Significant Event Report for Week Ending 4/21/2000

Cassini Significant Event Report

For Week Ending 04/21/00

The Cassini spacecraft has successfully completed its passage through our
solar system's asteroid belt located between Mars and Jupiter. This makes
Cassini the seventh spacecraft ever to fly through the asteroid belt. The
spacecraft began the crossing in mid-December and while en route obtained
images of asteroid 2685 Masursky. The most recent spacecraft telemetry
data acquired from the Canberra tracking station on Wednesday, 19 April
indicates Cassini remains in an excellent state of health and is operating
normally. The speed of the spacecraft can be viewed on the "Where is Cassini Now?" web page.

The C19 background sequence was uplinked this week and began execution.
Activities included a reaction wheel momentum dump, clearing of the high
water marks, a fault protection log pointer reset, a Solid State Recorder
pointer reset, uplink, execution and playback of the Radio Science
Subsystem (RSS) High Gain Antenna (HGA) mini-sequence, active Inertial
Vector Proprogation (IVP) vector update of the attitude control system, and
decontamination of the Cosmic Dust Analyzer instrument. The RSS operations
team reported that everything went well for both the X-band and Ka-band
calibrations.

The C20 Preliminary Sequence Integration and Validation package was
released for review and a walkthrough held for the Sequence Test Procedure.

System Engineering coordinated a kick-off meeting for the Mission Support
Services Office (MSSO) to clarify the tasks performed by the System
Administrators (SA) and the Customer Adaptation Team (CAT) for operational
configuration of workstations. The intention is to develop a baseline
procedure to improve coordination between the two teams.

The Science Operations and Planning Computers are now ready to ship to two
distributed instrument operations sites (CIRS and RPWS) and the Huygens
Probe Operations Center.

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.

Media Relations Office

Jet Propulsion Laboratory

California Institute of
Technology

National Aeronautics and Space
Administration

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