Cassini Significant Event Report

For Week Ending 01/19/01

The most recent spacecraft telemetry was acquired from the Goldstone
tracking station on Wednesday, January 17. The Cassini spacecraft is in
an excellent state of health and is operating normally. The speed of the
spacecraft can be viewed on the
"Present Position"
web page.


Phase E of the Jupiter subphase continues this week. Activities included
atmospheric cyclic observations, Ganymede eclipse observations, Ultraviolet
Imaging Spectrometer (UVIS) Io torus observations, Europa observations, and a
UVIS/Hubble Space Telescope aurora observation. Uplinked commands included
the C24 Background Sequence, Radio and Plasma Wave Science (RPWS) High Frequency
Receiver Calibration Immediate/Delayed Action Program, reaction wheel momentum
unload, and Imaging Science Subsystem (ISS) Instrument Expanded Block load.


On Sunday January 14th, the Cruise 24 sequence began execution.
Activities included Narrow Angle Camera (NAC) observations of the Io
torus, Visual and Infrared Mapping Spectrometer (VIMS) ring spectral
observations, ISS 1X2 Movie, RPWS periodic engineering maintenance, and
start of Cosmic Dust Analyzer dust stream collection. Other activities
included uplink of the MIMI memory readout, clearing of the RPWS write
protect bit and AACS clear high watermark.


RPWS personnel report additional bow shock crossings. It appears Cassini
crossed the bow shock (outbound) on day 12 at approximately 14:20. Weak
Langmuir waves were observed afterwards at a frequency of about 9 kHz (1
cm^-3). Instrument personnel have determined that there was an inbound
shock at 2:10 on day 014 followed by an outbound shock at 5:28 on day
015. The solar wind density after the day 015 shock was about 0.8 cm^-3.


The Cassini Instrument Operations (IO) Team and the Multi Mission Image
Processing Laboratory have produced and delivered 19,107 ISS images -
12,715 from the NAC and 6292 from the Wide Angle Camera - and 3,618 VIMS
cubes since Jupiter encounter began.


The Huygens Recovery Task Force met at the European Space Technology
Center (ESTEC) in Noordwijk, the Netherlands on January 10. The team
began by assessing several different options for improving the probe link
performance. These options included improved ground processing and error
correction, changes in both the probe and orbiter flight software, and
changes in the trajectory. Follow-on meetings will be held at JPL during
the week of January 15.


IO hosted the Events Kernel Working Group kick-off meeting, with
participation by Navigation Ancillary Information Facility (NAIF)
personnel and remote site Operations Technical Leads (OTL).


System Engineering continues to coordinate update of the Tour Operations
Concepts. At this week's Cassini Design Team meeting, three of the
downlink science concepts were discussed and open items identified.


A Delivery Coordination Meeting was held for Command Data Base D7E. This
is a new command database which will become active with the delivery of
Mission Sequence Subsystem D7.4 on 1/26/01.


Equipment inventories are being reviewed in preparation for input to the
publication of the Lab wide, NASA directed "Information Technology
Security Plan." This plan is to be completed with Headquarters approval by
the end of fiscal 2001.


Discussions have begun with the scientific journal, Icarus, regarding
publishing a series of Cassini articles over the next ten years.



Additional information about Cassini-Huygens is online at http://saturn.jpl.nasa.gov.


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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