NASA Cassini Significant Events 07/20/11 - 07/26/11

Status Report From: Jet Propulsion Laboratory
Posted: Tuesday, August 2, 2011

image The most recent spacecraft telemetry was acquired on July 25 from the Deep Space Network tracking complex at Goldstone, California. 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: .

Wednesday, July 20 (DOY 201)

An Autorad Project Interface Test with the DSN was successfully performed yesterday over the Goldstone DSS15 pass. One more demonstration will be performed using larger Spacecraft Message Files (SCMFs), followed by Cassini's operational use of Autorad, which will be for the auto-radiation of some of the commands files being sent to the spacecraft.

A Delivery Coordination Meeting was held today for the initial delivery of the Events software. Events Version 1.1 locates in the spacecraft trajectory instances of specific geometrical and physical events of interest to science opportunity analysts. These may involve the spacecraft as well as planetary objects such as planet, satellites, rings, and magnetosphere. Its principal uses in Cassini operations are for generation of the Tour Atlas when a new trajectory is released and for analysis of timing changes for movable block epochs tied to geometric events. The product of EVENTS execution is an output file which contains times and durations of the specified events in chronological order, as well as an events summary.

Thursday, June 21 (DOY 202)

Starting this week's observations, the Imaging Science Subsystem (ISS) performed astrometric observations of the small moons Calypso, Polydeuces, Helene, Pandora and Epimetheus. Next, around apoapsis, the Ultraviolet Imaging Spectrograph (UVIS) completed a 32 hour system scan of Saturn's magnetosphere to image hydrogen and oxygen in the Saturn system. The Cosmic Dust Analyzer (CDA) completed a 26.5 hour interstellar dust observation, and the Visual and Infrared Mapping Spectrometer (VIMS) and ISS performed two 11-hour exoplanet transit observations. ISS, the Composite Infrared Spectrometer (CIRS), and VIMS performed another observation in the Titan monitoring campaign. Ending the week, ISS performed one more set of astrometric observations of small moons, this time imaging Atlas and Janus among others, and CIRS began a 23 hour mapping activity to determine the upper troposphere and tropopause temperature of Saturn.

Friday, July 22 (DOY 203)

The Navigation team delivered a special trajectory prediction product today in support of a Radio Science Subsystem (RSS) Saturn occultation observation planned for Aug. 1.

In the last week, 130 ISS images and 1,406 VIMS cubes were generated and distributed. Since Jan. 2004, when Saturn Approach Science began, 247,649 ISS images and 121,693 VIMS cubes have been received. VIMS returned a MODE_SYNC_ERROR just after trigger 48 executed, which may account for one missing cube. The trigger was executed on ground support equipment but the error could not be reproduced.

Saturday, July 23 (DOY 204)

The Spacecraft Operations team (SCO) lowered the best lock frequency today by 1.2 kHz. This was to match a gradual drift down in the Telecom Deep Space Transponder Static Phase Error (SPE).

Sunday, July 24 (DOY 205)

The Cassini iPhone App is now available. The Cassini app was designed to give an overview of the spacecraft's current activities, starting with the latest images. Also included in the app is the 'Present Position' of the spacecraft, as well as a countdown to the next major event usually a targeted flyby of one of Saturn's moons. For more information on this subject, link to: .

Monday, July 25 (DOY 206)

The Attitude and Articulation Control Subsystem (AACS) custom telemetry schedule was updated today to include the provision of delta-V estimates every 512 seconds from any thruster firings that may have occurred, such as in support of RWA wheel speed biases.

The second version of AceLog, the replacement tool for the legacy operations log (Olog), was successfully installed in operations today. In addition to smart features that help the project Ace, Acelog V2.0 adds more user interface enhancements and performance improvements, and is capable of monitoring real time data.

A software patch to the Cassini Information Management System (CIMS) Version 3.6.2 was installed today to correct a bug introduced in the deployment of the Oracle 11g upgrade last week.

Tuesday, July 26 (DOY 207)

The most recent Cassini-Huygens Analysis and Results of the Mission (CHARM) teleconference was held today. The topic: "Cassini Huygens Mission to Saturn Seventh Anniversary Part 1 Mission Overview, Highlights of Magnetospheric Science, Titan, Icy Satellites, and Saturn." A PDF of the presentation package may be obtained at: . An audio recording of the presentation was made and will be linked to the same location within a few days.

Scientists met at Caltech for a workshop on Titan surface studies yesterday and today, as well as for a workshop on dunes today and tomorrow.

Port 2 products were due today as part of the S71 Sequence Implementation Process (SIP). The products will be merged and sent out to the flight team for review.

// end //

More status reports and news releases or top stories.

Please follow SpaceRef on Twitter and Like us on Facebook.