20 Jul 2001
(Source: Jet Propulsion Laboratory)
Cassini Weekly Significant Events for 07/12/01 - 07/18/01
The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Monday, July 16. 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 a clearing of the Attitude and Articulation Control Subsystem (AACS) Highwater Marks, a Magnetospheric Imaging Instrument (MIMI) Low Energy Magnetospheric Measurement Subsystem (LEMMS) sensor power cycle, and a Radio Frequency Subsystem (RFS) static phase error test. The Reaction Wheel Assembly (RWA) system was unloaded and powered off, and the spacecraft switched to Reaction Control Subsystem (RCS) control as planned. As part of a Periodic Instrument Maintenance activity, the Radio Science Subsystem (RSS) team executed a High Gain Antenna (HGA) boresight calibration and Ultra Stable Oscillator (USO) characterization. The Radio and Plasma Wave Science (RPWS) instrument performed a High Frequency Receiver (HFR) calibration, and the Ultraviolet Imaging Spectrometer (UVIS) performed two interplanetary hydrogen surveys. The Imaging Science Subsystem (ISS) successfully executed its first observations of Saturn along with some star calibrations, and the Visual and Infrared Mapping Spectrometer (VIMS) performed a Pleiades observation.
The Instrument Operations/Multimission Image Processing Laboratory (IO/MIPL) team created and delivered 362 ISS image products of Saturn and stars. The main body of Saturn is about 40 pixels across in the Narrow Angle Camera (NAC) image, and about 90 pixels across when Saturn's rings are included. Titan is also visible and was calculated to be 1.6 pixels across. For comparison, if the NAC were viewing Saturn from Earth, the main body would be about 16 pixels across. Additionally, IO/MIPL created and delivered 220 VIMS cube products of stars.
The Huygens Mission Recovery Task Force (HRTF) held its eighth meeting at the European Space Research & Technology Centre in Noordwijk, Holland. The agenda for this last meeting was to prepare the final report and to consolidate follow-on actions for the JPL and European Space Agency (ESA) teams which will implement the new Huygens mission.
The Attitude Control Flight Software Development team delivered version A8.3.2 of the AACS Flight Software (FSW) to the Integrated Test Lab (ITL) for further testing. This is the second point build for A8.3, which is the FSW build the Spacecraft Operations Office (SCO) is using for critical sequence development.
The VIMS team delivered version 4.1 FSW to the Project Software Library. An ITL test of the newly delivered flight software was conducted to produce data to validate the new MIPL ground software that will process data generated by the FSW. Analysis of the data processing is underway.
An in-depth Critical Design Review (CDR) of Cassini Tour Downlink Operations Concepts was held as the first in a series of reviews to present Cassini readiness for Tour. Additionally, a dry-run presentation was held in preparation for the next CDR, which will review the Cassini Ground Data System.
System Engineering and MSSO personnel worked with the Cassini Information Management System (CIMS) developers to identify several new procedures to increase user access capabilities to the CIMS Web Server.
A kaleidoscopic movie made from about 1,200 Jupiter images taken by Cassini revealed unexpectedly persistent polar weather patterns on the giant planet, and was featured on the CNN website at:
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