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Cassini Significant Events 11/30/11 – 12/06/11

The most recent spacecraft telemetry was acquired on Dec. 6 from the Deep Space Network tracking complex at Canberra, Australia. The Cassini spacecraft is in an excellent state of health and with the exception of the CAPS instrument being powered off, 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: http://saturn.jpl.nasa.gov/mission/presentposition/.

Wednesday, Nov. 30 (DOY 334)

The Composite Infrared Spectrometer (CIRS) Flight Software (FSW) 6.0.1 patch was installed onboard today. Prior to this patch, the only timing information for CIRS scans was a time stamp for when the first science sample of each scan was obtained from the detectors and stored into the instrument’s internal memory; however, each scan consists of both a forward and backward motion of the scan mechanism. There was no information on the timing of when the scan mechanism completed scanning forward, obtaining science data, and when it was beginning to travel backward in preparation for the next scan. The patch created a new telemetry point and added new data to the science telemetry stream. This new information is provided for each scan and allows the CIRS team to compute the exact time at which the scan mechanism switches directions and begins traveling backward. It also allows for a derived telemetry point to be generated on the ground to let engineers know the true raw sampling rate of the detectors. The detector sampling is hardware controlled and in normal conditions it is constant. When there is interference at certain reaction wheel rates, the CIRS scan mechanism’s velocity varies and sampling is not at a constant rate. This new information provides the calibration team an improved ability to detect anomalous science data that sometimes results from external mechanical interference.

The S74 Engineering Activities Review took place today. At this review, Spacecraft Office personnel take a look at all spacecraft activities to be performed during the S74 sequence.

A software patch delivery for the Cassini Information Management System (CIMS) was delivered today and deployed into operations on Thursday, Dec. 1. Several enhancements were provided as part of this release, which are referenced in approved engineering change request (ECR) 112488.

Port 2 products were due today as part of the S73 Sequence Implementation Process (SIP). The products were merged and sent out to the flight team for review.

Thursday, Dec. 1 (DOY 335)

Orbit Trim Maneuver (OTM) #300a was performed today. This was the apoapsis maneuver setting up for the Dione 3 encounter on Dec. 12 and the Titan 79 encounter on Dec. 13. The Reaction Control Subsystem (RCS) burn began at 4:30 PM PST. Telemetry immediately after the maneuver showed a burn duration of 13.75 seconds, giving a delta-V of 0.021 m/s. All subsystems reported normal performance after the maneuver.

A feature story called “What’s That Sparkle in Cassini’s Eye?” is available on the Cassini web site. It describes how the moon Enceladus, one of the jewels of the Saturn system, sparkles particularly bright in new images obtained by the Cassini spacecraft. The images of the moon, the first ever taken of Enceladus with Cassini's synthetic aperture radar, reveal new details of some of the grooves in the moon's south polar region and unexpected textures in the ice. These images, obtained on Nov. 6, are the highest-resolution images of this region obtained so far. For images and more information on this subject, link to: https://solarsystem.nasa.gov/news/12475/whats-that-sparkle-in-cassinis-eye/.

Friday, Dec. 2 (DOY 336)

The Navigation Team is in the process of determining if the next scheduled maneuver, OTM-301, will be needed; it’s scheduled to execute on Dec. 9. OTM-303, scheduled to execute on Dec. 17, is the cleanup maneuver for the Dione 3/Titan 79 dual flyby.

Saturday, Dec. 3 (DOY 337)

This week’s science highlights included three interstellar dust observations performed by the Cosmic Dust Analyzer (CDA). The Imaging Science Subsystem (ISS) performed astrometric observations of some of Saturn's small moons including Helene, Calypso and Epimetheus, followed by five images taken for optical navigation purposes. CIRS made a 23-hour mid-infrared (mid-IR) observation of Saturn to measure upper troposphere and tropopause temperatures. Finally, the Magnetometer (MAG) performed an 8 hour calibration while the spacecraft rolled about its X-axis.

Today a member of the Cassini Outreach team received a Visionary Award from the Women’s International Film and Television Showcase (WIFTS). The award is in recognition of her invention, the Blissymbol Printer, which was created for a seventh grade science fair project over 25 years ago.

Sunday, Dec. 4 (DOY 338)

The U.S. Cassini Scientist for a Day winners, finalists, and honorable mention winners have been officially notified, and the names will be posted on the Cassini website next week.

In preparation for the upcoming Dione 3 encounter on Monday, Dec. 12, a ‘‘D-3’ flyby page is now available on the Cassini web site along with promotional art. Any noteworthy results from the D-3 flyby as well as additional links and images will be posted at: http://saturn.jpl.nasa.gov/mission/flybys/dione20111212/.

Monday, Dec. 5 (DOY 339)

An encounter strategy meeting was held today to cover the period between Dec. 12 and Jan. 2, Dione and Titan encounters D-3, T-79, and T-80, and maneuvers 303 and 304 in S71.

Preliminary Sequence Integration and Validation (PSIV) Spacecraft Activity Sequence File (SASF) – Merge 1 products were published last week as part of the S72 Sequence Implementation Process (SIP). The PSIV-Merge 2 was published today in support of the S72 split needed due to the sequence size. The split of the S72 sequence is planned to fall on DOY-062.

Tuesday, Dec. 6 (DOY 340)

A mission planning forum was held today to review propellant use in S70 and the status of the propellant budgets. A consumables status is provided on a regular basis so the Project can maintain cognizance of propellant usage and end of mission margins.