Cassini Significant Events 8/05/15 – 8/11/15

Cassini is currently orbiting Saturn with a period of 21.8 days in a plane inclined 0.5 degrees from the planet's equatorial plane. The most recent spacecraft tracking and telemetry data were obtained on Aug. 11 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 .

Timed commands from the on-board, 10-week-long S90 sequence continued to control most of Cassini's activities this week. Sequence Implementation Process teams continued work on creating the 10-week command sequences S91, S92 and S93.

While the engineering teams continued to implement the near term command sequences, strategy sessions also continued with a particular emphasis on how to optimize Cassini’s final five periapsis passages.

Wednesday, Aug. 5 (DOY 217)

Science activities for the week began with the Cosmic Dust Analyzer (CDA) performing a 13-hour Saturn stream observation, looking for stream particle periodicities that are related to Saturn’s rotation period.

Thursday, Aug. 6 (DOY 218)

The Imaging Science Subsystem (ISS) performed an observation of the irregular moon, Hyrrokkin. Hyrrokkin, a member of the Norse group of Saturn’s satellites, is about 8 kilometers in diameter, and orbits Saturn with a period of 914 days in an inclined and eccentric retrograde orbit.

Friday, Aug. 7 (DOY 219)

The first of a set of mosaic scans taken of Saturn’s magnetosphere by the Ultraviolet Imaging Spectrograph (UVIS) began today. The scans are part of an 80-hour series focused on the vicinity of the Saturn disk to map the distribution of oxygen.

Cassini coasted through apoapsis today, marking the start of Saturn orbit #220. The spacecraft had slowed to 5,830 kilometers per hour relative to the planet at an altitude of 2.73 million kilometers.

Sunday, Aug. 9 (DOY 221)

The series of UVIS mosaic scans of Saturn’s magnetosphere continued, with a break for Orbit Trim Maneuver (OTM) 417.

OTM-417 successfully executed on the spacecraft. This was the targeting maneuver setting up for the Dione D-5 encounter on Aug. 17, the final close flyby of Dione in the mission. The 18 mm/sec maneuver occurred near apoapsis and shifted the Dione target by about 30 km.

For more on Cassini’s final close flyby of Dione, see
http://saturn.jpl.nasa.gov/news/newsreleases/newsrelease20150813/ .

Monday, Aug. 10 (DOY 222)

A project-wide Mission Planning Forum met today to discuss the reference trajectory update for the Proximal Orbits. There were no changes to the previous version of the reference trajectory until after Titan-126, the final close Titan flyby of the Cassini mission. The talk focused on changes in the Proximal Orbits due to incorporating the latest Saturn atmosphere model and trajectory changes caused by science activities.

An unusual image of Saturn at its rings in the near-infrared, was featured today:
/resources/16221 .

The series of UVIS mosaic scans of Saturn’s magnetosphere continued today. The activity will complete on Wednesday.

Tuesday, Aug. 11 (DOY 223)

During the past week, the DSN communicated with and tracked Cassini on eight routine occasions. A total of 15 command files were successfully uplinked.

This illustration shows Cassini's position on Aug.11: https://space.jpl.nasa.gov/cgi-bin/wspace?tbody=-82&vbody=1001&month=8&day=11&year=2015&hour=23&minute=55&fovmul=1&rfov=45&bfov=30&brite=1&showac=1 .

Milestones spanning the whole orbital tour are listed here: http://saturn.jpl.nasa.gov/mission/saturntourdates .

Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at:
http://saturn.jpl.nasa.gov/mission/presentposition/ .