10 Aug 2001
(Source: Jet Propulsion Laboratory)
Cassini Weekly Significant Events for 08/02/01 - 08/08/01
The most recent spacecraft telemetry was acquired from the Madrid tracking station on Wednesday, August 8. 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, http://www.jpl.nasa.gov/cassini/english/where/.
Recent spacecraft activities include the conclusion of a Magnetospheric and Plasma Science observation, a Radio and Plasma Wave Science (RPWS) High Frequency Receiver Calibration, powering off the Composite Infrared Spectrometer, and an autonomous memory load partition repair of Solid State Recorder-B.
The third and final of the instrument muting tests was completed this week. This test puts Cassini in a position to perform future Probe Checkouts with the instruments placed in a sleep state and having their Bus Interface Unit's transmission port 'muted'. Prior to these tests, Probe Checkouts required the Cassini instruments to be powered off for the duration of the activity. This new capability will allow the instruments to avoid incurring an undesired cycle as they are powered off and on again.
In support of the C28 sequence process, the "b" version of the C28 sequence products was released, as was the draft package for the Preliminary Sequence Integration and Validation meeting. A meeting was held to define the Integration Test Laboratory (ITL) simulation support for Flight Software Normalization activities for the Cosmic Dust Analyzer (CDA) and Visual and Infrared Mapping Spectrometer. Also discussed were the results of the successful instrument mute tests and the corresponding impact on C28 testing.
A preliminary package of the Command and Data System Version 9 Flight Software was delivered to the ITL for Huygens Probe relay testing. Probe relay testing has begun in subsystem mode with this new build of the flight software.
The entire set of modules for Mission Sequence Subsystem (MSS) D7.6 has been successfully tested both individually and in small groups by the ITL and High Speed Simulator, and an integrated retest is planned for later this week in preparation for the MSS D7.6 delivery.
The CDA Remote Terminal Interface Unit (RTIU) has been successfully tested, and the new RTIU for RPWS is scheduled to begin testing later this week. The RTIU converts the 1553 real-time instrument data interface to an Ethernet interface for data processing and performance testing with the instrument engineering model.
An on-line Risk Management Tool has been completed for Cassini. Mission Assurance has begun the process of entering data from the Significant Risk List, for risk tracking and assessment. Following a few additional modifications and data entry, the tool will be rolled out for use by the Cassini Risk Team.
A delivery review for the Advanced Multi-Mission Operations System V26.2 release was held this week. This version implements necessary capabilities for the Gravitational Wave Experiment.
The Program Review Plan has been updated and distributed to the flight team for review by Mission Assurance. The plan reflects the high-level review process to assess readiness for SOI, probe relay, and Saturn tour operations, and includes an integrated schedule of program level reviews.
The Cassini Design Team met to collect comments from Cassini personnel on the review process for the Ground Data System and Tour Downlink Operations Concepts reviews. These "lessons learned" comments are being collected by System Engineering for evaluation and implementation in future reviews.
The Mission Planning team held a review of the Cassini navigation tracking requirements. Topics included having ranging "on" at all times as a default, reductions in the 2-way Doppler requirement, and alternative solutions to a requirement that one third of all Cassini DSN support come from the Madrid tracking station.
A Cassini image of Jupiter is featured in the September issue of Sky and Telescope Magazine.
Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.
Cassini Mission to Saturn and Titan
Jet Propulsion Laboratory
California Institute of Technology
National Aeronautics and Space Administration