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Cassini Significant Events 09/21/11 – 09/27/11

The most recent spacecraft telemetry was acquired on September 27 from the Deep Space Network tracking complex at Madrid, Spain. The Cassini spacecraft is in an excellent state of health and with the exception of one science 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, Sept. 21 (DOY 264)

An encounter strategy meeting was held today to cover the period between Oct. 1 and Oct. 19, Enceladus encounters E-14 and E-15, and maneuvers 294 and 295 in S70.

A feature story called “Saturn’s Moon Enceladus Spreads Its Influence” is available on the Cassini web site. It describes how the small, dynamic moon spews out plumes of water vapor and ice, first detected by the magnetometer on the Cassini spacecraft in 2005. Enceladus has simple organic particles and may house liquid water beneath its surface. Its geyser-like jets create a gigantic halo of ice, dust and gas around Enceladus that helps feed Saturn’s E ring. Thanks to those icy jets, Enceladus is the only moon in our solar system known to substantially influence the chemical composition of its parent planet. For more information on this subject, link to: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20110921/.

A software point delivery for the Cassini Information Management System (CIMS) was delivered and installed today. Several enhancements were provided as part of this CIMS V3.7 release, which are referenced in approved engineering change requests (ECRs) 111988, 111990, 112011, 112010, and 112008.

Thursday, Sept. 22 (DOY 265)

The post Orbit Trim Maneuver 291 orbit solution was completed, and based on its results the Navigation team recommended that OTM-292 be executed. OTM-292 is the Enceladus (E-14) approach maneuver, scheduled to execute Wednesday, Sept. 28. OTM294 and OTM295 follow on Oct. 4 and Oct. 9, respectively. There is no OTM293 maneuver, this number was skipped to maintain the “modulo 3” numbering nomenclature.

The command loss timer reset command sent to the spacecraft today was received with a frame header error. A double error was detected and a single error was corrected; nevertheless, the command loss timer was properly reset.

The Multi-mission Ground Systems and Services Office (MGSS) conducted the Software Delivery and Deployment Review (DDR) for the Instrument Operations System/Multi Mission Image Processing Laboratory (IOS/MIPL) D40 today, where the delivery was approved for Cassini operations.

Friday, Sept. 23 (DOY 266)

Science highlights this week included satellite searches near the Rhea and Dione L5 Lagrange points performed by the Imaging Science (ISS) and the Visual and Infrared Mapping Spectrometer (VIMS). The Ultraviolet Imaging Spectrograph (UVIS) made two system scan measurements, mapping out the neutral oxygen and hydrogen in the inner Saturn system. ISS performed astrometric observations of some of Saturn's small inner moons as well as a Saturn observation as part of the Scientist for a Day (SFAD) program. The Cosmic Dust Analyzer (CDA) performed two interstellar dust observations, and ISS observed Titan for six hours as part of a long range monitoring campaign. The Composite Infrared Spectrometer (CIRS) made measurements of the composition of Titan’s atmosphere for six hours, and ISS and UVIS concluded the week with a 15 hour observation of the outer irregular moon Skoll.

Saturday, Sept. 24 (DOY 267)

Today a downlink processing job stalled while interacting with the IO/MIPL database, apparently due to simultaneous attempts to access a data set in the database. This froze interactions to some of the tables and prevented automated jobs from running. Processes were killed in order to free up the access, and processing was manually recovered on Monday.

Monday, Sept. 26 (DOY 269)

The Cassini Project is preparing to release a new set of Dione Atlas images and PDFs on Wednesday, Sept. 28. They’ll be available at the following link, as well as in the Photojournal, JPL’s image website:

Tuesday, Sept. 27 (DOY 270)

A mission planning forum was held today to discuss dust hazards and propellant budgets status. The dust hazards for the remainder of the mission and changes in the hazards due to the 110818 reference trajectory release were reviewed. Dust hazards occur when the spacecraft flies through a region which may contain dust particles large enough to cause damage to the spacecraft and the risk is sufficient to warrant protective measures. A consumables status is provided on a regular basis so the Project can maintain cognizance of propellant usage and end of mission margins.

The most recent Cassini-Huygens Analysis and Results of the Mission (CHARM) teleconference was held today. The topic: "A Year in the Life of Cassini." 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.