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Cassini Significant Events
for 05/01/03 - 05/07/03

The most recent spacecraft telemetry was acquired from the Goldstone
tracking station on Wednesday, May 7. 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 .

On board activities this week included Trajectory Correction Maneuver
19 (TCM-19), Probe Checkout 11, High Rate Observations, High
Frequency Receiver Calibrations, an Instrument Expanded Block (IEB)
exercise, and a periodic instrument maintenance all for the Radio and
Plasma Wave Science instrument, uplink of IEBs for Visual and
Infrared Mapping Spectrometer (VIMS), a Cosmic Dust Analyzer (CDA)
absolute turn calibration, and several high water mark clears.

All activities before, during and after the TCM-19 burn executed
nominally, and all telemetry was as expected. The design burn time
was 17.57 seconds. The maneuver terminated with a nominal
accelerometer shutdown after burning for 17.53 seconds.

TCM-19 was the first main-engine maneuver performed in over a year.
The primary purpose for this 1.58 m/s blow down maneuver was to
satisfy the 400-day flushing requirement of the bipropellant
propulsion system.  The maneuver also validated the new main-engine
maneuver block to be used for tour, and the ground processes that
will be used during orbital operations. The block is designed to be
integrated within the tour downlink passes. The ground processes
demonstrated a rapid maneuver design, and uplink of the maneuver on
the same tracking pass upon which the maneuver will execute.
Additionally, several Saturn Orbit Insertion (SOI) maneuver
activities were demonstrated. These were 1) early closure of the
main-engine cover after the burn; 2) use of both dual drive motors
for cover closure; and 3) early turn-on of the oxidizer valve heater
after burn termination.  TCM-19 allowed an opportunity for checkout
of what would otherwise be first-time events during SOI. 

Probe Checkout 11 also executed nominally.  Huygens personnel have
received all data from the checkout, and preliminary analysis
indicates that all Probe instruments are functioning as expected.

Various teams and offices supported this month's Cassini / NASA
Quarterly Review.

The Spacecraft Operations Office (SCO) held a design review for the
Huygens probe release scenario. The scope of the review covered the
final probe-targeting maneuver through the release sequence and
spacecraft attitude recovery. The board, consisting of JPL and
European Space Agency personnel, approved the mission scenario and
release sequence design, and identified no major issues. There were
sixteen requests for further action, which will be closed during the
course of the release sequence development.

An Archive Design Peer Review of the Cassini Plasma Spectrometer
(CAPS), Ion and Neutral Mass Spectrometer (INMS), Magnetometer
Subsystem (MAG), and Radio Detection and Ranging (RADAR) instrument
team archive plans was held this week.  Members of the Planetary Data
System, instrument team representatives, and Instrument Operations
personnel attended. 

A wrap up meeting was held for Science Operations Plan (SOP)
development of tour sequences S17 and S18.  The sequence products
have been archived until August of 2005 when the SOP Update process
will begin for S17. 

SOP Update V&V completed this week, on schedule. Participating teams
have been queried throughout this activity for status and comments on
the processes and tools.   The results have been compiled and will be
presented at the SOP U/D V&V wrap-up meeting next week. As part of
the process, Science Planning hosted a project briefing to outline
the modifications to S14, and to present Uplink Operations with a
package that officially "hands over" the sequence to the Science and
Sequence Update Process (SSUP).

Delivery Coordination Meetings were held for the redelivery of
Mission Sequence Subsystem (MSS) D9.0 On-Board Modules, Kinematic
Prediction Tool / Inertial Vector Propagator V9.0, MSS D9.0.1, and an
update to the command database.  The MSS D9.0.1 Delivery Coordination
Meeting had been postponed one week to accommodate test and
integration of a new command database Version 9D.  Two errors in
Composite InfraRed Spectrometer (CIRS) commands were uncovered last
week while CIRS was testing their V2.0.1 flight software checkout
sequence.  The commands are critical to their checkout and although a
workaround was possible, it was extremely arduous. SCO quickly
produced an updated database, tested, and delivered it.

Cassini Outreach participated in judging High School Science Projects
relating to Earth and Space Science at the Los Angeles County Science
Fair, held at the LA Convention Center, and hosted an educator
workshop on Cassini for 25 master teachers attending a weeklong
training session in Pasadena, California.

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. 

Cassini Outreach
Cassini Mission to Saturn and Titan
Jet Propulsion Laboratory
California Institute of Technology
National Aeronautics and Space Administration

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