Cassini Weekly Significant Events for 11/21/01 – 11/28/01

The most recent spacecraft telemetry was acquired from the Madrid tracking
station on Wednesday, October 24. The Cassini spacecraft is in an excellent
state of health and is operating normally. Information on the spacecraft’s
position and speed can be viewed on the “Present Position” web page:

http://www.jpl.nasa.gov/cassini/english/where/

The most recent spacecraft telemetry was acquired from the Goldstone
tracking station on Wednesday, November 28. The Cassini spacecraft is in an
excellent state of health and is operating normally. Recent instrument
activities include a Radio and Plasma Wave Science (RPWS) High Frequency
Receiver calibration, instruments waking up after the Huygens Probe Relay
test, the Ka-Band Exciter and Traveling Wave Tube Amplifier powering on, and
all instruments going quiet for the Gravitational Wave Experiment (GWE).
Engineering activities taking place onboard the spacecraft this week include
a transition to Reaction Wheel Assembly (RWA) control from the Reaction
Control Subsystem and an RWA unload in preparation for the GWE.

The Cassini Radio Science team began the GWE on November 25. This is the
first prime science objective on the Cassini Program, and will run for 40
days, ending on January 4, with two more opportunities later during the
cruise phase of the mission. The GWE research scientists will use radio
transmissions between Cassini and Earth to search for gravitational waves
measurably warping space between the two, using continuous coverage
throughout the 40-day experiment to maximize the chances of detecting the
extremely weak waves.

The multi-day Probe Relay test was completed this week. The tests were
required to check out the communications link between the Huygens probe and
the Cassini orbiter spacecraft. Using the Goldstone DSS-24 antenna, a series
of signals was transmitted to Huygens, via Cassini, to simulate the stream
of data that will be sent back by Huygens during its parachute descent
through Titan’s atmosphere. This test represented a major step towards the
validation of the Huygens Recovery Task Force design, testing the nominal
mission scenario and several deviations from it. While it will take a few
months to fully analyze the data, initial indications show that all
objectives were successfully met.

A demonstration of uplink and downlink capabilities at the Emergency Control
Center (ECC) was conducted last week and test reports indicate that all
command, tracking, monitor and telemetry data functions worked successfully.
Further testing of the ECC is planned after completion of the GWE.

A Project Briefing was held to review the C31 Science Planning Team
integrated plan. The Program Manager approved the contents of the plan, and
C31 sequence generation will continue into the next phase of the process.
Other Science Planning activities included the Saturn, Cross-Discipline, and
Ring Target Working Teams meeting last week to finish integrating the Tour
segments associated with Orbits 4 through 10

The Imaging Science Subsystem and the Visual and Infrared Mapping
Spectrometer (VIMS) teams delivered various software packages to the
Multi-mission Image Processing Laboratory (MIPL) Integration and Test
organization as a part of MIPL delivery D27. The delivery to Operations will
be in February 2002. The delivery includes software to analyze data policing
losses, extract background, mirror data, and internal housekeeping
measurements from the VIMS Level 1A products, improve validation of
observation description files delivered from the Science Teams, build such
observation description files in order to easily generate test data, and
improve handling of VIMS data when the visible portion arrives before the
infrared.

The Cassini Project scientist and deputy are attending the American
Astronomical Society Division for Planetary Science meeting in New Orleans.
A number of Cassini at Jupiter papers have been presented.

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.