Cassini Significant Event Report

For Week Ending 06/27/03

The most recent spacecraft telemetry was acquired from the Canberra tracking station on Wednesday, June 25. The Cassini spacecraft is in an excellent state of health and is operating normally. June 24 marked the four-year anniversary of Cassini's Venus 2 flyby. Information on the spacecraft's position and speed can be viewed on the "Present Position" web page.

Instrument activities this week for Radio and Plasma Wave Science (RPWS) included a High Frequency Receiver calibration, conclusion of the Saturn orbit insertion cyclic test, execution of a Solar Conjunction Experiment cyclic, and an Instrument Expanded Block (IEB) exercise. The Composite InfraRed Spectrometer was woken up to perform a functional test and load of IEBs.

Cassini has entered Superior Conjunction with the Sun-Earth-Probe angle at 5.0 degrees. Minimum separation of 0.344 degrees will be reached next week.

Two sequence change requests (SCR) were submitted as part of the C39 sequence development activity. Both were approved at an SCR approval meeting held this week.

Participating teams submitted all Cassini Information Management System inputs for C40. This was followed by a kickoff meeting to begin the Science Planning Team process.

Events this week for the S14 Science and Sequence Update Process (SSUP) Verification and Validation (V&V) activity included generation and distribution of new Sequence Phase List of Ancillary Files, Pointing Design Tool configuration, SEQGEN data configuration, ephemeris, geometric, and rider epoch files, processing of IEB loads by CDS for loading to the SSR, and release of a fully merged S14 background sequence. This version of the sequence will serve as the basis for the stripped subsequences in the Preliminary Sequence Integration and Validation part 2 process.

A V&V status meeting was held to review current activities, and any schedule changes. As a result of the on-going S14 uplink V&V exercise, potential changes to the SSUP document have been identified.

The Planetary Data System Small Bodies Node representative met with the Cosmic Dust Analyzer (CDA) High Rate Detector (HRD) Co-Investigator last week in Chicago to finalize the HRD component of the CDA archive plan. The archive SIS will be updated with new products generated from the HRD data.

Visual and Infrared Mapping Spectrometer flight software (FSW) version 7.1, Cassini Plasma Spectrometer FSW version 4.0, and Ion and Neutral Mass Spectrometer FSW version 6.0 were delivered to the Project Software Library (PSL). The Spacecraft Operations Office also delivered Reaction Wheel Bias Optimization Tool (RBOT) V1.0. to the PSL. RBOT is designed to compute the Reaction Wheel Assembly (RWA) bias to accomplish RWA momentum management, and optimize consumption of RWA resources.

Radio Science Subsystem (RSS) personnel concentrated this week on characterizing the anomalous behavior of the Ka-Band Translator (KaT) for the on-going Solar Conjunction Experiment #2. The KaT continues to operate in its bad region. Several attempts to correct this by power cycling the KaT have been unsuccessful. History and current status were presented this week to the Cassini Project Manager, staff, and Huygens Probe representatives. The Project approved a request to turn on the S-Band Transmitter pending receipt of a statement from Alenia, the Italian manufacturer of the KaT, or ASI, supporting the expected thermal change. The necessary cognizant engineers will be available next week. In the meantime, RSS personnel are working on preparing a data package to provide to Alenia. On a positive note, monopulse tracking seems to have improved, and coherent Ka1 and X-band data data collection was mostly nominal except for a few outages over Goldstone due to the X-band transmitter tripping off, Radio Science Receiver problems, and monopulse throwing the antenna off point.

A delivery coordination meeting was held for the Science Opportunity Analyzer (SOA) version 9E for PC Windows, and Linux platforms. This is an intermediate delivery until Mission Sequence Subsystem D9.1.1, which will include new SOA, CORE, and Cassini adaptation becomes available.

A Cassini Information Management System (CIMS) developer presented a tutorial on how to use eXtensible Style sheet Language for Transformations (XSLT) to read the CIMS XML files and convert them to any format. This allows users to automate some functions that previously had to be done manually. This was followed by all-day workshops on Wednesday and Thursday to finalize the CIMS requirement for performing a Science Planning Attitude Spread Sheet - Spacecraft Activity Sequence File comparison.

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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