Cassini Significant Events 11/22/06 - 11/29/06

December 1, 2006

(Source: Cassini Project)


The most recent spacecraft telemetry was acquired Wednesday, Nov. 29, from the Goldstone 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 at http://saturn.jpl.nasa.gov/operations/present-position.cfm .

Wednesday, Nov. 22 (DOY 326):

The December issue of National Geographic Magazine, which is on newsstands now, features the Cassini-Huygens mission in a 20-page article.

To preview visit:

http://www7.nationalgeographic.com/ngm/0612/index.html

Also in this issue is a pullout poster of the planets, available as an
interactive feature at:

http://www7.nationalgeographic.com/ngm/0612/feature1/zoomify/index.html

Thursday, Nov. 23 (DOY 327):

JPL Holiday

Friday, Nov. 24 (DOY 328):

JPL Holiday

The S25 sequence concluded and S26 began execution today at
2006-328T16:30:00. The sequence will run for 42 days and conclude on Jan.
5, 2007. During that time there will be two targeted encounters of Titan and
three non-targeted flybys - two of Titan and one of Telesto. Seven OTMs are
scheduled, numbered 81 through 87.

Today RPWS wrapped up a 2.5-day campaign to monitor the solar wind. This
study needed to be performed while Cassini was well upstream of Saturn's bow
shock in careful coordination with Earth based observations of Saturn's
aurora.

A Science Allocation Plan (SAP) mini-sequence for the Radio and Plasma Wave
Science instrument was uplinked to the spacecraft today. The mini-sequence
will run from DOY 330-335.

Saturday, Nov. 25 (DOY 329):

A non-targeted flyby of Titan occurred today at an altitude of 925,150 km.
During this flyby, RADAR obtained distant Titan observations in preparation
for T21. The distant Titan radiometer scans provide data to help remove the
effect of spillover sidelobes in the Synthetic Aperture RADAR (SAR)
radiometry data. This greatly enhances the value of radiometry data obtained
coincident with the SAR image.

Sunday, Nov. 26 (DOY 330):

The Solid State Power Switch (SSPS) on the Reaction Wheel Assembly (RWA) #4,
line #1, unexpectedly changed state from ON to tripped at 329T18:35:06 SCET
today. There was no impact to spacecraft performance, as there are two power
lines per RWA and a single line is capable of carrying the entire load. The
tripped switch was brought back on-line by a command from the ground. This
was done using a new on-the-shelf "Tripped RWA SSPS" procedure developed
after the last such trip on Nov. 3, 2005. The spacecraft is operating
normally following this activity.

These SSPS trips have been seen before and are most likely caused by
Galactic Cosmic Rays. So far there have been 20 such trips since launch, and
they are predicted to occur at a rate of about two per year. This is the
first time an SSPS tripped that had tripped in the past. The SSPS for RWA-4
line 1 previously tripped on Nov. 3, 2005. Interestingly, the last five
trips, since May 1, 2006, have occurred about 7-8 weeks apart.

Monday, Nov. 27 (DOY 331):

Orbit Trim Maneuver (OTM) #81, an apoapsis maneuver, was performed today.
This was the first time in the mission where an OTM executed over the backup
opportunity was significantly smaller than it would have been if executed
during the prime opportunity. The difference was 0.2 m/sec vs. 0.75 m/sec.
The reaction control subsystem burn began at 6:29 AM PST. Telemetry
immediately after the maneuver showed a burn duration of 160.1 seconds,
giving a delta-V of 0.22 m/s. All subsystems reported nominal performance
after the maneuver.

A beautiful image of the spokes in the rings of Saturn is Astronomy Picture
of the Day today.

Tuesday, Nov. 28 (DOY 332):

Today the Imaging Science Subsystem and the Ultraviolet Imaging Spectrograph
performed a synergistic radial scan following the shadow boundary on the
main Rings. Performing this type of observation at this specific geometry
will help identify inclined rings.

The S28 kick-off meeting was held today as part of the final sequence
development process. The flight team has been considering for some time how
to streamline the overall development process consisting of the Aftermarket
Process, Science Operations Plan Update Process (SOPU), and the final piece,
the Science and Sequence Update Process (SSUP). As a result, the SOPU final
meeting and presentation to Program Management has been combined with the
SSUP kick-off meeting. The combining of these two meetings has proved to be
a significant time saver for members of Science Planning and Uplink
Operations.

At the Mission Planning Forum today, DSN personnel presented the results of
a study, performed at the request of Mission Planning, to determine possible
DSN resource conflicts - due to competition with other missions and antenna
down times - during extended mission. This was followed by a discussion on
how best to plan around the conflicts.

The Cassini-Huygens Analysis and Results of the Mission (CHARM)
teleconference for November was held today. The topic addressed a new
perspective on the rings of Saturn as well as recent results on the faint
rings.

A member of the Cassini Mission Support & Services Office (MSSO) gave a
presentation on Cassini to 60 students from three third grade classes at
Mayfield Junior School in Pasadena, CA today. The students and teachers
received outreach material and created Saturn books using Cassini's K-4
literacy program, Reading, Writing and Rings. Lesson 9, "Focus on Saturn's
Fascinating Features", is a great activity for informal as well as formal
education audiences. Here is a link to some of the program activities: http://saturn.jpl.nasa.gov/education/edu-k4-12b.cfm





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