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Significant Event Report for Week Ending 4/20/2001

Cassini Significant Event Report

For Week Ending 04/20/01

The most recent spacecraft telemetry was acquired from the Goldstone
tracking station on Tuesday, April 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.

Recent spacecraft activities included automatic repairs of both Solid
State Recorders (SSRs), an update of the Attitude Control Subsystem (ACS)
default Inertial Vector Propagator (IVP) vector on the SSRs, a Radio and
Plasma Wave Science (RPWS) HFR calibration, and a High Watermark clear.

Final products for the C26 background sequence were released ahead of
schedule in preparation for the C26 preliminary SIV approval meeting to be
held next week.

Tuesday marked the beginning of a week long Cross-Discipline Workshop
sponsored by Cassini Science Planning. The goals of this workshop include
the identification of heavily conflicted periods, the division of the tour
into segments and the creation of Target Working Teams (TWTs). Breaking
the tour into segments will facilitate planning and integration of science
objectives, while the TWTs will help resolve conflicts and develop simple,
integrated observing strategies. A general understanding of the
observations that are planned and desired during the tour will be gained
through a series of presentations from both instrument teams and
discipline working groups. The intent is that the combination of these
presentations will provide the basis for dividing the tour into segments
with common integration issues or conflicts. The segments may be a portion
of an orbit or an entire orbit in a class or family of orbits. The
families or classes of orbits are defined by their unique nature in the
tour (i.e. inclined, magnetotail apoapsis, dayside apoapsis, etc). Each
team and discipline working group will identify families of orbits that
provide the geometrical opportunities desired for specific science

A new version of the Cassini Information Management System (CIMS) software
was installed for Project use this week. A major change in this version
is streamlined security functions.

ULO presented an overview of the current status of the cyclic
functionality (repeated use of user-defined subsets of onboard sequence
commands) at the Science Planning Cross-Discipline Workshop this week.

Systems Engineering supported a Delivery Coordination Meeting for the
Navigation Ancillary Information Facility (NAIF) Toolkit with specific
Cassini-subroutine additions.

System Engineering reported that several downlink concepts for Tour are
now ready for presentation before a review board. Reviews for Cassini
Operations concepts are currently scheduled for May and June of this year.

Version F of the Cassini Anomaly Response Plan has been released for

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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