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NASA Cassini Significant Events 01/12/11 - 01/18/11

Status Report From: Jet Propulsion Laboratory
Posted: Saturday, January 22, 2011

image The most recent spacecraft telemetry was acquired on Jan. 17 from the Deep Space Network tracking complex at Madrid, Spain. The Cassini spacecraft is in an excellent state of health and 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, Jan. 12 (DOY 012)

This week in science began with two calibrations: the Composite Infrared Spectrometer (CIRS) performed an 8 hour scattered stray light test and the Ultraviolet Imaging Spectrograph (UVIS) executed a 3 hour stellar calibration with the star Spica. The Cassini Plasma Spectrometer (CAPS) then completed a 14.5 hour low latitude Saturn observation at apoapsis. The Composite Infrared Spectrometer (CIRS), Imaging Science (ISS) and VIMS performed distant observations of Titan to monitor the atmosphere and cloud activity and look for surface changes across the anti-Saturn hemisphere of Titan. The Magnetometer performed an 8 hour calibration with the spacecraft rolling about its X-axis. ISS made astrometric observations of Saturn's small, inner moons Polydeuces, Telesto, Methone, Pandora, Atlas, Anthe, and Epimetheus.

Thursday, Jan. 13 (DOY 013)

Commands were uplinked to the spacecraft today in support of the S66 Magnetospheric Imaging Instrument (MIMI) Ion and Neutral Camera(INCA) high voltage Instrument Expanded Block (IEB) update; the MIMI instrument team verified that the commands to load the new IEBs executed properly. The S66 background sequence was also radiated to the spacecraft and will begin execution on DOY 017; the uplink team confirmed successful receipt of the S66 background sequence.

Attitude and Articulation Control Subsystem (AACS) Periodic Engineering Maintenance was completed today. This activity, performed approximately every 90 days, spins up the reaction wheel assembly #3 (RWA-3) to 100 rpm for lubrication purposes, exercises the back-up Engine Gimbal Assembly, and verifies the Back-up Assisted Load Format Injection Loader (BAIL) software.

A feature story called "Cassini Rocks Rhea Rendezvous" is available on the Cassini web site. It describes how the Cassini spacecraft completed its closest flyby of Saturn's moon Rhea, returning high resolution images of the icy moon's surface. Pictures of the Rhea surface taken around the time of closest approach at 4:53 AM UTC on Jan. 11 show shadowy craters at a low sun angle. A portrait of a bright, icy Rhea also captures Saturn's rings and three other moons clearly visible in the background. For more information on this subject link to: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20110113/.

Friday, Jan. 14 (DOY 014)

Orbit Trim Maneuver (OTM) #275 was performed today. This was the clean-up maneuver following the Rhea 3 encounter on Jan. 11. The main engine burn began at 6:45 AM PST. Telemetry immediately after the maneuver showed a burn duration of 15.97 seconds, giving a delta-V of 2.76 m/s. All subsystems reported nominal performance after the maneuver.

Today is the sixth anniversary of the Huygens Probe entry, descent, and relay, which landed on the surface of Titan on Jan. 14, 2005.

Saturday, Jan. 15 (DOY 015)

The command loss timer value was set to 115 hours today. This is the new default value for the Solstice Mission.

Sunday, Jan. 16 (DOY 016)

The Downlink Ground System (DGS) team submitted a Perimeter Access Request (PAR) in support of the Java Distributed Object Manager (DOM) transition and testing task. The PAR system allows service providers to request IP service access by protocol and port to a host, along with workflow for approval, request tracking, and documentation. Java DOM training and demonstrations are scheduled and will be provided next week during the Project Science Group (PSG) meeting #53 beginning Jan. 24.

Monday, Jan. 17 (DOY 017)

The S66 sequence began execution today at 2011-017T08:42:00. The sequence will run for 49 days and conclude on March 7. During that time there will be one targeted encounter of Titan and seven non-targeted flybys - two of Enceladus and one each of Epimetheus, Calypso, Helene, Pallene, and Tethys. Four OTMs are scheduled, numbered 276 through 279.

Tuesday, Jan. 18 (DOY 018)

A Mission Planning forum was held today to review the status of the instrument and spacecraft consumables tracked by MP. The status of the consumables as of the end of Equinox Mission was reported and consumables nearing or exceeding their allocation were identified. Periodic reviews of consumables status allow the project to stay informed of consumable use and identify high use consumables.

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