Cassini Update - March 4, 2005

Cassini Significant Events
for 02/24/05 - 03/02/05

The most recent spacecraft telemetry was acquired today from the
Goldstone
tracking station. 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/operation...t-position.cfm .

Activities this week:

This week we executed Orbital Trim Maneuver #15, wrapped up the S08
background sequence, and started S09.

Science this week included Imaging Science Subsystem (ISS) continued
acquisition of movies of Saturn's southern hemisphere, the Composite
and
Infrared Spectrometer (CIRS) collection of Mid-IR maps showing the
temperature of Saturn's troposphere and tropopause, a CIRS stay-light
calibration, and the suite of Magnetospheric and Plasma Science
instruments
continued their simultaneous low-rate magnetospheric surveys.

Thursday, February 24:

Uplink Operations completed uplinking the remaining Instrument Expanded
Block files for S09.

The Radio and Plasma Wave Science (RPWS) team made its first Planetary
Data
System (PDS) archive submission containing data from the 1999 Earth
flyby.
After completion of a brief PDS validation, this dataset will be
available
to the public through the PDS Plasma Physics Interactions Node.

Today's Astronomy Picture of the Day is an image of Saturn's moon
Enceladus.
You can access "Ski Enceladus" at
http://antwrp.gsfc.nasa.gov/apod/ap050224.html This is the 6th Cassini
APOD
this month!

Tonight and tomorrow night the Cassini Spacecraft Operations Office
Manager
will give JPL Von Karman Lectures on the Cassini Mission to Saturn. In
conjunction, the Saturn Observation Campaign will provide telescopes
and
Saturn views at JPL for the Thursday night talk and in Pasadena for the
Friday night talk.
UPDATE: 400 people stopped for a look at Saturn and Titan, and many
also saw
Mimas, Enceladus, Iapetus, Dione, Rhea and Tethys. About 100 people
showed
up on Friday.

Friday, February 25:

Today the S09 background sequence was uplinked to the spacecraft. The
sequence is ready and waiting for activation on Saturday night. Along
with
the sequence and Instrument Expanded Block files, commands to move the
Cassini Plasma Spectrometer (CAPS) actuator, update the CAPS Electron
Spectrometer high voltage step to 47, and perform an ACS reaction wheel
bias
were also uplinked.

Deep Space Mission Systems delivery of D33 was accepted at a delivery
review
today and was declared operational. Significant upgrades to both uplink
and
downlink software were included for support of ISS and the Visual and
Infrared Mapping Spectrometer.

ISS has completed its analysis of the Integrated Test Laboratory run of
ISS
flight software version 1.4. All data were as expected and no issues
were
found. This test sequence will be executed in-flight in June for final
validation of the updated software.

ISS Support Imaging personnel received a new version of the ISS Science
Team's Pre-commanding Tool. This version has been installed for
testing and
evaluation.

Another Astronomy Picture of the Day - this time "Saturn's Dragon
Storm."
http://antwrp.gsfc.nasa.gov/apod/ap050225.html

Saturday, February 26:

The final activity in S08 was a reaction wheel bias and desaturation.
S09
began execution at 5:46 PM Pacific time. S09 runs for 41 days ending
on
April 8. Key events include six OTMs from 15 through 20, two targeted
flybys - Enceladus and Titan, ten non-targeted encounters - Helene,
Atlas,
two of Tethys, Enceladus, Epimetheus, Mimas, Dione, and Rhea, 54
optical
navigation images will be acquired, and approximately 64.5 gigabits of
data
will be downlinked.

Sunday, February 27:

RPWS performed a Periodic Instrument Maintenance beginning today and
completing on Monday.

Orbit #4 began today as Cassini passed through Saturn apoapse. Apoapse
is
the farthest the spacecraft will pass by Saturn. A new orbit always
begins
and ends with apoapse.

Monday, February 28:

Official Port 1 was completed as part of the Science Operations Plan
Update
for tour sequence S12. The files were merged and the resulting files
made
available for review.

Today the Cassini Project Science Group began a weeklong series of
presentations and discussions.

Tuesday, March 1:

OTM-15 was successfully completed on the spacecraft this evening. This
apoapsis maneuver places the spacecraft on the proper trajectory for
the
March 9, 500 km targeted flyby of Enceladus.

The main engine burn began at 9:59 p.m. PST. A "quick look"
immediately
after the maneuver showed the burn duration was 40.1 sec long, giving a
delta-V of 6.2 m/s.

ACS reported the burn termination was a "nominal complete" with an
accelerometer cutoff. Navigation reported receiving ranging points
before
and after the maneuver. Propulsion indicated the burn was nominal.
Tank
pressures, temperatures, etc, were nominal. Thermal indicated
performance
was nominal and temperatures were recovering as expected. Power margin
throughout the maneuver was nominal. There was no unexpected CDS or
Fault
Protection activity.

Wednesday, March 2:

The Navigation team released a reconstructed Cassini trajectory file
covering the period from December 1, 2004 through January 15 of this
year.
This file contains the spacecraft, probe, planetary, and satellite
ephemeredes and is for use for tour analysis for the period of the
file.

Wrap up:

That's it for this week.

This week there were various articles on Cassini discussing new
discoveries
of wandering and rubble-pile moons, new and clumpy Saturn rings and
ringlets, splintering storms, rainbows on Titan, images of Saturn's
radiation belt, and much more. Be sure to check out the Cassini web
site
http://saturn.jpl.nasa.gov 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.