Cassini Update - November 20, 2009
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Cassini Significant Events
for 11/11/09 - 11/17/09
The most recent spacecraft telemetry was acquired
on Nov. 17 from the Deep Space Network tracking
complex at Canberra, Australia. The Cassini
spacecraft is in an excellent state of health and
all subsystems are operating normally.
Information on the present position and speed of
the Cassini spacecraft may be found on the
"Present Position" page at:
http://saturn.jpl.nasa.gov/mission/presentposition/ .
Wednesday, Nov. 11 (DOY 315)
Based on analysis of the preliminary data, the
Navigation Team proposed the cancellation of
Orbit Trim Maneuver (OTM) #222, planned to
execute on Nov. 12. This was approved by the
project. NAV also noted that it might be possible
to cancel OTM-223. Cancellation was contingent
upon an update to Enceladus pointing and
agreement by the various instrument teams.
Science Planning performed an OTM cancellation
assessment based on a preliminary spacecraft
ephemeris without the maneuver in it. The results
are very clear: an unplanned Live Inertial Vector
Propagator (IVP) update for Enceladus would need
to be performed should both OTMs be canceled. The
instrument teams completed their evaluation of
the proposed pointing update to Enceladus and
Rhea vectors on DOY 324-325 during the Enceladus
8 flyby period. The unplanned live update is a
go, and OTM-223 has also been cancelled.
In addition to the Live IVP update mentioned
above, Uplink Operations held a kickoff meeting
for the Radio Science (RSS) Enceladus 8 Live
Update Block (LUB) on DOY 324. RSS has evaluated
the most recent data and no updates will be
required to the product developed alongside the
background sequence development in October. These
files will be uplinked to the spacecraft on Nov. 18.
Thursday, Nov. 12 (DOY 316):
A news note on the Cassini Web page highlighted
an image of the massive bright clouds of tiny ice
particles hovering above the darkened rings of
Saturn. The picture was taken on Sept. 22, around
the time of Saturn's equinox, when the icy
particle clouds appeared particularly dramatic
because of the unique lighting geometry of the
equinox period. These levitating icy particle
clouds, which are known as "spokes," have a
radial extent of up to 10,000 kilometers. For the
complete text of the feature link to:
http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20091113/
Judges have selected the U.S. winners for the
Cassini Scientist for a Day essay contest.
Details on the contest, selected essays, and images can be found at:
http://saturn.jpl.nasa.gov/education/scientistforaday8thedition/sfad8thview/
Friday, Nov. 13 (DOY 317):
Science and engineering teams delivered files for
the third and final input port for the S58
Science Operations Plan process. The files have
been merged and released for review. The process
concludes Nov. 30 with the final development
process - the Science and Sequence Update Process -
beginning the following week. S58 execution begins
March 1, 2010.
The S54 sequence concluded and S55 began
execution today at 2009-315T12:44 PST. The
sequence will run for 39 days and conclude on
Dec. 22. During that time there will be two
targeted encounters, one of Enceladus and one of
Titan, and six non-targeted flybys - one each of
Helene, Pandora, Titan, Calypso, Rhea and
Pallene. Six maneuvers are scheduled, numbered 223
through 228.
Science at the start of S55 included observations
for an Optical Remote Sensing Titan cloud
monitoring campaign. Imaging Science then
observed the dark-side of Saturn in search of
lightning, obtained images of the transits of
Titan across Hyperion and Enceladus across Rhea
for orbit determination purposes, conducted
Saturn wide angle camera photopolarimetry
observations, and imaged a couple of stars as
part of a charge transfer calibration.
Magnetospheric and Plasma Science (MAPS)
instruments continued with the solar wind-aurora
campaign, and began a magnetospheric boundaries
campaign. The Ultraviolet Imaging Spectrograph
performed observations as part of a large
campaign to measure Saturn's magnetosphere at
apoapsis, and took a distant look at Enceladus to
map volatiles in the immediate neighborhood.
These observations will test the connection of
volatile changes to plume eruptions.
Tuesday, Nov. 17 (DOY 321)
An encounter strategy meeting was held today to
cover the period between Nov. 21 and Dec. 12,
Enceladus flyby E8 and Titan flyby T63, and
maneuvers 224 - 226. Navigation has determined
that maneuver #224 is a good candidate for early
uplink. After examining the schedule, it appears
that there are two DSN passes early Saturday
morning after the main engine cover is reopened that would work.
Visit the JPL Cassini home page for more
information about the Cassini Project:
http://saturn.jpl.nasa.gov/
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