23 Nov 2001
(Source: Jet Propulsion Laboratory)
Cassini Significant Events 11/15/01 - 11/20/01
The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Tuesday, November 20. The Cassini spacecraft is in an excellent state of health and is operating normally. Recent instrument activities include a Radio and Plasma Wave Science (RPWS) High Frequency Receiver calibration, and the Visual and Infrared Mapping Spectrometer (VIMS), Imaging Science Subsystem (ISS), Cosmic Dust Analyzer, Magnetospheric Imaging Instrument and RPWS instruments going to sleep mode for the Probe test. Engineering activities taking place onboard the spacecraft this week include an update to the Attitude Control Subsystem (ACS) Ka-Band and X-Band body vectors. A minisequence was uplinked that will allow RPWS to operate during the upcoming Gravitational Wave Experiment (GWE).
The multi-day Probe Relay test began this week. The purpose of this series of tests is to validate parts of the revised Cassini-Huygens mission plan, in particular the new parameters of the telecommunications link between the Probe and the Orbiter. The tests are designed to examine the system's robustness to small variations in the communications link that have not been accurately modeled on the ground. Testing involves joint ESA-NASA teams at NASA's Goldstone DSN facility, at the European Space Operations Centre (ESOC) in Darmstadt, Germany, and at the Cassini Mission Operations Center at JPL. Four of five tests have been completed, and an initial assessment of the results indicates no problems with telecommunications for the revised mission plan.
Radio Science held a System Assessment Meeting (SAM) to determine the readiness of the Radio Science System to support the GWE. The resolution of the SAM was that the Cassini Program is ready to conduct the GWE. Also in preparation for the GWE, Radio Science attended a delta design review for the Cassini DSS-25 Upgrade Task. This delta-review closed out several action items from September's initial review.
Mission Assurance completed an extensive review of the Cassini Uplink Process, with emphasis on process and procedural improvement. The process is very thorough and well documented. Existing procedures are currently under review for updates. Refinements will be discussed and incorporated into individual procedures over the next month. Flight Team training and re-certification will be scheduled following completion of the documentation updates. The Multi Mission Image Processing Laboratory (MIPL)/ Instrument Operations team completed implementing and testing of software in preparation for MIPL delivery 27. This software includes updates to both ISS and VIMS product generators; new programs to support identification of policed data and VIMS cube backplane contents; and support for Cassini to use existing MIPL Spacecraft, Planet, Instruments, C-matrix, and Events kernel programs.
Mission Assurance attended the Ensure Mission Success Workshop. The purpose of the workshop was to review high level processes and practices, with the intent of establishing a set of institutional Flight Practices. This workshop focused primarily on Systems Engineering and Mission Assurance, and a follow-on workshop is scheduled for February 2002 to address other areas. A review was held for the Modules and Target Options Requirements of the Mission Software System (MSS) D8 delivery. There was very good participation by the customers, and while some Requests for Action were submitted, none poses any problems to the MSS D8 schedule. This review closes a major open item for proceeding with the D8 delivery, and the MSS development team expressed appreciation for the support from the customers and Project in general in making the review a success.
Twenty-six papers related to Cassini's flyby of Jupiter are being presented at the upcoming Division for Planetary Science of the American Astronomical Society meeting in New Orleans. Four sessions have been devoted to the topic of Galileo and Cassini at Jupiter. In addition, a series of eleven papers on Cassini's flybys of Venus and Earth will be appearing in the December issue of Journal of Geophysical Research. This issue will probably be out in mid-December, following the American Geophysical Union meeting in San Francisco.