Cassini Significant Event Report

For Week Ending 06/13/03

The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Monday, June 11. 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 calibrations, uplink of the Radio Science Subsystem (RSS) Ka-band Exciter and Ka-band Traveling Wave Tube Amplifier power-off that will execute this Friday, uplink and execution of the Composite InfraRed Spectrometer (CIRS) flight software checkout and data policing overlay, uplink of CIRS Instrument Expanded Blocks (IEB) to the SSR, and uplink and execution of an Ultraviolet Imaging Spectrograph SSR IEB Library Test.

Additional activities included uplink of commands to deregister a program residing on the sequencing region followed by a CDS memory readout, deregistering of the Mission Sequence Subsystem (MSS) D8.0 on board modules, and clearing of the ACS high water marks.

The sequence development process for C38 concluded this week. Last week the "D" version of the C38 background sequence was approved for uplink. A command approval meeting was held this week for an RPWS IEB load to the SSR, the MSS D9.0 modules, and the C38 background sequence. All three files were subsequently uplinked to the spacecraft. C38 begins execution on Saturday June 14.

A Subsequence Generation (SSG) Sequence Change Request (SCR) approval meeting was held as part of the S14 Science and Sequence Update Process (SSUP) Verification and Validation (V&V). SCRs received by the deadline were dispositioned. In addition, detailed subsequences were submitted by all participating teams, comments submitted on the delivered subsequence, closure provided for assigned Science Planning Liens and Actions Table items, and IEBs submitted that will be sent in the background sequence along with any necessary trigger Immediate/Delayed Action Programs. The second SSUP V&V status meeting was also held this week. Agenda items included a review of last week's comments/questionnaire responses and the past week's work for SSUP V&V, including the SCR meeting and process, subsequence inputs, upcoming IEB submission, and process.

Multi Mission Image Processing Laboratory personnel are investigating the impact of the lack of CDS channelized housekeeping data. This change in available data policing information will result in either a software redesign, or less information relayed to the Science Teams, or both.

The task to identify instrument noise events in time is now looking at Visual and Infrared Mapping Spectrometer (VIMS) operations. A dialog was begun with VIMS team members to define the timing of shutter and mirror movements during the various operational modes.

RSS personnel are preparing to support the descoped activities for Solar Conjunction Experiment #2 beginning 15 June. A test pass will be performed at Goldstone on 12 June.

Cosmic Dust Analyzer pointing strategies during both observation periods and downlinks, and DSN weekly maintenance, what it is, what it's trying to prevent, why it needs to be every week, followed by some discussion of its effect on Cassini tracks during tour were covered at this week's Mission Planning Forum.

Volume 104, Issue 1-4e of the Space Science Reviews publication is devoted to 16 papers on Cassini and the Huygens Probe. Space Science Reviews is an international journal containing invited review papers on space science, defined for this purpose as scientific research carried out by means of rockets, rocket propelled vehicles, and partly also by stratospheric balloons and at observatories on Earth or the moon. The journal is principally concerned with the purely scientific aspects of the subject, but instrumental and technical aspects also receive attention.

June 11th marked Cassini's flyby of Saturn's satellite Phoebe one year from now. The Phoebe flyby occurs less than 1 month before Saturn orbit insertion on July 1, 2004.

The "Cassini at Saturn" section of the web site will begin to be populated in the coming weeks. The first segment, Phoebe flyby, will be posted soon. A detailed tour encounter summary and science goals for each rev will be posted during the summer months.

The initial number of planetariums and museums that have requested a copy of "Ring World", the Cassini planetarium show, currently total 178 in the US, over 300 in Japan, and 5 others world wide. It is expected that this number will grow quickly after museum activity related to Mars opposition passes. It is also expected that requests for the DVD version will far outstrip the show kits. DVDs will be available in October to schools, speaker groups, Girls Scouts, 4H, Space Place, Solar System Ambassadors etc.

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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