Significant Event Report for Week Ending 8/4/2000

Cassini Significant Event Report

For Week Ending 08/04/00

The most recent spacecraft telemetry was acquired from the Goldstone
tracking station on Tuesday, 08/01. The Cassini spacecraft is 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 final activity for C21 was Probe Checkout #6. Preliminary results
indicate the checkout went as expected with no data outages reported. This
activity represents the first time Cassini has used Deep Space Station (DSS)
14 for operational support since X-Band uplink became available.

During the checkout, Instrument Operations (IO) and Mission Support and
Services Office (MSSO) personnel performed a test of the Virtual Private
Network (VPN) tunnel over the Internet using live spacecraft telemetry.
The test used the same procedures that are used in actual operations,
including the Science Operations and Planning Computer (SOPC) data grab
script, to transfer the telemetry from JPL to the Radio and Plasma Wave
Science Subsystem site (RPWS) at University of Iowa.

After Probe Checkout, C21 deregistered on board the spacecraft. For the
remainder of the C21 time period until C22 registers in September, all
regularly scheduled maintenance activities will be conducted via real time
commands.

This week the Spacecraft Operations team began a four-week task of
switching to a new version of Command & Data Subsystem Flight Software
(CDS FSW), Version 7.0_011.

The software was uplinked to the spacecraft and stored in the Solid State
Recorder-B (SSR-B). Next, new flight software called Emergency RAM load
(ERAM) was uplinked to the spacecraft. This uplink involved over 100
files with the retransmission of only one file required. The ERAM load is
intended to replace Programmable Read-Only Memory (PROM) as a quicker and
more efficient means of loading CDS Flight Software from the ground.
SSR-A was then turned on.

ERAM was used to facilitate "cold-booting" the back-up, or on-line, CDS to
Version 7.0_011 from SSR-B. Finally, additional real time commands were
sent and SSR-A was "embraced" by the on-line CDS and partitioned properly.
Version 7.0_011 is operating nominally in the on-line state and its
activation as Prime remains on schedule for August 9th.

The preliminary Sequence Change Request (SCR) Approval Meeting was held
for the Cruise 22 sequence.

C23 has passed its third and final input port as part of Science Planning
Virtual Team (SPVT) development. SPVT activities for C23 will conclude
August 14.

Representatives from the Uplink Operations Team (ULO) and System
Engineering (SE) traveled to the Southwest Research Institute (SWRI) to
participate in a two-day review of the Cassini Information Management
System (CIMS). Special emphasis was directed toward the physical database
table design, data field security, and how user authentication will be
integrated into the overall Cassini GDS design.

A Software Review Certification Requirements meeting (SRCR) was held for
Cassini Plasma Spectrometer (CAPS) FSW. This delivery contains a patch to
correct the unexpected noise counts found in data during low voltage
operations and CAPS Data Processing Unit (DPU) reset.

System Engineering has produced a Jupiter Integrated Schedule covering
activities for both operations and development. This schedule is being
used as a tool to maintain Flight Team preparedness to support Jupiter
events for sequences C22 through C25.

Cassini Outreach participated in the training sessions for Solar System
Educators, commencing this week and continuing through Saturday. Solar
System Educators are master teachers who will return to their communities
and train other teachers in the use of educational materials developed by
solar system exploration missions.

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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