to the primary maneuver
pass on Jan. 23, and avoid heavy penalties associated with dropping
to the backup maneuver window. As part of normal maintenance,
additional files were also sent to clear the CDS and System Fault
Protection error logs.

A kickoff meeting was held today for a Live Inertial Vector
Propagator update due to execute on DOY-033. Originally planned for
Rhea vectors alone, analysis showed that a Saturn update might be
needed along with a Titan update to preserve a cloud observation. The
scientists have determined that all updates are necessary, so the
window has been expanded to include DOY-031 to DOY-034.  File
generation and validation will proceed at this time with uplink to
the spacecraft planned for a week from today.

Friday, Jan. 23 (DOY 023):

Orbit Trim Maneuver (OTM) #180 - the 100th main engine maneuver to be
performed by the spacecraft since launch - was performed today.  This
is the periapsis maneuver setting up for the Titan 50 encounter on
Feb. 7.  The main engine burn began at 9:00 PM PST. Telemetry
immediately after the maneuver showed the burn duration was 27.8
seconds, giving a delta-V of 4.67 m/s. All subsystems reported
nominal performance after the maneuver.  Cassini Telecom reported
high winds at the DSN complex in Madrid of up to 63 km/hr during the
maneuver. High winds can adversely affect antenna pointing accuracy
and also impact antenna dish shape to a limited extent. However, no
adverse effects have been detected in the Cassini data.

Monday, Jan. 26 (DOY 026):

A weeklong series of discussions and presentations began today as
Cassini scientists and flight team members gathered for the 47th
meeting of the Project Science Group.

Tuesday, Jan. 27 (DOY 027):

All teams provided files today for the S51 Port 1 delivery as part of
the Science Operations Plan process.

Currently the Saturnian poles are experiencing major changes in
seasonal lighting, with the north polar region experiencing sunlight
for the first time in over a decade and the south polar region about
to enter over a decade of polar winter. Studies of these regions over
the next few years hope to reveal changes in Saturn's meteorology and
circulation produced by such seasonal changes, including solar heat
deposition. In addition, images of the north pole -where sunlight is
just beginning to illuminate features - will reveal the structure and
microphysical nature of upper tropospheric clouds that help form the
bizarre hexagonal feature there.

A concerted effort by several Cassini remote sensing instruments - in
particular, Imaging Science, Ultraviolet Imaging Spectrograph, and
Visual and Infrared Mapping Spectrometer - will enable the
multifaceted nature of polar aurorae to be revealed. All three
instruments will image the aurorae over a variety of wavelengths,
thus quantitatively mapping their power over the polar regions.
Multiple images acquired regularly over short periods of time
spanning minutes to hours will characterize the transient nature of
auroral phenomena. Correlations of auroral activity with underlying
hazes will help our understanding of the role aurorae play in
generating polar hazes and clouds.

Visit the JPL Cassini home page for more information about the
Cassini Project: http://saturn.jpl.nasa.gov/>
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