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Cassini Significant Events 06/01/16 – 06/07/16

Cassini is orbiting Saturn with a period of 23.9 days in a plane inclined 43 degrees from the planet's equatorial plane. The most recent spacecraft tracking and telemetry data were obtained on June 8, using the 70-meter diameter Deep Space Network station in Australia. The spacecraft continues to be in an excellent state of health with all of its subsystems operating normally except for the instrument issues described at http://saturn.jpl.nasa.gov/anomalies .

Cassini whipped around Saturn this Sunday, going 37,547 kilometers per hour relative to the planet at the closest point, and then shot by the huge moon Titan for the planned T-120 encounter on Tuesday. The spacecraft returned telemetry from a long train of science observations of Titan's surface, its atmosphere, and its magnetic and plasma environment. It also took a sizable gravity-assist boost, increasing the spacecraft's orbital inclination from 36 up to 43 degrees with respect to Saturn's equatorial plane; it also shortened Cassini's orbit period to 23.9 days, down from 31.9.

An image from January, featured this week, shows that same haze-enshrouded moon. Cassini's orbit was much closer to equatorial inclination then, as can be seen with Saturn's rings in the foreground. Of note as well are the planet's shadow, and the narrow F ring to the left of center: /resources/17378 .

Wednesday, June 1 (DOY 153)

Cassini's Imaging Science Subsystem (ISS) took a fresh 90-minute look at Titan in the campaign to study its weather. The Visible and Infrared Mapping Spectrometer (VIMS) participated; Titan was at a distance of 2.3 million km from the spacecraft. This observation was carried out two more times on Saturday, at slightly closer range.
Next, ISS made a 50-minute observation in the Satellite Orbit Campaign, looking near the planet for small objects. VIMS and the Composite Infrared Spectrometer (CIRS) rode along.

Following this, the Ultraviolet Imaging Spectrograph (UVIS) had the spacecraft turn to track the bright blue star Delta Scorpii for nine hours, while it appeared to go behind Saturn's rings as a result of Cassini's orbital motion. CIRS rode along. The viewing geometry for this stellar ring-occultation observation is illustrated here, with the star visible to the left of the rings.

After the occultation, UVIS led a 15.3-hour examination of Saturn's 1,528-km diameter icy moon Rhea while it was sunlit at low-phase angles, with VIMS participating. This observation will help determine the composition of Rhea's surface.

Thursday, June 2 (DOY 154)

CIRS stared at the sunlit side of Saturn's dense B ring for six hours, obtaining spectral data at thermal infrared wavelengths for use in studying ring-particle composition.

Saturn is at opposition now, about as close it ever gets to our planet, and rising at sunset. With its rings wide-open toward us, Saturn offers stunning views all night in any telescope. See "What's Up?" for more details about viewing Saturn (as well as "those other" planets visible in the night sky): /news/12910 .

Friday, June 3 (DOY 155)

UVIS, CIRS, ISS and VIMS observed Saturn's 1,123-km wide icy moon Dione for 6.4 hours, in low-phase (nearly full) illumination. After this was completed, CIRS conducted a moderate-resolution compositional stare at Rhea lasting seven hours, with ISS riding along to provide support imaging.

Saturday, June 4 (DOY 156)

Cassini passed through Saturn's ring plane today, and the Cosmic Dust Analyzer (CDA) took full advantage, measuring the minute ring particles that impacted the instrument. The observation lasted 5.7 hours. The Radio and Plasma Wave Science (RPWS) instrument also observed the ring-plane crossing; each time a tiny icy ring particle impacts the spacecraft, it produces a cloud of ions, which RPWS can "hear." UVIS finished out the day performing slow slews across Saturn’s auroral zone for 12.1 hours, to observe the "footprint" of Enceladus's electrical flux tube where it meets Saturn's auroral zone. CIRS and VIMS rode along for this activity.

Sunday, June 5 (DOY 157)

The Magnetometer (MAG) conducted its own Enceladus auroral footprint observation at the start of the day. During the observation, Cassini passed through periapsis, having come within 545,320 km of Saturn's visible limb. The day finished with UVIS and all of the other optical remote-sensing instruments observing the planet’s aurora for nine hours.

Monday, June 6 (DOY 158)

The Radio Science team carried out an occultation experiment today in which Cassini passed behind Saturn's rings as seen from Earth. The spacecraft's continuous radio signals at three frequencies actively probed the rings on their way to Earth, where they were recorded at four Deep Space Network (DSN) stations, spanning three continents. Subsequent study of the results will provide information about the structure of Saturn's rings.

At a Project Science teleconference today, topics included F-ring and proximal-orbit planning, as well as the upcoming 69th Project Science Group (PSG) meeting, which will be held at the European Space Research and Technology Centre (ESTEC) in Noordwijk, Netherlands during the week of June 20.

Tuesday, June 7 (DOY 159)

Today Cassini encountered Saturn's amazing moon Titan. All the details are presented on the T-120 Flyby page: http://saturn.jpl.nasa.gov/news/2909 .

On three occasions this week, while Cassini's optical instruments were pointing at or near Saturn, ISS carried out two-minute storm-watch observations.

The Deep Space Network communicated with and tracked Cassini on six days this week, using stations in Spain, California, and Australia. A total of 10 individual commands were uplinked, and about 1,165 megabytes of telemetry data were downlinked and captured at rates as high as 142,201 bits per second.

This illustration shows Cassini's path up to mid-day June 7, 2016.