Cassini Significant Events 08/24/11 – 08/30/11

The most recent spacecraft telemetry was acquired on August 30 from the Deep Space Network tracking complex at Goldstone, California. 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: http://saturn.jpl.nasa.gov/mission/presentposition/.

Wednesday, Aug. 24 (DOY 236)

The Autorad test scheduled for today was cancelled due to Master Equatorial Controller (MEC) problems at the DSN’s Goldstone DSS-14 station, resulting in the antenna being unable to move to the required azimuthal position. This test will be re-scheduled once the Distributed Object Manager (DOM) changes are complete and DSS-14 is operational.

A non-targeted flyby of Titan occurred today.

Thursday, Aug. 25 (DOY 237)

A flyby of Hyperion occurred today. It was non-targeted, but at a distance of 25,000 kilometers (about 16,000 miles), it was still the second closet encounter with Hyperion in the mission.

Highlights in science data acquisition this week included an observation of Saturn’s aurora by the Ultraviolet Imaging Spectrograph (UVIS) followed by a two hour UVIS calibration activity using the star Spica. A relatively close Hyperion flyby (24,979 km) was used for imaging and spectroscopic observations by Imaging Science (ISS), the Composite Infrared Spectrometer (CIRS), the Visual and Infrared Mapping Spectrometer (VIMS), and UVIS. This was followed by a 15 hour observation of the E and G rings, and a 14.5 hour observation of the faint rings at low elevation angles and low phase performed by VIMS, CIRS and ISS. The Magnetometer performed an 8 hour calibration while the spacecraft rolled about its X-axis, and the Cosmic Dust Analyzer (CDA) completed a 22 hour interstellar dust observation. ISS, CIRS and VIMS performed an observation in support of the Titan monitoring campaign, and ISS performed astrometric observations of a selection of Saturn's small inner moons.

Friday, Aug. 26 (DOY 238)

A feature story called “Cassini Closes in on Saturn’s Tumbling Moon Hyperion” is available on the Cassini web site. It describes how the spacecraft captured new views of Saturn’s oddly shaped moon Hyperion during its encounter with this cratered body on Thursday, Aug. 25. Detailed images were acquired as the spacecraft flew past the moon at a distance of about 25,000 kilometers, making this the second closest encounter with Hyperion in the mission. For images and more information on this subject, link to: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20110826/

Saturday, Aug. 27 (DOY 239)

The videos that accompany the Cassini Scientist for a Day essay contest are now live and available on the Cassini website. The three essay topics this year are Hyperion, Rhea and Titan, and Saturn.

The contest is open to students in grades 5-12 and the deadline for submissions is Oct. 26, 2011. For more information on this subject, go to: http://saturn.jpl.nasa.gov/education/scientistforaday10thedition/targets/.

Monday, Aug. 29 (DOY 241)

The first set of five instrument expanded block (IEB) files was radiated to the spacecraft today over Madrid’s DSS-65 station in support of the S70 background sequence. The S70 sequence will be uplinked on DOY 247 and goes active on DOY 250.

The Downlink Ground System (DGS) team successfully completed the DOM Virtual Internet Protocol (IP) changes today. The Cassini Operational DOM was temporarily unavailable in order to update the DOM with a virtual IP and related configuration changes. And since there are several Cassini tools with dependencies on the OPS DOM, aliveness testing was performed prior to the OPS DOM resuming normal operations.

The Science Forum for S72 was held today. Topics included an overview of science planned for this sequence followed by highlights, unique activities, and highest priority observations as described by the Target Working Team (TWT) and Orbiter Science Team (OST) leads, with comments from the Investigation Scientists and other instrument team representatives.

Tuesday, Aug. 30 (DOY 242)

A mission planning forum was held today to discuss an analysis of trajectory dispersions and uncertainties for the F-ring and proximal orbits performed by the Navigation team. The analysis showed the range of timing and position dispersions which may occur during these orbits. The science and engineering teams will use this information to plan for the F-ring and proximal orbit sequences.

The DGS team completed Data Monitor and Display (DMD) cleanup updates which were installed on all DMD machines in a Cassini test environment, in preparation for user testing. In order to see the DMD page updates on the DMDs, users were instructed to use a "root menu" to bring up the desired DMD. The DMD pages have updated labels, fixed plots, and undefined channels removed, and Broadcast telemetry tools have been replaced with Multicast on the root menus.

The most recent Cassini-Huygens Analysis and Results of the Mission (CHARM) teleconference was held today. The topic: "Cassini Huygens Mission to Saturn Seventh Anniversary -- Part 2 – Highlights of Rings and Dust Science." A PDF of the presentation package may be obtained at: http://saturn.jpl.nasa.gov/video/products/MultimediaProductsCharm/.

An audio recording of the presentation was made and will be linked to the same location within a few days.

Orbit Trim Maneuver (OTM) #288a, an apoapsis maneuver scheduled for Sept. 1, was cancelled today based on the current trajectory estimate being very close to the desired orbit for the upcoming Titan encounter on Sept. 12.

The final set of IEB files was radiated to the spacecraft today over Goldstone’s DSS-14 station in support of the S70 background sequence. Files were verified and confirmed to have been properly uploaded to the Solid State Recorder (SSR).