Cassini Significant Events
06/28/08 - 07/08/08
The most recent spacecraft telemetry was acquired on July 8 from the
DSN tracking complex at Goldstone, California. 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/operations/present-position.cfm.
Saturday, June 28 (Day of Year (DOY) 180):
A non-targeted flyby of Titan occurred on June 28. In addition,
non-targeted flybys of Prometheus, Enceladus, Janus, Methone and
Atlas will occur on June 30, and of Janus, Pandora and Methone on
July 7.
Monday, June 30 (DOY 182):
Another important milestone occurred today in the implementation of
the Cassini extended mission. The final integrated S47 sequence
segments, which include orbits 99 through 103, were delivered today.
S47 executes from Jan. 9 to Feb. 17, 2009. Between now and then, the
Science Operations Plan process and Science and Sequence Update
process must be completed in order to create a sequence that then can
be approved and flown on the spacecraft. As of today, scientists
will begin working on their pointing designs. The final Cassini Deep
Space Network (DSN) station requests for January and February will be
delivered to the DSN schedulers on July 7.
All participating teams have given their go-ahead for the DOY 188
Live Inertial Vector Propagator (IVP) update and DOY 189 Radio
Science (RSS) Live Movable Block update. Uplink Operations will now
build the files that will be sent to the spacecraft on July 2.
The final science of the prime mission included an RSS Gravity
Science experiment, a Radio and Plasma Wave Science (RPWS) auroral
crossing observation, and instrument observations of the rings,
Mimas, Enceladus, Janus and Tethys.
Tuesday, July 1 (DOY 183):
Today is a big day in the life of the Cassini Program. It is the 4th
anniversary of the July 1, 2004 Saturn Orbit Insertion, the end of
the Prime Mission, the start of the Cassini Equinox Mission and the
start of execution of the first extended mission sequence, S42.
The S41 sequence concluded and S42 began execution today at
2008-83T19:08 SCET. The sequence will run for 40 days, concluding
Aug. 11. During that time, there will be one targeted encounter of
Titan and 16 non-targeted flybys -- two each of Daphnis, Prometheus,
Pallene, Pan, and Epimetheus, and one each of Titan, Atlas, Mimas,
Janus, Pandora and Methone. Three Orbit Trim Maneuvers (OTM) are
scheduled, numbered 160, 162 and 163.
Just as Cassini is about to launch a new phase of its tour of Saturn,
the interactive Cassini at Saturn Interactive Explorer (CASSIE) has
gotten a significant upgrade. Version 2 makes it easier to navigate
through time and view significant mission events. There are now
cameras "stationed" near seven of Saturn's moons so the viewer can
watch events from a different perspective. An artificial, dual-power
"Laser Range Finder" has been added to measure distances between
Cassini and its targets and to allow the user to temporarily "leave
your mark" on Saturn's moons. CASSIE makes real Cassini mission data
fully available in three colorful, easy-to-use expeditions. The new
tool is online at: http://saturn.jpl.nasa.gov/multimedia/CASSIE/
Wednesday, July 2 (DOY 184):
The first update files for S42 were uplinked to the spacecraft today.
These include a DOY 188-190 Saturn/Enceladus Live Inertial Vector
Propagator Update sequence that will begin execution on Sunday, and
DOY 189 RSS Saturn occultation LMB that will execute on Monday.
Science observations for S42 occur during orbits 74 thru 80 at a
high-inclination angle. This geometry will allow Imaging Science
(ISS) to obtain full coverage of ringlets and gaps in the C- and
D-rings, which is not possible in lower-inclination orbits.
Highlights this week include an ISS spoke movie on DOY 184, a Visual
and Infrared Mapping Spectrometer (VIMS) F-ring movie on DOY 187, and
three star occultations on DOY 188, 190 and 191.
During the Cassini Equinox Mission, a great deal of Rings Target
Working Team attention will be focused on the F-Ring, studying its
transient structures and looking for the bodies that create
near-constant disruptions of those structures. The Rings group will
be using several bright infrared and ultraviolet stars to probe the
densest portions of the ring system, the Composite Infrared
Spectrometer (CIRS) will continue with thermal studies, and VIMS will
continue with studies of ring composition.
Monday, July 7 (DOY 189):
The Science Operations Plan process for S44 completed today.
Tomorrow, Science Planning and Uplink Operations will hold the
hand-off meeting that begins the final development process for this
sequence. S44 will begin execution on Sept. 13.
Tuesday, July 8 (DOY 190):
On July 8, Uplink Operations began sending a number of files to the
spacecraft in support of a new Flight Software (FSW) update for the
Cosmic Dust Analyzer (CDA). The update is desired for the
Enceladus-4 targeted encounter on Aug. 11. Instrument FSW version
12.2 was sent to the spacecraft today. Over the next three days,
additional files will be sent for a flight software checkout
activity, and the first of two FSW demonstrations, this one for a
ring-plane crossing. The instrument checkout will execute on July 11.
The Live Update train just keeps steaming along. Since both the
Saturn/Janus/Rhea/Mimas update on DOY 196, and the Saturn/Dione
update on DOY 203 use the orbit determination solution being released
today, the sequence leads have combined the two activities into one
process. The kick-off meeting occurred today and the Go/No-Go
meeting is scheduled for tomorrow for input from CIRS, ISS, VIMS,
Spacecraft Operations, Science Planning and Navigation.
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