Cassini Significant Event Report

For Week Ending 02/20/04

The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Tuesday, February 17. The Cassini spacecraft is in an excellent state of health and is operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" web page located at .

Cassini continues to take data for the first color Saturn and ring approach movies, ultraviolet mosaics of the Saturn magnetosphere, searches for previously undetected satellites, and long integrations of Saturn's rings in the mid-infrared to determine ring composition.

Additional activities include uplink of the second set of Ion and Neutral Mass Spectrometer (INMS) diagnostic flight software, a Magnetometer Subsystem (MAG) boom alignment and calibration, Radio and Plasma Wave Science (RPWS) high frequency receiver calibrations, acquisition of optical navigation images, power-off of the Cassini Plasma Spectrometer (CAPS) Ion Mass Spectrometer sensor and power-on of the supplemental heater, clearing of the ACS high water marks, and a DSN array demonstration.

Instrument Expanded Blocks for Visual and Infrared Mapping Spectrometer (VIMS), CAPS, Imaging Science Subsystem (ISS), Ultraviolet Imaging Spectrograph (UVIS), and Composite Infrared Spectrometer (CIRS) were uplinked to the spacecraft along with the C43 background sequence and a CIRS Mission Sequence Subsystem version D10.1 trigger mini-sequence. C43, the second of the approach science sequences, begins execution on Thursday February 19.

A science allocation planning meeting for development of C44 was held this week. There were four days and almost 3000 MB of additional data bits available to be shared by CAPS, Cosmic Dust Analyzer, CIRS, MAG, Magnetospheric Imaging Instrument, RPWS, and VIMS.

Radio Science Gravitational Wave Experiment #1 data archive volume for the Planetary Data System has been distributed to the Radio Science Team for review. This volume will be used as a template for future radio science archive volumes.

In the last week, 331 ISS images were returned and distributed. So far in C42, 540 ISS images, 52 of them optical navigation images, have been returned. In the last week, 46 VIMS cubes were played back and distributed. So far in C42, 416 VIMS cubes have been received.

The Kinematic Prediction Tool / Inertial Vector Propagator analysis on the port #1 products for tour sequences S23 and S24 were delivered this week. In addition, the development process for Science Operations Plan implementation of S25 and S26 kicked off.

The preliminary port#1 of the Aftermarket process for tour sequence S01 occurred this week.

Mission Planning reported that the INMS team has begun simulating Titan A data and using a JPL generated trajectory in support of an exercise to train for estimating the actual Titan atmosphere during the Ta flyby in support of navigation planning for subsequent flybys. The activity will run for about two weeks. During this exercise, the existing atmosphere model will be modified, the trajectory used, and data to be gathered by INMS during the Ta flyby will be emulated. Then another INMS team will take the simulated data and translate it into an atmosphere model which can be extrapolated to 950 km. This is test #2 of this process. The first test uncovered some problems with the process that have since been corrected.

A delivery coordination meeting was held for Multi-mission Image Processing Laboratory software version D31. An additional delivery will be held for version D32.01 in late March to include updates for a VIMS modification and a telemetry processing option.

A Software Review/Certification Requirements meeting was held for INMS flight software (FSW) version 7.0 The software will be uplinked to the SSR and then to INMS RAM during C44. This is a fully functional FSW build and not part of the diagnostic FSW builds currently operating on the instrument.

Articles posted to the University of Arizona Science and Technology website, CNN interactive, and MSNBC News focused on the study of oceans on other planets. The articles feature Titan and Cassini prominently. For more information go to



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.

Media Relations Office

Jet Propulsion Laboratory

California Institute of

National Aeronautics and Space

Pasadena, Calif. 91109.
Telephone (818) 354-5011