From: Jet Propulsion Laboratory
Posted: Friday, November 11, 2011
The most recent spacecraft telemetry was acquired on November 8 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 the CAPS 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, Nov.2 (DOY 306)
An encounter strategy meeting was held today to cover the period between Nov. 6 and Dec. 13, Enceladus, Dione and Titan encounters E-16, D-3 and T-79, and maneuvers 299-301.
Navigation Team and Science Planning and Sequencing Team members reviewed current trajectories with and without Orbit Trim Maneuver 298 (OTM-298), the final targeting maneuver for E-16 scheduled to execute today, and determined that OTM-298 was not needed. Consequently, OTM-298 was canceled.
Thursday, Nov. 3 (DOY 307)
Science activities this week began with the final 15 hour Titan Exploration at Apoapsis (TEA) observation (in the set of TEAs begun last week) by the Composite Infrared Spectrometer (CIRS) and Imaging Science Subsystem (ISS). This was followed by a set of ISS astrometric observations of some of Saturn's small inner moons, and a CIRS 12 hour observation of Saturn to measure oxygen compounds (H2O, CO2) in the stratosphere. The Ultraviolet Imaging Spectrograph (UVIS), CIRS, and the Visual and Infrared Mapping Spectrometer (VIMS) completed an 11 hour observation of Saturn's aurora, which was followed by the E-16 Enceladus flyby at 496 km altitude. The primary goal of this flyby was to perform the first close Synthetic Aperture Radar (SAR) measurements of an icy satellite to understand the structure and composition of the regolith directly below the surface, and to compare these data with similar measurements of Titan. In addition to the Radar observations, remote sensing measurements were made of Enceladus' plume on the inbound leg to aid in understanding the structure and morphology, temporal variability, and relationship to geological features and hot spots on the surface; on the outbound leg the surface of Enceladus was observed to obtain thermal and compositional data. UVIS made a long (5.25 hr) Dione observation to measure its UV spectral albedo and search for an exosphere, and then performed a calibration measurement of the star Spica. ISS made searches for objects in the L5 Lagrange regions of both Enceladus and Rhea. Lastly, Saturn auroral observations were led by UVIS, with repeated slews across the auroral oval, and ISS then performed a satellite search in the region around the Titan L4 Lagrange point.
Friday, Nov. 4 (DOY 308).
The main engine cover was closed today and will re-open on Sunday, Nov. 6. This was the 68th in-flight cycle of the cover.
Saturday, Nov. 5 (DOY 309)
Real Time Operations (RTO) uplinked the S71 Instrument Expanded Block (IEB) files over the weekend using the new Autorad tool successfully.
Sunday, Nov. 6 (DOY 310)
Today Cassini flew by Enceladus at an altitude of 496 kilometers and a speed of 7.4 km/sec. This flyby was designed to obtain the first detailed radar observations of Enceladus. This was also the first close radar pass of any icy moon besides Titan. The results will enable a comparison of the radar properties of a moon with a known composition (Enceladus) with that of Titan. The segment also included plume observations, the composite infrared spectrometer (CIRS) monitoring of hotspot activity, ultraviolet imaging spectrograph (UVIS) observations of Dione and its environment, and searches for Lagrangian companions of Enceladus and Rhea. For more information and raw images, link to: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20111107/
Non-targeted flybys of Methone, Pandora, and Calypso occurred today.
Monday, Nov. 7 (DOY 311)
The Science Forum for S73 was held today. Topics included an overview of science planned for this sequence followed by highlights, unique activities, and highest priority observations as described by the Target Working Team (TWT) and Orbiter Science Team (OST) leads, with comments from the Investigation Scientists and other instrument team representatives.
Tuesday, Nov. 8 (DOY 312) Orbit Trim Maneuver (OTM) #299 was performed today. This was the clean-up maneuver following the Enceladus 16 encounter on Nov. 6. The main engine burn began at 5:45PM PDT. Telemetry immediately after the maneuver showed a burn duration of 12.029 seconds, giving a delta-V of 2.09 m/s. All subsystems reported nominal performance after the maneuver.
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