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Cassini Significant Events 11/20/2013 - 11/26/2013 Cassini is orbiting Saturn with a 47.9-day period in a plane inclined 49.7 degrees from the planet's equatorial plane. The most recent spacecraft tracking, telemetry, and radio science data were obtained on Dec. 1 using the 70-meter diameter
Deep Space Network station in Australia. Except for the science instrument issues described in previous reports (for more information search the Cassini website for CAPS and USO), the spacecraft continues to be in an excellent state of health with all of its
subsystems operating normally. Information on the present position of the Cassini spacecraft may be found on "Eyes on the Solar System" at
http://1.usa.gov/1as4QYC. The on-board S81 sequence controlled all of Cassini's activities this week. Meanwhile, Cassini's Sequence Implementation Process teams continued working on the ten-week command sequences S82 and S83, with tasks and meetings assigned for
S84 development. Planning also proceeded for the 2016 start of the F-ring and Proximal Orbits phase. Wednesday, Nov. 20 (DOY 324) The Imaging Science Subsystem (ISS), the Composite Infrared Spectrometer (CIRS), and the Ultraviolet Imaging Spectrograph (UVIS) completed a 44-hour long movie of Saturn’s rings. Next, the spacecraft turned to point its high-gain antenna
to Earth; an hour and a half later one of the 34-meter diameter Deep Space Network (DSN) stations in California had begun pointing to Saturn, starting a nine-hour tracking and communications session (one of six this week). During this DSN pass, the Radio Science
team conducted the last of the Superior Conjunction Experiments for the year, capturing Radio Science data at X-band (8 GHz) and Ka-band (32 GHz) to investigate the solar corona. Thursday, Nov. 21 (DOY 325) Occasionally the Attitude and Articulation Control Subsystem (AACS) is commanded to switch to thrusters to stabilize the spacecraft for about an hour while the Reaction Wheel Assemblies (RWAs) are set to optimal speeds. Today's activity
took place while the DSN was not tracking Cassini, so the navigation team will use subsequent telemetry measurements to estimate the thrusters' effect on trajectory. Friday, Nov. 22 (DOY 326) ISS, CIRS and the Visible and Infrared Mapping Spectrometer (VIMS) performed an observation in the Titan monitoring campaign from a distance of 2.7 million kilometers. CIRS then made a 12-hour observation of Saturn to investigate its atmospheric
composition. Saturday, Nov. 23 (DOY 327) ISS, CIRS and VIMS carried out another Titan monitoring investigation, this one from 2.3 million kilometers. ISS then made an observation in the satellite orbit campaign, looking near Saturn for small orbiting objects. VIMS looked at Saturn
for two minutes of storm-watch activity, then watched the red star L2 Puppis for ten and a half hours as it was slowly occulted by the rings due to Cassini's orbital motion. Finally, the Cosmic Dust Analyzer (CDA) began a 23-hour study of dust that orbits
Saturn in the retrograde direction. Sunday, Nov. 24 (DOY 328) Spacecraft engineers performed a routine maintenance activity today involving AACS. It included a test of RWA health, and exercised the Main Engine Assembly gimbal actuators. Monday, Nov. 25 (DOY 329) ISS created a thirteen-hour movie of the Encke Gap in the outer part of Saturn's A ring. This observation was long enough to cover about one orbital revolution of particles in that part of the rings. Of all the data Cassini captures, some of the most remarkable images involve different perspectives on Saturn's extraordinary ring system. Featured today is an image of the rings' dark side, taken at low phase-angle illumination, so the
dense B Ring seems to disappear. It also captures two moons, Daphnis within the A Ring, and Epimethius in the lower foreground.
http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4922 Tuesday, Nov. 26 (DOY 330) UVIS and VIMS inspected Saturn's north polar region for thirteen hours to investigate the aurora. Meanwhile on Earth, flight team members used the latest navigation solutions to design and build commands to turn the spacecraft and fire
its small rocket thrusters. The commands were transmitted to the spacecraft, and they will execute on Nov. 27 to fine-tune Cassini's trajectory for the T-96 Titan flyby coming up on Dec. 1. The flyby page for the T-96 Titan encounter has been set up:
http://saturn.jpl.nasa.gov/mission/flybys/titan20131201. Another page that is available now describes a live educational event coming on Dec. 5 in which Cassini scientists will address students' questions in real time:
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