From: Jet Propulsion Laboratory
Posted: Sunday, October 23, 2011
The most recent spacecraft telemetry was acquired on Oct. 18 from the Deep Space Network tracking complex at Madrid, Spain. 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, Oct. 12 (DOY 285)
A beautiful image of Saturn's rings forming a sundial on the planet's surface was Astronomy Picture of the Day today. It is available at: http://apod.nasa.gov/apod/ap111012.html .
An encounter strategy meeting was held today to cover the period between Oct. 19 and Nov. 6, Enceladus encounters E15 and E16, and maneuvers 296-298 in S70.
The S71 Science Planning and Sequence Team (SPST) leads held a project tag-up meeting today to discuss the potential impact of incomplete DSN resource allocations by the Final Sequence Integration and Validation (FSIV) Sequence Change Request (SCR) need date later this month. The Spacecraft Operations Office (SCO) agreed to plan real-time commands once final allocations are available in late November in order to protect high priority data such as T80 and the Saturn periapsis data.
Today the Attitude and Articulation Control Subsystem (AACS) control mode was changed from Reaction Wheel Assembly (RWA) to Reaction Control Subsystem (RCS) for solar conjunction. The attitude control system went into low rate mode for the first time since a flight software patch was loaded on July 7, 2011, to change the low rate timer from 10 minutes to 40 minutes.
Thursday, Oct. 13 (DOY 286)
Today the spacecraft passed through the mid-point of solar conjunction with a minimum Sun-Earth-Probe (SEP) angle of 2.2 degrees. Ranging data was not used for navigation due to expected biases and the Doppler data was significantly de-weighted. Tracking data should be back to normal by Monday, Oct. 24, when the SEP angle rises above 10 degrees.
Target Working Team and Orbiter Science Team (TWT/OST) integrated products for S73, covering orbits 164 through 168 in April 2012 through June 2012, were delivered today. The integrated products include the first inclined revs of IN-1.
The Instrument Operations System/Multi Mission Image Processing Laboratory (IOS/MIPL) Kerberos server was upgraded to IOS D40 today, with no interruption to operations.
Friday, Oct. 14 (DOY 287)
Cassini Outreach and the JPL Public Service Office supported Pasadena ArtNight with two Art/Science activities at Pasadena's Kidspace Museum. Over 1,000 kids took home their own chalk Saturn moon drawings and Solar System/Constellation art and stories. This is a free evening event held in the fall, consisting of art, music and entertainment as Pasadena's most prominent arts and cultural institutions swing open their doors to the community.
Saturday, Oct. 15 (DOY 288)
The Downlink Ground System (DGS) team successfully completed testing of Acelog V2.0.1 in preparation for an upcoming Delivery Coordination Meeting (DCM) scheduled for Thursday, Oct. 27. The DGS team also took over maintenance responsibility of the Instrument Operations (IO) Gap Summary Tool, a tool that identifies data gaps, by either Earth Received Time (ERT) or Spacecraft Event Time (SCET), that are greater than the specified time delta between adjacent records from an input file.
Sunday, Oct. 16 (DOY 289)
This week in science continued from last week with the spacecraft remaining Earth-pointed during solar conjunction when the Sun-Earth-Spacecraft angle is less than 3 degrees. After Cassini exited solar conjunction, the Ultraviolet Imaging Spectrograph (UVIS), the Composite Infrared Spectrometer (CIRS) and the Visual and Infrared Mapping Spectrometer (VIMS) performed a 12 hour observation of Saturn's aurora, and the Imaging Science Subsystem (ISS), CIRS and VIMS performed two monitoring observations of Titan. Next up is the Enceladus (E15) flyby on Oct. 19.
Monday, Oct. 17 (DOY 290)
The main engine cover was closed today; performance was normal.
Tuesday, Oct. 18 (DOY 291)
A feature story called "Orion's Belt Lights Up Cassini's View of Enceladus" is available on the Cassini web site. It describes how the Cassini spacecraft will take advantage of the position of two of the three stars in Orion's belt when the spacecraft flies by Enceladus on Wed., Oct. 19. As the hot, bright stars pass behind the moon's icy jets, Cassini's ultraviolet imaging spectrograph will acquire a two-dimensional view of these dramatic plumes of water vapor and icy material erupting from the moon's southern polar region. This flyby is the mission's first-ever opportunity to probe the jets with two stars simultaneously, a dual stellar occultation. For images and more information on this subject, link to: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20111018/.
The next maneuver, Orbit Trim Maneuver (OTM) 296, the E15 cleanup maneuver, is scheduled to execute on Oct. 20. OTM-297, targeting the 500 km altitude Enceladus 16 flyby on November 6, is scheduled for Oct. 28.
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