Cassini Significant Event Report

For Week Ending 09/29/00

The most recent spacecraft telemetry was acquired from the Goldstone
tracking station on Wednesday, 9/27. 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.


This week saw a number of activities for the Radio Science Subsystem (RSS).
Activities included a repeat of the Instrument Checkout #1 (ICO) RSS Quiet
Test, an Ultra-Stable Oscillator (USO) characterization, a boresight
calibration, and a High Gain Antenna (HGA) pattern calibration.


The Quiet Test allowed the RS Ops Team to determine if the other
instruments' motions could be detected in the Radio Science data. Periodic
USO characterizations allow the RS Ops Team to track and monitor the USO
frequency and behavior over time. The boresight calibration allows the
Ops Team to determine the peak of the Ka-band and X-band antennas. The
HGA Pattern calibration allows the Ops Team to create a "map" of the
antenna gain. Good characterization of the signal at various orientations
is necessary to analyze radio occultation data to be gathered later in the
mission.


Additional activities this week included an AACS SRU calibration and a
Reaction Wheel Assembly (RWA) momentum unload.


Preliminary sequence products were released for Cruise 23, and a
Simulation Coordination Meeting was held prior to sequence testing in the
Integrated Test Laboratory (ITL). Testing of the Cosmic Dust Analyzer
(CDA) in the ITL is going well. Instrument Operations (IO) users of
telemetry processing capabilities at the Multi Mission Image Processing
Laboratory (MIPL) ) spent a week running testbed and ITL data through the
system for the Imaging Science Subsystem (ISS) and Visual and Infrared
Mapping Spectrometer (VIMS).


ISS and VIMS Fomalhaut data have been processed and delivered to
University of Arizona. The instrument teams used the software and
hardware environment at MIPL that will be used to support Jupiter. In
addition, VIMS completed analysis of data from the VIMS Flight Software
test back in June.


The Cassini and the Huygens programs held a series of technical
interchange meetings at JPL this week. Topics discussed included a
briefing on the Probe Relay link performance, a favorable decision on the
proposal to allow MAPS instruments to remain on and in sleep mode during
Probe checkouts (pending successful ground and flight tests), and a review
of the second Titan flyby probe mission opportunity. Additionally, the
Spacecraft Operations Office held an initial design review for the Probe
Relay sequence. Attending the review were Cassini and Huygens personnel
and other engineers from JPL. The review was very successful in the
exchange of detailed information on the relay sequence and in establishing
a baseline design which met Huygens mission requirements


Mission Planning has finished a review of post-Jupiter Spacecraft
Consumables with Spacecraft Office, Science, and Uplink personnel. After
comments are incorporated, the information will be presented as consumable
constraints at the Mission Planning post-Jupiter Activities Scoping
meetings to be held in October and November.


Uplink Operations (ULO) personnel presented a revised (shorter) schedule
for Sequence Virtual Team (SVT) activities to the Cassini Design Team
(CDT). The revised schedule eliminates the existing development schedule
overlap, allowing a reduction in operations staffing.


A review briefing was held for the requirements and design of the Deep
Space Network (DSN) portion of the ground system for the Tour phase.
Discussion focused on DSN Radio Science and Network Simplification Project
(NSP) implementations. The Mission Support & Services Office (MSSO) has
published a draft Functional Requirements Document / Functional Design
Document (FRD/FDD). A final will be produced after the Design and
Requirements review to be held next week. All teams participated in a
Cassini FY' 01 Budget Strategy Planning meeting.


The Navigation Ancillary Information Facility (NAIF) completed updates to
the Spacecraft, Planet, Instruments, C-matrix, and Events kernels (SPICE)
tutorial package. A collection of about 35 tutorials covering many
aspects of the SPICE ancillary information system is available to Cassini
science and engineering users on the NAIF FTP server.


Cassini outreach, with representatives of Galileo and the Goldstone Apple
Valley Radio Telescope project (GAVRT), conducted a training web chat for
members of the Solar System Ambassadors program on the upcoming Jupiter
flyby.



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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Jet Propulsion Laboratory

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