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Cassini Significant Events 09/16/09 – 09/22/09

The most recent spacecraft telemetry was acquired on Sept. 22 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/operations/present-position.cfm

Wednesday, Sept. 16 (DOY 259):

The Cassini Scientist for a Day Fall 2009 Essay Contest is currently underway. To celebrate the International Year of Astronomy, this 8th edition of the contest is open to all nations and educational organizations. Each country and/or educational organization is encouraged to run the contest either following our guidelines or customizing them to fit their needs.

In the US, students in grades 5-12 may enter with a fast approaching entry deadline of September 30, 2009, at noon Pacific Time. All essays will be evaluated by Cassini scientists, flight team members, and educators. Winning essays will be selected for each target. Outside the US, sponsoring organizations are tasked to select a deadline, collect and judge the essays, and to send the winning entries to the Cassini Outreach Team. Winners and their classmates will be invited to participate in a web-based videoconference with Cassini scientists.

The actual observation for this contest is scheduled for October 11. The Science Planning team designed three possible observation opportunities. Target number 1 is Saturn and its rings. Number 2 is Tethys with Saturn's rings, and number 3 is Titan. For more information link to:

Thursday, Sept. 17 (DOY 260):

On the Cassini Website, under News & Features, one can find a link to the Cassini Science League. Launched in August of this year, the League endeavors to share with the public more of the large and diverse volume of science generated by the scientists on the Cassini mission. Each Science League entry will highlight a science paper ­ or set of interrelated papers - and provide information on the publication in which the paper appears.

The first two articles "Resolving Rain over Xanadu" and "Titan and Earth¹s Future Atmosphere: Lost to Space" appeared in September and August respectively. Release #3 is due out before the end of September. To access the articles link to:

Friday, Sept. 18 (DOY 261):

Non-targeted flybys of Prometheus and Dione occurred today.

Sunday, Sept. 20 (DOY 263):

With the spacecraft and Saturn finally far enough removed from superior conjunction ­ a three-degree separation angle ­ science data acquisition and playback activities have resumed. The final portion of the Rings Equinox campaign ran from Sunday, Sept. 20, through Sept. 24. The entire set of ring observations during equinox were deemed as the highest value rings science of the Extended Mission. The observations for the RINGS discipline group in these segments were designed to look for ring phenomena that scientists have never had the opportunity to study before.

Monday, Sept. 21 (DOY 264):

Science Planning hosted a presentation on the science highlights for sequence S58 with a focus on what is unique and what observations have the highest priority. This information will help the flight team as the sequence goes through the development process, and assist in making trades should the need arise. The files for the first input port are due Wednesday.

Scientists are marveling over the extent of ruffles and dust clouds revealed in the rings of Saturn during the planet's equinox crossing last month. Once thought to be almost completely flat ­ at most 10 meters thick - new images of the rings reveal some newly discovered ³bumps² as high as the Rocky Mountains. For the full story, link to:

A slideshow with highlights from Cassini¹s five-year tour of Saturn, "The Saturn System: A Feast for the Eyes," was also released Monday:

Completing an observation that began on the previous day, VIMS monitored Saturn¹s rings following the equinox. Next came an observation in the CIRS campaign to monitor the long-term trends in ring temperatures as the Sun moves north across the ring plane during the equinox and illuminates that side of the rings that hasn¹t seen direct sunlight in over 14 years. ISS then turned to study what have come to be known as "propellers," features that indicate the presence of ring particles large enough to disturb the ring particles in their vicinity but not so large as to be able to open a gap in the rings.

Tuesday, Sept. 22 (DOY 265):

Today Cassini and the equinox images were mentioned on NBC Nightly News. The piece was called "NASA Offers a New View of Saturn." The story can be viewed online at:

After reaching a separation (SEP) angle of 4 degrees, Cassini officially exited superior conjunction. The minimum SEP angle of 1.95 degrees occurred on Sept. 17. One hundred "NO-OP" commands were sent on each pass from September 15 through September 19 to test the conjunction command link.

A non-targeted flyby of Titan occurred today.

The Target Working Team (TWT)/ Orbiter Science Team (OST) integrated products for S59, covering orbits 129 through 131, from April through May, 2010, were delivered today. The integrated products are in their final form and no re-integration is planned. The next step in sequence development, Science Operations Plan (SOP) implementation, will kick off on Oct. 7. Between now and then, the instrument teams will be working on pointing designs for the sequence. TWT/OST teams deliver integrated sequence products for the extended mission about every five weeks.

The DSN schedulers provided a fully negotiated S55 allocation file at this point in the Science Operations Plan Process. Because of this, there was enough time to perform the Sponge Bit process. This process allowed Science Planning to give out extra data volume for selected periods of time where there was SSR and downlink margin. The process began on the 21st with the publication of an update to the Solid State Recorder Management Tool report, and a Sponge Bits package specifying the amount of data volume per period that was available. A representative from each science team then reviewed the package and discussed with their team members if they could take advantage of the available data volume in each period. Based on the inputs received, the science planner next updated the Sponge Bits package with a proposed allocation. Then during the actual Sponge Bits meeting on Tuesday, Sept. 22, the allocation was reviewed and approved. Bottom line - more data for science!