From: Jet Propulsion Laboratory
Posted: Friday, December 19, 2008
The most recent spacecraft telemetry was acquired on Dec. 16 from the Deep Space Network tracking complex at Madrid, Spain. The Cassini spacecraft is in an excellent state of health and all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at:
Wednesday, Dec. 10 (DOY 345):
An encounter strategy meeting was held today to cover the period between Dec. 21 and Feb. 7, Titan flybys T49 and T50, and maneuvers 179-181.
Today Imaging Science (ISS) performed a 6.5 hour azimuthal scan of a 1.47 Rs ringlet. Following the scan ISS undertook a 13-hour medium resolution observation of the F ring to produce a movie with the Composite Infrared Spectrometer (CIRS) and Visual and Infrared Mapping Spectrometer (VIMS) riding along.
Thursday, Dec. 11 (DOY 346):
On Thursday, December 11, the Titan Orbiter Science Team (TOST) hosted a meeting to integrate the "caboose" TOST segments. These are one to two day periods added to some Extended Mission TOST segments - Titan 63-66 and Titan 68-70 - after the "main" downlink in order to accommodate Titan monitoring. The plan is to gather inputs from the instrument teams for all caboose segments at a single meeting. Following that, the TOST lead responsible for that segment will act as a block lead for the associated caboose(s), and will generate a proposed timeline for review.
Friday, Dec. 12 (DOY 347):
Two meetings were held today related to ongoing operations of the spacecraft. The first was an Operational Readiness Review for the propulsion system fuel-side repressurization activity scheduled for January 2009. The second was an AACS flight software (FSW) version A8.7.7 Change Control Board. The updated FSW will be placed onboard the spacecraft in June of 2009 and modifies the default values for the secondary safing vector pair, thruster force magnitudes, and spacecraft mass properties.
Part 2 of the S46 background sequence was uplinked to the spacecraft today. The file will execute on DOY-358, Dec. 23. The Saturn/Rhea DOY 351-354 Live Inertial Vector Propagator Update file was also sent. Both files are registered and activated on-board.
Saturday, Dec. 13 (DOY 348):
Orbit Trim Maneuver (OTM) #177 was performed today. This is the apoapsis maneuver setting up for the Titan 49 encounter on Dec. 21. The main engine burn began at 1:30 PM PST. Telemetry immediately after the maneuver showed the burn duration was 9.725 seconds, giving a delta-V of 1.61 m/s. All subsystems reported nominal performance after the maneuver.
Today the Cassini Plasma Spectrometer (CAPS) led the pointing for the Magnetospheric and Plasma Science (MAPS) instruments' survey of the magnetosphere. ISS observed the F ring for long-term temporal monitoring. The Ultraviolet Imaging Spectrograph (UVIS) mapped volatiles in the immediate neighborhood of Enceladus to test the connection of volatile changes to plume eruptions. The Saturn segment began with CIRS performing a compositional study of Saturn to measure oxygen compounds H2O and CO2 in the stratosphere as a function of latitude.
Monday, Dec. 15 (DOY 350):
At the American Geophysical Union meeting in San Francisco today, there were press briefings held on new Cassini results from Titan and Enceladus. The press releases may be seen at
Port three files were delivered today as part of the Science Operations Plan process for S49. This is the final port for this process. All files and products will be handed off to Uplink Operations on Jan. 9, 2009, for final sequence development.
Most of today's science observations were devoted to regional mapping of the Saturn atmospheric composition by CIRS. The region studied is typically about 15 degrees on a side and in this instance is centered on 45 degrees north latitude.
Tuesday, Dec. 16 (DOY 351):
Nine months ago, to support the Cassini Equinox Mission, the Outreach team began working on a redesign of the Saturn homepage. That new look and feel was released today at
Science today was divided between stellar occultations and polar dynamics studies. The day began with VIMS observing a ring occultation of the star Gamma Crucis - one of the stars in the Southern Cross. The other occultations were of the stars Alp Cru and Beta Centauri by Saturn observed in the ultraviolet by UVIS. These occultations provide temperature of the high atmosphere and vertical profiles of H, H2 and hydrocarbons.
From the dynamics studies, VIMS acquired 3-D imagery of the polar regions in order to study the structure and dynamics of the polar vortices and their variability over time, including seasonal changes. 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.
Visit the JPL Cassini home page for more information about the Cassini Project:
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