Cassini Significant Events 1/6/16 – 1/12/16

Cassini is currently orbiting Saturn with a period of 12.8 days in a plane inclined 1.3 degrees from the planet's equatorial plane. The most recent spacecraft tracking and telemetry data were obtained on January 13 using one of the 34-meter diameter Deep Space Network stations 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/news/significantevents/anomalies .

Cassini made good use of its final days orbiting very near Saturn's equatorial plane but the time has come to begin climbing back up to the final inclined orbits of the Grand Finale. At the next encounter with Titan, which will be T-115 on January 16, the inclination of Cassini's Saturn orbit will begin increasing, eventually setting up for the end of mission in September 2017. A page has been published describing the Titan T-115 encounter: http://saturn.jpl.nasa.gov/mission/flybys/titan20160116 .

Wednesday, Jan. 6 (DOY 006)

As the spacecraft was coasting out towards apoapsis, its Cosmic Dust Detector (CDA) took advantage of the distance from Saturn, and began an observation of interstellar dust that would last about 44 hours.

Back on the home planet 1,600 million kilometers away, the Ultraviolet Imaging Spectrograph (UVIS) science team began its regular semiannual meeting, on the Caltech campus. The bulk of the three days' work focused on results from various science investigations. Saturn's icy satellites, its rings, and Titan featured prominently.

Thursday, Jan. 7 (DOY 007)

Cassini passed its orbital high point, marking the start of Saturn Orbit #230. The apoapsis altitude was 1.96 million km from Saturn, and the spacecraft had slowed to a speed of 6,061 km per hour relative to the planet.

Friday, Jan. 8 (DOY 008)

Cassini's recent close-up of Saturn's little moon Prometheus, which periodically collides with the F ring, made NASA's Astronomy Picture of the Day today. The thin F ring can be seen in the background: http://apod.nasa.gov/apod/ap160108.html .

Saturday, Jan. 9 (DOY 009)

The Imaging Science Subsystem (ISS) began a 13.5-hour observation of Saturn's irregular moon Narvi. This very dark-surfaced object, named after a giant in Norse mythology, is estimated to be about six km in diameter. It occupies a retrograde, inclined orbit that takes it as far as 2.72 million km from Saturn, once every 315 days.

Sunday, Jan. 10 (DOY 010)

After another 13.5-hour Narvi observation, the flight team conducted the first in a series of tests with Cassini's telemetry production and downlink. These tests aim to confirm that every bit of available telemetry data from Cassini's instruments will be "squeezed out" at the end of mission on September 15, 2017, during the critical minutes before plunging to its destruction in Saturn's atmosphere.

Monday, Jan. 11 (DOY 011)

ISS turned to monitor the weather on Saturn's planet-like moon Titan for 90 minutes at a range of 2.8 million km. The Composite Infrared Spectrometer (CIRS) and the Visible and Infrared Mapping Spectrometer (VIMS) also observed. When this was completed, CDA began a 12-hour observation while Cassini, on its way inbound towards its January 14 periapsis, glided across the orbit of Saturn's spongy-looking moon Hyperion.

A spectacular image of Saturn featured today captures the huge ringed planet in northern springtime. Sunlight is coming from the north now, almost upside-down compared to Cassini's views in 2004 when the sunlight was coming from the south: /resources/16293 .

Tuesday, Jan. 12 (DOY 012)

ISS led CIRS and VIMS in another 90-minute Titan monitoring observation, and then CDA took the reins again. Continuing inbound, Cassini was now crossing through the orbit of Titan, and CDA again scanned the equatorial plane for 13 hours, picking up particles from the giant moon's path for in-situ measurement.

During a routine session with the Deep Space Network (DSN) today, Cassini received some freshly prepared commands. In response, the spacecraft turned to the proper attitude and fired its hydrazine-fed rocket thrusters for 34 seconds. This gave the needed change in velocity of 36 millimeters per second, fine-tuning the trajectory for the next Titan flyby, T-115 on January 16. The spacecraft then turned back to resume the DSN session.

On seven occasions during this week, the DSN carried out two-way digital communications with Cassini, while also acquiring radiometric tracking data for navigation, using stations in Australia and California. A total of 162 individual commands were uplinked, and about 1,444 megabytes of telemetry data were downlinked and captured at rates as high as 110,601 bits per second.