Status Report

NASA Cassini Significant Events for 08/12/04 – 08/18/04

By SpaceRef Editor
August 20, 2004
Filed under , , ,
NASA Cassini Significant Events for 08/12/04 – 08/18/04

The most recent spacecraft telemetry was acquired from the Goldstone
tracking station on Wednesday, August 18. 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 included uplink and execution of a Cosmic Dust Analyzer
(CDA) flight software checkout mini-sequence, memory readouts of the Command
& Data Subsystem action log and non-interfering error log, and uplink of
files to unmask the helium latch valve driver assembly fault protection
monitors and to update the default main engine thrust value from 450 Newtons
to 443 Newtons prior to Orbit Trim Maneuver(OTM) #2, aka the Periapsis Raise
Maneuver (PRM).

Additional files were generated for use in Spacecraft Operations Office
(SCO) testing of a representative PRM in the Integrated Test Laboratory
(ITL). The final PRM will be approved August 19 for uplink and execution
Monday morning August 23. This is the third largest maneuver to be
performed during the mission, and the last planned fully pressurized
maneuver in the remaining tour. The PRM is necessary to move the spacecraft
path well outside the rings at periapsis, about 300,000 km farther away from
Saturn than it was at Saturn Orbit Insertion.

Two previously unknown moons were discovered orbiting Saturn between Mimas
and Enceladus. The moons are approximately 3 and 4 km across and are
provisionally named S/2004 S1 and S/2004 S2. More information regarding
these moons may be found on the Cassini web site.

Products were delivered for official port 1 as part of Science Operations
Plan (SOP) implementation of tour sequences S35 and S36. Kickoff of SOP
Implementation for S37/S38 begins next week.

The aftermarket process for sequence S07 completed this week, and requested
changes were delivered and decision meetings held for both S08 and S09.

A preliminary port delivery was made for sequence S06 as part of the SOP
Update process.

Three sequence change requests (SCR) were approved at an SCR approval
meeting this week as part of the S04 Science and Sequence Update Process
(SSUP). The SSUP is the final process in the development chain prior to the
uplink of the background sequence to the spacecraft. The SCRs included a
pointing change for Imaging Science Subsystem (ISS), sponge bit allocations,
and two ISS memory readouts (MRO). In addition, the Preliminary Sequence
Integration and Validation-2 stripped sub-sequences for S04 have been placed
in the program file repository.

A waiver request disposition meeting and an SCR approval meeting were also
held as part of the development process for S05. Five of the six SCRs were
approved. These included a tweak to pointing to catch newly discovered
cumulous clouds near Titan’s south pole, a change of primary pointing of
four satellite orbit determination observations to catch newly discovered
moons, a pointing correction for a Titan A RADAR observation, addition of
some Ion and Neutral Mass Spectrometer (INMS) resets, and two ISS MROs.

INMS, the Cassini Plasma Spectrometer (CAPS), and ISS have submitted sample
archive data products and supporting documentation for review by the
Planetary Data System Discipline nodes. INMS is including higher-level
products in their archive.

The Planetary Data System and the RADAR team are conducting peer reviews of
archive data Software Interface Specifications since data products are not
yet available. The review includes raw and higher level products.

The subject of this week’s tour plan presentation to the flight team was the
Cross Discipline Target Working team’s plans for tour.

A VIMS science team meeting was held this week in Denver, Colorado.
Presentations were given on anomaly investigations, status of calibration
and decontamination issues, and the proposed changes to the solid-state
recorder library region.

A delivery coordination meeting (DCM) was held August 18 to review SCO
Propulsion Tools version 3.1 and coordinate installation. The only changes
in this delivery are in the Bipropellant System Performance Tool (BSPT) and
the Monopropellant System Performance Tool (MSPT) files to allow outputs to
be published to the program file repository.

A DCM was also held for the Mission Sequence Subsystem delivery of Cassini
Information Management System version 3.2. The software was installed for
operations use the same day. A tutorial and demonstration are tentatively
planned for the instrument teams at an upcoming Science Planning Tour
Process meeting in early September.

Cassini Outreach conducted two NASA workshops at the Girl Scout USA
Headquarters – Edith Macy Conference Center, Briarcliff Manor, NY. Several
“Saturn in your Kitchen and Backyard” activities were demonstrated for the
leaders. Fifty Girl Scout, 4-H trainers, museum program managers and solar
system ambassadors are now armed with a suite of solar system exploration
activities which they will be incorporating into their programs. Cassini
activities were demonstrated and copies of the activities were distributed
to all. These activities can also be found on the Cassini Education pages

For the most recent Cassini information, press releases and images go to .

The Cassini-Huygens mission 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, manages the
Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington,
D.C. JPL designed, developed and assembled the Cassini orbiter.

SpaceRef staff editor.