From: Jet Propulsion Laboratory
Posted: Monday, October 22, 2012
The most recent spacecraft tracking Oct. 17 by the Deep Space Network's 70 meter Station 14 at Goldstone, California. Except for the Cassini Plasma Spectrometer, which is off, and the failed Ultrastable Oscillator, the Cassini spacecraft continues to be in an excellent state of health with all its subsystems operating normally. Information on the present position of the Cassini spacecraft may be found on the "Present Position" page at: http://saturn.jpl.nasa.gov/mission/presentposition/ .
As Saturn approaches the Sun as seen in Earth's sky, communications with Cassini for tracking, navigating, commanding, and telemetry become noisier than usual. Last week, the Radio Science team collected data to characterize the solar corona, illustrating that one team's noise is another team's data. This week, though, the "quiet period" approaching conjunction was used to begin a propellant gauging test on the spacecraft, as described for Friday below.
Wednesday, Oct. 10 (DOY 284)
At infrared wavelengths, CW Leonis is the brightest star in our sky aside from the Sun. The Composite Infrared Spectrometer (CIRS) spent eight hours observing it today to perform an instrument calibration.
The flight team uplinked commands to execute a calibration of the Cosmic Dust Analyzer's articulation positions, and to adjust the spacecraft's downlink telemetry rates for next week to accommodate an updated Deep Space Network (DSN) tracking schedule.
Thursday, Oct. 11 (DOY 285)
The Imaging Science Subsystem (ISS) began a 29.5-hour movie of the lit face of the rings at high phase to search for periodicities in the spokes.
Telemetry indicated a possible problem with the CIRS Bus Interface Unit (BIU), and an anomaly meeting was called.
Scientists have reconstructed the behavior of the Huygens Probe, which Cassini deployed to Titan, as it encountered the soft, damp sand after parachuting to the cold moon's surface. The news feature was released today with an accompanying animation. They may be viewed here: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20121011/
Friday, Oct. 12 (DOY 286)
The CIRS BIU anomaly was confirmed and commands were sent to do a reboot. The instrument was confirmed to be back in its normal state after a round trip light-time of almost three hours.
ISS performed another observation in the Satellite Orbit Campaign and then began a 42-hour movie similar to Thursday's. CIRS and the Visible and Infrared Mapping Spectrometer (VIMS) rode along with this observation.
The Spacecraft Operations Office (SCO) began a Propellant Gauging Test (PGT) that will run on the spacecraft through October 29, controlled by the S75 background sequence. By varying thermal conditions, SCO engineers plan to obtain a better estimate of the amount of propellant remaining in the main tanks. The main engine cover was closed today, with the four bus heaters and the main engine heater on, beginning the heating phase of the PGT. The cooling phase will begin on October 19.
Saturday, Oct. 13 (DOY 287)
ISS, CIRS and VIMS continued observing the rings.
Sunday, Oct. 14 (DOY 288)
The Attitude and Articulation Control Subsystem team executed two Reaction Wheel Assembly bias maneuvers this week to adjust wheel speeds. The one today was conducted while the DSN tracked Cassini, and the one on Tuesday was not tracked.
CIRS began a 13.5-hour observation of Saturn to measure oxygen compounds (H2O, CO2) in the stratosphere.
Monday, Oct. 15 (DOY 289)
Today was the 15th anniversary of Cassini's launch. The feature "A Long and Winding Road: Cassini Celebrates 15 Years" and a new illustrated timeline may be viewed here: http://saturn.jpl.nasa.gov/news/cassinifeatures/20121015/
ISS, CIRS and VIMS created a 7-hour movie of the D-ring at high-phase illumination, a unique opportunity in 2012. ISS then began a 16-hour F-ring movie.
An image of Saturn's largest moon, Titan, featured today shows off some differences between the north and south polar regions. "Titan's Varied Atmosphere" may be seen here: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4644
As scheduled, the Cassini Shining Moments poll was closed today. Results may be found here: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20120926/
Tuesday, Oct. 16 (DOY 290)
VIMS performed a calibration of its solar port.
Commands were approved for the first four of the ten S76 Instrument Expanded Blocks that will be uplinked next week.
Local Cassini flight team members met today to send off a long-time secretary, who may be seen standing front center in the photo here: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4652
The feature titled, "What's Baking on Titan?" was published today, discussing some new curiosities revealed by Cassini's synthetic aperture radar imaging of Titan's surface. It may viewed here: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20121016
Visit the JPL Cassini home page for more information about the Cassini Project: http://saturn.jpl.nasa.gov/
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