NASA Cassini Significant Events for 05/05/04 – 05/12/04

The most recent spacecraft telemetry was acquired from the Goldstone
tracking station on Wednesday, May 12. 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 http://saturn.jpl.nasa.gov/operations/present-position.cfm .

The final sequence approval meeting was held this week for S01, the first
tour sequence. The background sequence, Ion and Neutral Mass Spectrometer
(INMS) mini-sequence, and instrument expanded block loads have been
processed and radiated to the spacecraft. The sequence will begin execution
on Friday May 14.

Final activities in C44, the last Approach Science sequence, included uplink
and execution of commands to reset the Imaging Science Subsystem (ISS)
narrow and wide-angle cameras, uplink of Reaction Wheel Assembly (RWA) bias
commands to execute in S01, and continuation of C44 science data collection
activities.

Sequence development of S02 continued this week with release for review of
the S02 Preliminary Sequence Integration and Validation 1 (PSIV) background
sequence products, and Sequence of Events /Space Flight Operations Schedule
products with a Saturn Orbit Insertion (SOI) burn sequence merged in for
reference.

The Spacecraft Team completed a second Operational Readiness Test (ORT) on
Saturday, May 9, 2004. This ORT involved Spacecraft Operations, Navigation,
and Uplink Operations (ULO). The goal of the test was to demonstrate that
these teams could recover from an anomalous SOI and perform a large
correction maneuver in less than 3 days. The Navigation analysts were given
simulated SOI Doppler data and the Spacecraft team was given an interrupted
burn with an underperforming engine. Both teams, with ULO support, were
able to diagnose the faults in a timely manner and complete the required
work to get to the nominal Orbit Trim Maneuver 1 time.

Three SOI Critical Sequence regression tests were performed on May 10-12,
2004. These regression tests were to ensure that the Critical Sequence
would work correctly with the two new ACS mask commands. The mask commands
are the response to an ACS fault protection issue that surfaced last month.
All tests were successful.

The ACS team completed end-to-end pointing analysis for tour sequences S27
and S28 as part of the Science Operations Plan Implementation process.
Preliminary port 1 occurred for S29 and S30. The products have been merged,
checked, and reports issued to the teams.

A Project Briefing and Waiver Request Disposition Meeting was held for S03.
All waiver requests were approved. The handoff product has been given to
the Sequence Team for the start of the SSUP process on May 17.

The S05 aftermarket process began this week with an assessment meeting to
discuss proposed changes to the integrated plan. The integration teams will
be evaluating these requests over the next couple of weeks, but initially it
appears that requested changes fit within available resources. A final
decision meeting to disposition the requested changes will be held on May
26.

The total number of ISS images acquired since the start of Approach Science
is now 5855, and the number of Visual and Infrared Mapping Spectrometer
(VIMS) cubes is 781.

Two items were approved this week in an effort to alleviate downstream
workload and increase performance. A request for an update to the Multi
Mission Image Processing Laboratory uplink software is now accepted as it
will assist in reducing workload downstream on ULO, and after evaluation of
Pointing Design Tool (PDT) performance testing, approval was given to
release client-server versions of PDT for Mac and Linux platforms.

Instrument Operations, Science Planning, the Spacecraft Operations Office,
and the Mission Support and Services Office participated in a Saturn Orbit
Insertion (SOI) Playback Assessment Test. The rehearsal was intended to
exercise end-to-end SOI Ground System procedures. Data loading into the TDS
was expedited, to reflect planned SOI operations, making bested data
available to instrument teams within 45 minutes versus 4 hours during normal
operations. Team instrument data accountability reconciled with SCO
Telemetry Input Gap Analyzer & Reporter data accountability and the teams
showed they can easily meet their post SOI 20 hr deadline to evaluate the
release of the SSR.

A delivery coordination meeting (DCM) was held for the ISS Pointing Tool
(ISSPT) V2.5. ISSPT is a program that allows the user to design imaging
observations using the Imaging Science Sub-system on the Cassini spacecraft.
ISSPT allows the user to adjust and optimize camera settings, calculate
image brightness and content based on pointing, and produce an Instrument
Operations Interface output file suitable for building camera command
sequences.

DCMs were held for PGT V9.1 and Mission Sequence Subsystem D10.3.1.

The Cassini Literacy Team hosted a booth at the International Reading
Association convention in Reno, Nevada. Interest in “Reading, Writing, and
Rings” was very high among the teachers in attendance. In addition, several
publishers spoke with the team about Cassini products and incorporating
Cassini images and products in upcoming publications.

A Saturn Observation Campaign member demonstrated the “What Is Synchronous
Rotation?” activity and answered Cassini and Saturn related questions at
Space Day 2004. The event, held at the Udvar Hazy Aerospace Wing of the
Smithsonian Institution’s National Air and Space Museum was part of the
nationwide Space Day event.

Recent images of Titan returned by the Cassini spacecraft may be seen at http://saturn.jpl.nasa.gov In an article in the Honolulu Advisor on May 7, it was reported that
astronomers using Near Infrared Imager of the Gemini North Telescope on
Mauna Kea have observed 10 objects circling Jupiter and four others circling
Saturn providing evidence suggesting that clusters of satellites circling
Jupiter and Saturn may be pieces of asteroid-like objects that were
shattered in collisions early in the existence of the solar system. For more
information go to: http://the.honoluluadvertiser.com/article/2004/May/07/ln/ln03a.html Cassini is a cooperative project of NASA, the European Space Agency and the
Italian Space Agency. The Jet Propulsion Laboratory, a division of the
California Institute of Technology in Pasadena, Calif., manages the Cassini
mission for NASA’s Office of Space Science, Washington, D.C.