Cassini Significant Event Report

For Week Ending 02/21/03

The most recent spacecraft telemetry was acquired from the Madrid tracking station on Wednesday, February 19. 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 completion of the Command & Data Subsystem (CDS) flight software Assisted Load Format (ALF) procedure to uplink ALFs to the Solid State Recorder (SSR). Once in place the backup Attitude Control Subsystem (ACS) Flight Computer (AFC) was loaded with new version A8 flight software, and the AFC was swapped to place A8 onto the prime AFC. Then the new backup AFC was loaded with A7 flight software off of the SSR. Additional activities included an update of Trickle Telemetry on the backup AFC, an A8 Flight Software parameter Memory Readout, checkout of the new ACS Telemetry Schedules, an ACS Reaction Control Subsystem checkout, and clearing of the high water marks on both the prime and backup AFCs.

The port 2 merge for C37 has been completed. All SEQGEN products have been posted to the Distributed Object Manager, and an updated time ordered listing, data volume report, and DSN allocation files are on the C37 web site.

All but 3 data files from a collection of ~500 acquired during GWE #2 have been locally archived. Inquires are underway to determine if the missing files are recoverable. The greatly increased speed and efficiency in completion of this task as compared to data acquisition and archiving for GWE1 and the Solar Conjunction Experiment is due to improved data query software installed on the RSS Operations machines prior to GWE2.

The Radio Science Systems Group has launched a redesigned website at The site includes recent news stories relating to radio-science, as well as technical documentation, staff information, mission contributions, and science goals of radio-science.

The Radio Science Subsystem (RSS) team made an initial delivery of archived Gravitational Wave Experiment (GWE) #1 data to the Planetary Data System (PDS) node for radio science (RS) data. The PDS advisor for RS data has made suggestions on how to enhance the quality of the archived data. This delivery by RSS not only fulfills a commitment to deliver the data within one year of the end of the experiment, but it also provides a pathfinder experience for the Cassini project on the process for preparing and delivering archived data. A Visual and Infrared Mapping Spectrometer science team meeting was held this week in Tucson, Arizona.

The Spacecraft Operations Office (SCO) has upgraded the Cassini Operational Reference Encyclopedia (CORE) software to Version 3.1. V 3.1 contains the revised command definitions for the new Attitude Control and Command and Data Subsystem flight software. Installation on the Cassini Web server by Mission Support and Services Office personnel is now complete.

SCO delivered version 8.2 of the Kinematic Predictor/Inertial Vector Propagator tool set. This version contains enhanced flight rule checking and the new algorithms which will support the "Star Identification Suspend" activity to be used during orbital operations.

Science Opportunity Analyzer (SOA) version 3.0 has been delivered to Cassini. This version of SOA will be released in March with the MSS D8 adaptation for PC and Linux, and then again in MSS D9.1 with the latest adaptation for Solaris 7, PC and Linux.

Composite InfraRed Spectrometer flight software version 2.0 was reviewed at a Software Requirements Certification Review meeting, and approved for testing in SCO before uplink to the spacecraft on May 19.

Uplink Operations personnel provided a Cassini Information Management System (CIMS) introductory user training class to members of the Science Planning team, Mission Support and Services Office (MSSO), and SCO. This class is part of ongoing training provided to new Cassini flight team members.

A special demonstration was given of the new prime/rider notification features in CIMS. Principal Investigators, Co-Investigators, Team Leads, Team members, Interdisciplinary Scientists, and others who participate in the Target Working Team and Orbiter Science Team integration effort benefited from learning how to use this science-team-requested capability.

MSSO personnel hosted an Infrastructure Status Review. Some of the topics addressed included current infrastructure and support, planned implementation of project budget guidelines, changes in network infrastructure, upgrades to sustain existing workstations, and upcoming changes to maintenance and support.

Outreach reported that the Cassini web development team has launched an "Image of the Week" campaign. Each week a new image will highlight a different aspect of Cassini's journey to Saturn. Images will rotate between categories as diverse as mission highlights, historical photos, mission and spacecraft technology, and outreach activities. Check out the latest image on the main web site (

Additional information about Cassini-Huygens is online at

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.

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