Cassini Significant Events 10/05/06 - 10/11/06

October 13, 2006

(Source: Cassini Project)


The most recent spacecraft telemetry was acquired Wednesday, Oct. 11,
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 .

Thursday, Oct. 5 (DOY 278):

An Integrated Test Laboratory (ITL) test for the Titan 20 flyby sequence was
completed today. The test was designed to validate a sequence to obtain
accelerometer data during the T20 flyby. A modification to the telemetry
schedule was needed to collect the data every 8 seconds. T20 will occur
during the execution of S25.

A new image of Saturn demonstrates a technique that creates a 'Chinese
lantern' effect, showing Saturn's deep clouds silhouetted against the
planet's warm, glowing interior. Seen this way, Saturn's interior shows
surprising activity underneath the overlying haze, with a great variety of
cloud shapes and sizes. For more information go to http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=694

A slide show featuring colorful images of Saturn and Titan is available at
http://www.jpl.nasa.gov/multimedia/slideshows/cassini-200609/

Friday, Oct. 6 (DOY 279):

Orbit Trim Maneuver (OTM) #76 was performed on Friday, Oct. 6. This is
the approach maneuver setting up for the Titan 19 encounter on Oct. 9.
The reaction control subsystem burn began at 10:45 AM PDT. The playback data
showed the burn duration was 26.5 seconds, imparting a delta-V of
approximately 35.9 mm/s. All subsystems reported nominal performance after
the maneuver.

Monday, Oct. 9 (DOY 282):

On Oct. 9, Cassini flew by Titan at 980km above the surface at a latitude
of 61 degrees. Closest approach occurred near 2006-282T17:30:06. The RADAR
instrument performed extensive high-resolution synthetic aperture radar
imaging of the northern region where methane lakes were previously
discovered. All the data from this flyby has been received on the ground and
analysis has begun. Thruster duty cycle firing for the event was at 27.5 percent.

Tuesday, Oct. 10 (DOY 283):

The main engine (ME) cover was closed today for dust hazard avoidance on
Oct. 12. The cover will be reopened prior to the execution of OTM-77.
This is the 31st time the cover has been cycled since launch. The next
planned closing will occur in June of 2007.

Wednesday, Oct. 11 (DOY 284):

The S27 Science Operations Plan Update Project Briefing and waiver approval
meeting was held today. The final development process will begin on Monday,
Oct. 16.

Routine files to clear the CDS table entry and perform a memory read-out
were uplinked to the spacecraft today following the Solid State Power Switch
(SSPS) trip on Oct. 3. This was the last activity related to the
unexpected state change of the SSPS for the Stellar Reference Unit-A
decontamination heater.

Program Management made the decision today to cancel OTM-77. If executed,
OTM-77 would have a magnitude of 0.16 m/s. Cancellation increases the
magnitude of OTM-78 from about 0.25 m/s to about 0.85 m/s and changes it
from a reaction control subsystem to a main engine maneuver. The overall
cost of OTM-77 cancellation is about 0.47 m/s. Given this modest delta V
increase and the reduction in both risk to the spacecraft and off-shift
work, the decision was easy to come to.

Media Relations supported several Cassini press briefings at the Division of
Planetary Sciences (DPS) of the American Astronomical Society meeting this
week in Pasadena, California. One news release and two image advisories were
released in conjunction with this meeting.

At the "Saturn" briefing today at the DPS the news was "Cassini Image Shows
Saturn Draped in a String of Pearls
http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=696

At the "Rings" briefing that same day:
Saturn's Rings Show Evidence of a Modern-day Collision
http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=697

and NASA Finds Saturn's Moons May Be Creating New Rings
http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=698

In conjunction with the Titan briefing on Thursday, Oct. 12, it is
expected that two new RADAR images will be released on the web site. We will
have the links for you in the Significant Events report next week.