The Cassini spacecraft is orbiting Saturn with a period of 13.3 days and inclined 53 degrees from the equatorial plane. The most recent spacecraft tracking and telemetry data were collected on Jan. 2 by two arrayed 34 meter Deep Space Network Stations at Madrid, Spain. Except for some science instrument issues described in previous reports, 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 the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.
Between holidays, flight team members continued working on the ten-week command sequences S77 and S78, which will go active on the spacecraft in mid-January, and in March, respectively. In flight, Cassini continued executing commands from S76.
Wednesday, Dec. 26 (DOY 361)
The Composite Infrared Spectrometer (CIRS) completed a 16 hour observation of Saturn's stratosphere, then the Imaging Science Subsystem (ISS) made a close-in observation of the D ring, Saturn's innermost ring, at low phase illumination.
Today's featured image was taken during last week's non-targeted encounter with Saturn's 1,530-kilometer diameter moon Rhea. It may be viewed here: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4709
Thursday, Dec. 27 (DOY 362)
ISS performed another observation in the Satellite Orbit Campaign, then turned to Aegaeon, the kilometer-size object embedded in the G ring, to observe its orbit at low phase. ISS and the Visible and Infrared Mapping Spectrometer (VIMS) performed another observation in the Titan monitoring campaign from two million kilometers away.
Today, and again on Saturday and Sunday, Deep Space Network stations participated in Operations Readiness Tests for the Radio Science atmospheric occultation experiment planned for Jan. 5.
Friday, Dec. 28 (DOY 363)
CIRS performed an eight hour calibration using the star CW Leonis, whose energy is emitted mostly at infrared wavelengths.
Saturday, Dec. 29 (DOY 364)
The Attitude and Articulation Control Subsystem team executed a reaction wheel assembly bias maneuver to adjust wheel speeds, while thrusters stabilized the spacecraft. The Navigation team relied on telemetry played back later, rather than realtime Doppler data, to model the thrusters' effects on the trajectory.
Cassini passed through apoapsis at a height of 1.7 million kilometers, having slowed to 10,901 kilometers per hour relative to the planet.
Sunday, Dec. 30 (DOY 365)
VIMS, CIRS, and the Ultraviolet Imaging Spectrograph (UVIS) performed a 12 hour joint observation of the dark side of the rings, with ISS taking data as a ride-along near the end. ISS then created a 10.5 hour movie of the Encke Gap in the outer A ring.
Monday, Dec. 31 (DOY 366)
A remarkable image featured today shows the eight kilometer-long moon Daphnis and the gravitationally induced wakes it creates in the A ring material on either side of the narrow Keeler gap. It may be seen here: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4708
Cassini's beautiful image of Saturn and the dark side of its rings, taken on Aug. 19, 2012, was featured as today's Astronomy Picture of the Day. It can be viewed here: http://apod.nasa.gov/apod/ap121231.html
Tuesday, Jan. 1 (DOY 001)
CIRS mapped ring temperatures in Saturn's shadow in order to measure the particles' thermal inertia.