Cassini Significant Events
11/05/08 - 11/11/08
The most recent spacecraft telemetry was acquired on Nov. 11 from the
Deep Space Network 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:
Wednesday, Nov. 5 (DOY 310):
A close-up picture of Enceladus from 1,700 km above the surface is
Astronomy Picture of the Day today. It may be seen at:
This year's Cassini Scientist for a Day contest has received more
than twice the number of essays as in previous contests. Twenty-eight
judges from the Cassini flight team are now reviewing 434 essays
submitted by 615 students, from 70 teachers, representing 31 states.
The 434 essays will be narrowed down to approximately 80 from which
Project mission planning and science personnel will select the
Thursday, Nov. 6 (DOY 311):
Cassini Outreach and the JPL Education office led a professional
development workshop about "Reading, Writing & Rings" for teachers at
the California Science Teachers Association (CSTA) annual conference
on Nov. 1. When the California State University system and the CSTA
board unveiled the new online resource catalog MERLOT (Multimedia
Educational Resource for Learning and Online Teaching), Cassini's
RWR materials were prominently displayed as one of MERLOT's
outstanding products for teachers to use. The CSU-MERLOT partnership
focuses on California K-12 science teachers and CSU faculty,
providing access to high quality, peer reviewed teachable lessons and
related online resources made available at www.merlot.org.
Friday, Nov. 7 (DOY 312):
Today Imaging Science (ISS) took a complete high-resolution
longitudinal scan of the F-ring from the unlit side, followed by the
Ultraviolet Imaging Spectrograph (UVIS) observing a pair of stellar
occultations by the rings. The Visual and Infrared Mapping
Spectrometer (VIMS) then performed a scan of the rings from the unlit
side, mostly in the region of Saturn's shadow, and the Composite
Infrared Spectrometer (CIRS) performed ring thermal mapping.
Saturday, Nov. 8 (DOY 313):
Non-targeted flybys of Polydeuces, Telesto, and Enceladus occurred today.
Orbit Trim Maneuver (OTM) #170 was performed today. This is the
cleanup maneuver from the Enceladus 6 and Titan 46 encounters on Oct.
31 and Nov. 3. The main engine burn began at 3:44 PM PST. Telemetry
immediately after the maneuver showed the burn duration was 54.6
seconds, giving a delta-V of 9.09 m/s. All subsystems reported
nominal performance after the maneuver.
During the execution of OTM-170, the Radio and Plasma Wave Science
(RPWS) instrument performed another observation in the search for
lightning whistlers. For the rest of Saturday and Sunday, the
Cassini Plasma Spectrometer (CAPS) performed observations of the
auroral field lines and the Saturn Kilometric Radiation source
region, ISS scanned the Maxwell ringlet region in search of small
moons and looked at small rocky moons to obtain more data on orbit
determination, VIMS observed a stellar occultation in the B-ring, and
all the Optical Remote Sensing (ORS) instruments observed Titan as
part of an ongoing cloud monitoring campaign.
Monday, Nov. 10 (DOY 315):
Science Planning hosted a kick-off meeting today for the S50 Science
Operations Plan process. Development for this sequence will continue
until May 2009 when it goes active on-board the spacecraft.
Instrument Expanded Block (IEB) files are sent up to the spacecraft
prior to the start of each new background sequence. One of the
ongoing concerns for Spacecraft Operations (SCO) in the uplink of
these files has been the possibility of an SSR swap occurring while
the uplink is in progress, which would cause a file corruption in SSR
memory. Until now the way around this issue has been to either
perform careful calculations in selecting an uplink time in order to
predict and avoid this occurrence, or recover the file after the fact
if a swap occurred. To address this, CDS team members have created a
file of commands to be sent at the end of every IEB uplink pass. This
file enables an autonomous repair of the SSR memory with no impact on
science data collection and playback, and significantly reduces the
effort necessary to get these files on-board the spacecraft. The file
was successfully tested today and is ready for operational use.
Tuesday, Nov. 11 (DOY 316):
Teams submitted their Port 2 modified spacecraft activity sequence
files as part of the Science Operations Plan process for S49.
At the Mission Planning Forum today, members of the Spacecraft
Operations Office gave a presentation on power management for the
post extended mission time frame. Example operational modes were
presented using current instrument power allocations. Times of
future power shortages were identified where the Radioisotope
Thermoelectric Generator heat production decay with time will result
in insufficient power being available to support all of these modes.
Proposals were presented to mitigate the shortfall as needed.
Saturn has its own unique brand of aurora that lights up the polar
cap, unlike any other known planetary aurora in our solar system.
It's not just a ring of auroras like those seen at Jupiter and Earth,
this aurora covers an enormous area across the pole. For more on
this release link to:
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