Status Report

NASA Cassini Significant Events for 07/31/03 – 08/06/03

By SpaceRef Editor
August 10, 2003
Filed under , ,
NASA Cassini Significant Events for 07/31/03 – 08/06/03

The most recent spacecraft telemetry was acquired from the Madrid
tracking station on Wednesday, August 6. The Cassini spacecraft is in an
excellent state of health and is operating normally. Information on the
present position and speed of the Cassini spacecraft may be found on
the "Present Position" web page located at .

On board activities this week included the conclusion of the Saturn
Orbit Insertion (SOI) demonstration, conclusion of the command
moratorium period, playback of SOI demo data, uplink and execution of
nominal post SOI demo clean up commands, and instrument reconfiguration
following the demo.

The SOI critical sequence demonstration was an end to end demonstration
of the spacecraft preparation, the eight-day critical sequence, and the
clean-up activities to be performed in June and July of 2004. The
preparations and clean-up activities included both sequenced, and
real-time commands as they are planned for execution in 2004. The
sequence itself was stripped of the main engine firing commands, and
other commands with potentially irreversible effects, and replaced with
"NO OP" commands to make the sequence size match exactly.

The Spacecraft Operations Office (SCO) considered this activity to be
the final verification of the critical sequence capabilities in the
Attitude Control (AACS), and Command and Data System (CDS) flight
software versions uplinked earlier this year. The final capability to
be exercised is the accumulated energy cutoff logic for maneuvers. That
demonstration will be part of Trajectory Correction Maneuver 19B
scheduled for October 2003.

During the final hours of the SOI Demo, the Radios Science Team used the
Radio Science Subsystem (RSS) open loop receiver to track the low gain
antenna (LGA) X-Band signal. Using RSS tools, real-time visibility was
afforded the project to confirm the presence of the signal following
each of the spacecraft turns, progress during the burn, and was used to
verify the last "call home" signal. For SOI, this Radio Science
instrument will become the prime tool for real-time visibility into the
progression of the SOI maneuver.

C39 sequence generation concluded this week with participating
instruments delivering final instrument expanded block (IEB) files,
release and review of the Final Sequence Integration and Validation
(FSIV) products, and uplink approval given for the sequence at the FSIV
approval meeting. IEBs for Cassini Plasma Spectrometer, Ultraviolet
Imaging Spectrograph, and Radio and Plasma Wave Science have been
uplinked for this sequence. The background sequence itself will be
uplinked to the spacecraft next week.

Saturday was the last of the post Solar Conjunction Experiment (SCE)#2
DSS-25 passes that the Radio Science Systems Group has utilized to
characterize the Ka-band Translator (KaT) anomaly. Problems with the
Ka-band transmitter at DSS-25 prevented successful execution the planned

As of last Saturday, the KaT was still in the bad region. The next
scheduled opportunity to attempt KaT recovery begins in mid September
during the RSS Engineering Tests, and quiet test. In the meantime, the
Radio Science team will be evaluating information known to date in
consultation with the KaT manufacturer.

System engineering conducted a wrap up meeting this week for the S14
Science and Sequence Update Process (SSUP) Verification and Validation
(V&V) activity. Topics included a general review and summary of
activities, V&V assumptions and liens, review of some of the open
issues, and discussion of tasks remaining to be performed.

Pointing Design Tool (PDT) developers from the Uplink Operations team
presented a training session on the D9.1 version of PDT.

Mission Assurance convened the quarterly Risk Team Meeting to address
cruise risks this week. Risks were reviewed and re-assessed for changes
to likelihood, impact, or mitigation efforts. The team also discussed
future retirement dates for cruise risks. Those cruise risks which do
not apply to Saturn Tour Operations will be retired after SOI next year.

The application window for new Saturn Observation Campaign members
closes 29 August 2003. 51 new applicants were accepted into the program
during July, bringing the total number of amateur astronomers in the
program to 149.

The Outreach Team attended a workshop on educational techniques for
special needs students at Goddard Space Flight Center. The South East
Regional Clearinghouse (SERCH) hosted the event. SERCH is a NASA broker
and facilitator that provides support in all space science research
areas, "plays matchmaker" between scientists and Education/Public
Outreach programs, and assists in regional distribution of educational
products. At the workshop, Cassini outreach personnel presented a
mission overview and introduced different Cassini education materials.

All Cassini teams and offices supported this weeks NASA Quarterly

As reported on-line at Sky and Telescope, at the 25th General Assembly
of the International Astronomical Union, the Working Group for Planetary
System Nomenclature announced the names of two dozen planetary
satellites discovered since 2000. On the list were 12 Saturnian moons.
The satellites were named for Norse, Inuit, or Gallic giants. For more
information go to

SpaceRef staff editor.