Cassini Update - September 23, 2005

Cassini Significant Events
for 09/15/05 - 09/21/05

The most recent spacecraft telemetry was acquired Wednesday, September
21,
from the 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
http://saturn.jpl.nasa.gov/operation...t-position.cfm .

Thursday, September 15 (DOY 258):

Yesterday Cassini passed apoapsis and the start of orbit #15. During
this
near-apoapsis period, the Magnetospheric and Plasma Science (MAPS)
instruments will conduct a campaign to locate dawn-side magnetospheric
boundaries and to observe plasma waves on the magnetospheric boundary
at
various radial distances, as well as continuing to survey the
magnetosphere.

As was reported last week, science data was lost as the result of an
improperly set flag preventing the spacecraft from writing to or
reading
from the A side of the solid state recorder (SSR). Commands were sent
to
the spacecraft today to re-enable SSR-A data recording. Telemetry
confirmed
that the files were received by the spacecraft. Now we wait for a
normal
data collection period and confirmation that all is well when that data
is
played back over tomorrow's pass.

Friday, September 16 (DOY 259):

A press release with Radar images displaying an apparent shoreline on
Titan
has been issued. Hints are evident that this area was once wet, or
currently
has liquid present. For the full press release and access to the
images go
to: http://saturn.jpl.nasa.gov

The Spacecraft Operations Office (SCO) sent commands to the spacecraft
to
load Composite InfraRed Spectrometer (CIRS) flight software Version 4.0
into
the non-default partitions of both SSRs. Checkout of this software is
planned for mid October.

SCO reported that they were able to verify that SSR-A was the prime SSR
during last night's observation. This means that we are able to
successfully command a swap to SSR-A to record data, and we have
regained
the use of both SSRs.

The flight team is gearing up for Orbit Trim Maneuver (OTM) #33. The
preparation meeting was held last Wednesday, and a go ahead was given
at an
approval meeting today. The OTM files have been merged with the S14
background sequence and all have been released for use by the flight
team.
The maneuver will execute next Monday.

The official port occurred today for the S17 Science Operations Plan
(SOP)
Update process. The merged products are currently being run through
the
end-to-end pointing validation software by ACS. The Project Briefing
and
Waiver Disposition Meeting is scheduled for Wednesday, September 28.
The
SOP Update product is handed off to the sequence leads on Friday,
September
30.

Monday, September 19 (DOY 262):

On Friday, a kickoff meeting was held for a Live Update to execute on
DOY
266-269. A final orbit determination solution was released on Sunday,
and
today at the Go/No Go meeting it was decided that the update was still
necessary but only for three Tethys vectors for DOY 266 and 267. When
approved, the files will be uplinked to the spacecraft on Thursday,
September 22.

A Hyperion and Tethys science preview meeting was held to present the
instrument observation plans and science for the upcoming flybys.

Orbit trim maneuver #33 (OTM-33) was successfully completed today.
This
apoapsis maneuver sets up Cassini's trajectory for the flyby of
Hyperion on
September 26. The main engine burn began at 11:00 am PST. A "quick
look"
immediately after the maneuver showed the burn duration was 176.3 sec,
giving a delta-V of approximately 27.8 m/s. All subsystems reported
nominal performance after completion of the burn.

At a Delivery Coordination Meeting SCO delivered version 11.1 of the
Inertial Vector Propagator (IVP) software. This update was
specifically
released to fix issues related to the LIVE_IVP_UPDATE features. There
are
four outstanding test reports written against the released IVP software
version V11.0 for problems encountered during Live IVP Update
activities.

Tuesday, September 20 (DOY 263):

The OTM-34 preparation meeting was held today.

Cassini Outreach presented a poster on "Reading, Writing, and Rings" at
the
annual conference for the Astronomical Society of the Pacific meeting
in
Tucson, Arizona. The meeting was held September 14-16, 2005.
Approximately
350 members of the astronomy education community attended.

As part of the science observation activities this week, the
Ultraviolet
Imaging Spectrograph (UVIS) performed a number of mosaics of Saturn's
inner
magnetosphere. In addition, the Imaging Science Subsystem (ISS) took
images of Mimas, Enceladus, Tethys, Dione, Rhea, and Iapetus to
continue to
map the various satellite longitudes at various phase angles. The
other
Optical Remote Sensing (ORS) instruments acquired data on these
satellites
as well.

Wednesday, September 21 (DOY 264):

The final sequence products for S15 have been posted to the Program
file
repository and are available for review. The sequence approval meeting
will
be held on Tuesday, September 27, with uplink of the background
sequence and
Instrument Expanded Blocks (IEB) beginning on October 3.

A Radar image of a shoreline on Titan was Astronomy Picture of the Day
today.

An encounter strategy meeting was held for OTMs 35-37, and flybys
Hyperion 1
and Dione 1.

Wrap up:

Check out the Cassini web site at 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.