Cassini Significant Events -- for 06/01/05 - 06/08/05

June 10, 2005

(Source: Cassini Project)

The most recent spacecraft telemetry was acquired Wednesday from the
Goldstone and Madrid tracking stations. 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 .

Activities this week:

The main science event this week was the third Radio Science Subsystem (RSS)
Occultation observation. More details on this observation appear in the
June 8 section of this report.

Other activities during this week include a high-resolution study of bow
shocks and other magnetospheric boundaries by the Cassini Plasma
Spectrometer, Radio and Plasma Wave Science subsystem (RPWS), Magnetospheric
Imaging Instrument, and Magnetometer Subsystem (MAG). The Optical Remote
Sensing instruments observed Dione and Titan, worked on identifying the
orbit of newly discovered rings, attempted to detect flashes from
meter-sized interplanetary impacts on the rings, and worked to obtain
thermal measurements of the rings.

Wednesday, June 1 (DOY 152):

A member of the Science Planning team gave a talk to 20 engineers at the
monthly meeting of the Institute of Environmental Science and Technology in
Anaheim, California.

A delivery coordination meeting was held for the Spacecraft Operations
Office (SCO) tools Assisted Load Format (ALF) version 11 and Predict
Generation Tool V9.2.

Members of the Magnetometer Subsystem gave a presentation on recent
Enceladus results at a Cassini internal Tour Science Talk.

The Planetary Data System (PDS) announced the first data release from NASA's
Cassini Mission to Saturn. This release consists of data from the RPWS
instrument from October 1997 through January 2002. The next release of
Cassini data will be July 1, 2005. All available PDS data may be downloaded
from: For further
information about PDS online services, see the PDS home page:

Thursday, June 2 (DOY 153):

The Aftermarket process for the S15 sequence concluded today. The Science
Operations Plan Update (SOPU) process will begin on June 16.

A delivery coordination meeting was held for the SCO tools Kinematic
Prediction Tool (KPT)/Inertial Vector Propagator (IVP) version 11. The
tools will be used in operations after the delivery of the Mission Sequence
Subsystem on June 15.

A Deep Space Mission Systems Delivery Review (DDR) was held for the
Telemetry, Tracking, Command & Data Management system version 29.1.1. No
issues were uncovered. The Mission Support & Services Office will now begin
Cassini testing and will develop a plan for infrastructure installation in
early July.

Uplink Operations sent commands to the spacecraft for the second S11 Live
IVP Update mini-sequence. The mini-sequence will begin execution tomorrow.
A live movable block mini-sequence will be uplinked over the weekend and
will execute on Wednesday, June 8.

Friday, June 3 (DOY 154):

Commands were sent to the spacecraft today to modify the System Fault
Protection Command Loss Timer (CLT) strategy. The CLT limit was increased
from 85 hours - roughly 3.5 days - to 5 days. The limit was increased to
span the duration of the next RSS occultation experiment. The limit will be
commanded back to 85 hours on June 9.

Part of the fault protection system monitors communications with the ground.
If for any reason a command is not received by the spacecraft before the
expiration of the time limit, the spacecraft will assume there is a
"problem", call fault protection, and put Cassini into safe mode until the
"problem" is resolved. This is a common feature on all spacecraft and CLT
commands are sent each time Cassini has a DSN pass to prevent the expiration
of the time limit.

Participating teams delivered files for the official port for the S14
Science Operations Plan Update process. The files will be merged the
beginning of next week.

Monday, June 6 (DOY 157):

An image of Enceladus and Saturn's rings was Astronomy Picture of the day

Members of the Visual and Infrared Mapping Spectrometer (VIMS) team and
Integrated Test Laboratory successfully ran a test of the new SSR region for
VIMS command loads and the updated VIMS and ALF tool software which gets the
load into the instrument.

The Official Port 1 Merge for S14 SOPU is now complete and the products have
been placed in the Program file repository.

Tuesday, June 7 (DOY 158):

Outreach was accepted to give a workshop at the California Science Teachers'
Association (CSTA) in October 2005. The workshop will focus on "Reading,
Writing, and Rings".

A new Cassini poster is due for delivery to Outreach Friday June 10.

Wednesday, June 8 (DOY 159):

The Radio Science Subsystem (RSS) successfully measured the properties of
Saturn's rings and atmosphere by performing an egress radio occultation
experiment. The occultation occurred over Goldstone stations 14, 25, and 26
and Madrid stations 63 and 55. All five antennas supported the entire
observation. Fourteen open-loop receivers were recording simultaneously.
Everything appears to have gone nominally. During the occultation, VIMS and
the Ultraviolet Imaging Spectrograph performed a solar occultation ingress
experiment and the Cosmic Dust Analyzer measured the dust flux and particle
composition during the Enceladus orbit crossing.

An Aftermarket process assessment meeting for the S16 sequence was held
today. This Aftermarket process runs for five weeks and addresses proposed
discretionary changes that require re-integration of the segments contained
in a sequence. At the Assessment meeting, the Project Scientist and
participating teams scope out the proposed changes and determine if they
will fit within the available workforce "budget".

A delivery coordination meeting for the Cassini Archive Tracking System
(CATS) software v3 was held today. CATS is a web application tool that
tracks required archive submissions into PDS, and allows the project and PDS
to accurately and efficiently report on archive submission status. The
software was accepted for delivery and will be in use as the first archive
volumes are completed this month.

Non-targeted encounters of two moons of Saturn - Pallene and Calypso -
occurred today.

In a news release dated June 8, JPL announced the possible discovery of a
Titan volcano that could be a source of methane in Titan's atmosphere.
Images taken in infrared light show a circular feature roughly 30 kilometers
in diameter that does not resemble any features seen on Saturn's other icy
moons. Scientists interpret the feature as an "ice volcano," a dome formed
by upwelling icy plumes that release methane into Titan's atmosphere. The
findings appear in the June 9 issue of Nature.

For more information visit

Today we celebrate the 380th birthday of Giovanni Domenico Cassini. Born
June 8, 1625, Cassini was the first to observe four of Saturn's moons and
discovered what is now known as the Cassini Division in Saturn's rings.

Wrap up:

Check out the Cassini web site at for the latest
press releases and images.

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.