Cassini is orbiting Saturn with a 12-day period in a plane inclined 59.4 degrees from the planet's equatorial plane. The most recent spacecraft tracking and telemetry data were obtained early on June 19 using the 70-meter diameter Deep Space Network station at Canberra, Australia. Except for some 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 the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/.
Though not reported here every week, Cassini spends a good amount of time carrying out essential calibrations of its science instruments and experiments to ensure accurate results. There are various engineering activities to take care of as well; several times per week, for example, the Attitude and Articulation Control Subsystem team executes Reaction Wheel Assembly bias maneuvers to adjust Cassini's wheel speeds, while thrusters stabilize the spacecraft.
Wednesday, June 12 (DOY 163)
At the start of the day and then again mid-day, the Imaging Science Subsystem (ISS), the Ultraviolet Imaging Spectrograph (UVIS), and the Visible and Infrared Mapping Spectrometer (VIMS) observed one of the largest of Saturn's 38 known irregular moons, Albiorix. These observations will help determine its rotation period and its pole-axis orientation, and develop a shape model for the object, which has a diameter of approximately 30 to 40 kilometers. In between these observations UVIS and VIMS watched an ingress solar occultation as the Sun went behind Saturn, and then ISS led an observation of the plumes that jet from the small icy moon Enceladus.
The Magnetospheric and Plasma Science instruments took measurements as the spacecraft passed through Saturn's ring plane, and the Radio and Plasma Wave Science Subsystem (RPWS) examined Saturn's aurora and Kilometric (radio-wavelength) Radiation (SKR) in the auroral magnetosphere and SKR source regions.
Thursday, June 13 (DOY 164)
The Composite Infrared Spectrometer (CIRS) led a sit-and-stare observation of Saturn's northern aurora to derive composition while the spacecraft traveled through periapsis going 33,220 kilometers per hour relative to the planet, at about 555,000 kilometers above the clouds. VIMS led a movie centered at Saturn's north pole. VIMS and CIRS then observed the red star R Carinae as it was occulted by Saturn.
Friday, June 14 (DOY 165)
ISS led the optical instruments as they investigated Saturn's north-pole vortex, then led a distant Titan cloud observation. Following this, ISS took another look at Albiorix while UVIS measured the object's albedo in ultraviolet light.
Saturday, June 15 (DOY 166)
CIRS observed the lit side of the rings to obtain spectra in the thermal infrared for ring particle composition studies. All four optical remote-sensing instruments (CIRS, ISS, UVIS, VIMS) then observed Saturn's satellite Tethys at low phase, before ISS made an observation in the Satellite Orbit Campaign to look for small objects near the planet.
Sunday, June 16 (DOY 167)
ISS, CIRS and VIMS carried out a Titan monitoring observation from 2.2 million kilometers away, then ISS reacquired and tracked the orbits of known propellers (http://go.usa.gov/YyGR). CIRS observed Saturn to collect composition data, then ISS imaged the faint rings at low elevation and at low phase angle.
Monday, June 17 (DOY 168)
The Cosmic Dust (CDA) began a 37-hour observation of dust moving in retrograde orbits about Saturn.
A view of the day-night terminator on Saturn's large icy moon Dione is today's featured image: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4828
Tuesday, June 18 (DOY 169)
The "Wave at Saturn" campaign was launched today. On Friday, July 19, Cassini will linger in the shadow of Saturn making valuable observations of the planet and its rings at very high phase angles, in which forward-scattered light best shows off the smallest of ring particles. The main science goal will be to look for change over time in the more diffuse rings. As it was in the now-famous image taken in 2006, the pale blue dot of Earth will again be in the field of view. The Cassini Project is therefore suggesting that we Earthlings commemorate the occasion by going outside and looking toward Saturn at the moment when light reflected from Earth will begin its eighty minute trip to the open shutters on Cassini's cameras: http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20040618/