Cassini Significant Events 06/29/16 – 07/05/16

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 29, using the 70-meter diameter Deep Space Network station in Spain. 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 flew through periapsis on the dark, south side of Saturn on Wednesday, and then spent the rest of the week climbing out towards a July-11 apoapsis in its inclined orbit. All of the spacecraft's activities were controlled by the on-board command sequence S95, while the flight team worked on developing additional ten-week sequences.

Wednesday, June 29 (DOY 181)

Cassini's Imaging Science Subsystem (ISS) targeted Saturn's A ring for two hours today, looking to re-acquire and study the curious, previously detected "propeller" objects (http://go.nasa.gov/17oqTWF), as well as search for new ones. The Ultraviolet Imaging Spectrograph (UVIS) rode along, observing as well.

After the ISS-led observing was done, UVIS took the reins for 9.3 hours to point the telescopes towards Saturn's southern polar region and study the aurorae there. This observation augments simultaneous observations of that region by the Hubble Space Telescope (HST) from the vicinity of Earth. ISS, VIMS, and the Composite Infrared Spectrometer (CIRS) also observed; opportunities for the ISS imaging were a key component of this campaign with HST.

During the UVIS-led activity, Cassini coasted through periapsis in its orbit #237 of Saturn. It came within 587,000 kilometers from the visible edge of the gas giant, going 35,396 km per hour relative to the planet.

The day's science events closed out with an 89-minute ISS survey of propellers in the rings, with participation from UVIS.

Back on the home planet today, a three-day Titan aeronomy and climate workshop wrapped up at Université de Reims in France.

Thursday, June 30 (DOY 182)

Cassini powered on two additional radio transmitters today for a passage behind Saturn, as seen from Earth. During this Radio Science Occultation experiment, the usual X-band transmission (8 GHz) remained on, but without the usual telemetry symbols and ranging tones "messing up" its pure sine waves. Pure S-band (2 GHz) and Ka-band (32 GHz) transmissions were phase-locked in harmony with the X-band (which, by the way, was locked to a reference signal from Earth). For eight hours, these three continuous radio beams streamed from Cassini, passing through Saturn's rings and parts of its atmosphere. The Radio Science team used Deep Space Network (DSN) stations on three continents to capture and record the resulting signals, which bore the imprints of rings and atmosphere for further scientific study.

After the Radio Science experiment was complete, CIRS pointed its thermal detectors at the dark side of Saturn's A ring for six hours. The moderate-wavelength-resolution spectra it obtained will help place constraints on measurements of that ring's composition and structure. Cassini's extraordinary viewing geometry is illustrated here.

Friday, July 1 (DOY 183)

Today marks 12 years since Cassini fired its main rocket engine for nearly 100 minutes to accomplish Saturn Orbit Insertion (SOI), completing nearly seven years of interplanetary cruise.

Taking full advantage of the back-lit, high-phase-angle viewing geometry, all the Optical Remote-Sensing (ORS) instruments -- ISS, CIRS, VIMS and UVIS -- began 31.5 hours of observing Saturn's various rings.

Saturday, July 2 (DOY 184)

The Raw Images section on the Cassini website has been redesigned to make it easier to step through the latest views from the Saturn system: https://saturn.jpl.nasa.gov/multimedia/raw .

Sunday, July 3 (DOY 185)

Cassini's Navigation team used the ISS for 90 minutes to make images of Saturn's large icy moon Dione against the background stars, for optical navigation purposes.

As soon as the "opnav" imaging was done, UVIS began a campaign to make a total of 217 hours of mosaic scans of Saturn, its magnetosphere, and its rings. The first scan, which started today, would be 42 hours in duration, with ISS and VIMS riding along.

Monday, July 4 (DOY 186)

All eyes were on "that other" gas giant in our solar system tonight. People on the Cassini flight team joined millions worldwide in offering congratulations to the Juno Mission, whose daring Jupiter Orbit Insertion (JOI) event went smoothly. The 35-minute JOI main-rocket-engine burn ended a five-year interplanetary cruise. The elongated shape of Juno's orbits over the course of its mission at Jupiter, with periapses very close to the planet, foreshadow the shape of Cassini's Proximal orbits at Saturn next year, which are illustrated here: /resources/17365 .

Tuesday, July 5 (DOY 187)

The Encke Gap is a 325-km wide lane in the outer part of Saturn's A ring where the little moon Pan races around Saturn. Pan takes only about 13.9 hours to circle the gas giant planet, going more than 60,000 km per hour. Today's featured image shows Pan in the gap it has cleared: /resources/17383 .

On four occasions during the week, while Cassini's optical instruments were pointing at or near Saturn, ISS carried out two-minute Saturn storm-watch observations. VIMS rode along with one of them.

The Deep Space Network communicated with and tracked Cassini on five days this week, using stations in Australia. A total of 10 individual commands were uplinked, and about 909 megabytes of telemetry data were downlinked and captured at rates as high as 124,426 bits per second.

Cassini's path up to mid-day July 5 is illustrated here: http://go.nasa.gov/1tiuUa6 .

Milestones spanning the whole orbital tour are listed here: https://saturn.jpl.nasa.gov/mission/saturn-tour/tour-dates/ .