Cassini Significant Event Report

For Week Ending 07/25/03

The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Wednesday, July 23. The Cassini spacecraft is in an excellent state of health and is operating normally. Information on the spacecraft's position and speed can be viewed on the "Present Position" web page.

On-board activities this week included Radio and Plasma Wave Science (RPWS) High Frequency Receiver (HFR) calibrations, Cosmic Dust Analyzer decontamination and Instrument Expanded Block (IEB) load execution, Visual and Infrared Mapping Spectrometer (VIMS) functional test and deep space characterization, and Saturn Orbit Insertion (SOI) demo sequence uplink to RAM. Memory read outs have verified that the sequence was successfully loaded into RAM, and is registered but not active in both the prime and online strings.


On July 18, a real-time command moratorium was initiated to support the SOI sequence demonstration. It will be in effect until August 5. Commanding is planned during this time frame. At the end of each commanding period, a new command loss timer (CLT) value will be uplinked. This will simulate the SOI situation where deliberate management of the CLT hedges against a hardware command decoder failure.


Mission Support and Services Office personnel conducted an Emergency Control Center (ECC) demonstration at the DSS complex at Goldstone, California. The demo confirmed the capability to flow telemetry, and to issue commands from the ECC.


The C39 Final Sequence Integration and Validation (FSIV) sequence generator, sequence translator, and sequence of events generation products corresponding to the merged files have been released for review by the Spacecraft Operations Office (SCO) and instrument teams. These products include the Sequence Change Requests (SCR) approved at the July 11 SCR approval meeting, as well as some instrument internal changes which did not require change documentation.


S07/S08 Science Operations Plan implementation process completed this week, with a final wrap-up meeting scheduled for next week.


A waiver disposition meeting was held this week as part of the S14 Science and Sequence Update Process (SSUP) Verification and Validation (V&V) activity. In addition, Preliminary Sequence Integration and Validation 2 (PSIV) SCRs and comments were delivered, the sequence lead delivered a merged background sequence containing Inertial Vector Propagator/Star ID commands, updated PSIV2 IEB loads were delivered, then processed by the command data subsystem and sequence leads for a final release. The FSIV SCR approval meeting will be held next week along with the FSIV sequence approval meeting.


Solar Conjunction Experiment #2 ended last Tuesday with the Ka-band Translator (KaT) frequency still in its bad region. As a result, the Project has approved an additional period for continuing recovery attempts for the KaT. One condition is that real-time commands may not be used due to the current command moratorium. The suite of Ka-band equipment was powered back on and Radio Science Subsystem (RSS) personnel developed a strategy to use the additional passes at DSS-25 from now till August 2.


The Cassini Archive Tracker System (CATS) was demonstrated to users at last week's Science Archive Working Group meeting. Positive feedback was received. Development of the system will continue with releases of new evaluation versions during the next few months.


Training began on the Multimission Image Processing Laboratory (MIPL) Cassini Downlink and Reconciliation Subsystem (CDRS). This is the automated telemetry processing and evaluation process. Training covers starting/stopping of servers, visibility into the processes, manual intervention and configuration of user's accounts and privileges.


A delivery coordination meeting was held for Mission Sequence Subsystem version D9.1



Additional information about Cassini-Huygens is online at http://saturn.jpl.nasa.gov.


Cassini will begin orbiting Saturn on July 1, 2004, and release its piggybacked Huygens probe about six months later for descent through the thick atmosphere of the moon Titan. Cassini-Huygens is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Office of Space Science, Washington, D.C.


Media Relations Office

Jet Propulsion Laboratory

California Institute of
Technology


National Aeronautics and Space
Administration


Pasadena, Calif. 91109.
Telephone (818) 354-5011