Cassini Significant Events 09/14/11 – 09/20/11

The most recent spacecraft telemetry was acquired on September 20 from the Deep Space Network tracking complex at Canberra, Australia. The Cassini spacecraft is in an excellent state of health and with the exception of one science instrument being powered off, all subsystems are operating normally. 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/.

Wednesday, Sept. 14 (DOY 257)

The main engine cover was closed on Saturday, Sept. 10, for dust hazard avoidance, and was opened today. This was the 65th in-flight cycle of the cover.

Non-targeted flybys of Methone, Pallene, and Telesto occurred today.

Thursday, Sept. 15 (DOY 258)

Orbit Trim Maneuver (OTM) #290, the T78 cleanup maneuver scheduled for execution today, was found to be unnecessary and was canceled.

Port 2 products were due today as part of the S72 Sequence Implementation Process (SIP). The products will be merged and sent out to the flight team for review.

A non-targeted flyby of Hyperion occurred today.

Friday, Sept 16 (DOY 259)

A feature story called “Cassini Presents Saturn Moon Quintet” is available on the Cassini web site. It describes how with the artistry of a magazine cover shoot, the Cassini spacecraft captured a portrait of five of Saturn’s moons poised along the planet’s rings in a single image. The image was taken in visible green light with the Cassini spacecraft narrow-angle Camera on July 29, 2011. The view was acquired at a distance of approximately 1,100,000 km from Rhea and 1,800,000 km from Enceladus. For more information on this subject and to see the image, link to: https://solarsystem.nasa.gov/news/12564/cassini-presents-saturn-moon-quintet/.

Saturday, Sept. 17 (DOY 260)

Science activities this week kicked off with Cassini's best-ever opportunity to observe the tiny moon Pallene (at ~26,000 km altitude) by the remote sensing instruments (ISS, UVIS, CIRS and VIMS), followed by two observations of Tethys to study the leading hemisphere of this moon and understand interactions with the energetic electrons in the system. Three observations in the Titan monitoring campaign were performed. Imaging Science (ISS), the Composite Infrared Spectrometer (CIRS) and the Visual and Infrared Mapping Spectrometer (VIMS) performed observations of Saturn's faint outer rings (the E ring and the G ring arc) while close to the ring plane. A relatively close flyby of Hyperion (observations made as close as ~90,000 km altitude) followed; observations were made as part of the Scientist for a Day (SFAD) Program. SFAD observations were also made of the transit of the icy moon Tethys across the giant moon Titan. ISS later performed astrometric observations of some of Saturn's small inner moons, and the Magnetometer (MAG) performed an 8 hour calibration with the spacecraft rolling about its X-axis. ISS observed the transits of Enceladus and then Dione across Titan for satellite orbit determination purposes, and then two interstellar dust observations were performed by the Cosmic Dust Analyzer (CDA). The Ultraviolet Imaging Spectrograph (UVIS) performed a 16 hour scan of Saturn’s magnetosphere to study the distribution of the neutral species oxygen and hydrogen.

Monday, Sept. 19 (DOY 262)

Orbit Trim Maneuver (OTM) #291 was performed today. This was the apoapsis maneuver setting up for the Enceladus 14 encounter on Oct. 1. The main engine burn began at 9:45 PM PDT. Telemetry immediately after the maneuver showed a burn duration of 29.42 seconds, giving a delta-V of 5.054 m/s. All subsystems reported normal performance after the maneuver.

Tuesday, Sept. 20 (DOY 263)

Members of the Science Planning and Sequencing Team (SPST) presented early results on some initial modeling of CIRS and VIMS heating violations during the proximal orbits in preparation for a presentation at the upcoming Cassini Project Science Group Meeting (PSG) #55, scheduled for the week of Oct. 24-28, 2011.

Non-targeted flybys of Rhea, Tethys, Pandora, Enceladus, and Janus occurred today.