News | November 12, 2008
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: http://saturn.jpl.nasa.gov/operations/present-position.cfm.
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: http://antwrp.gsfc.nasa.gov/apod/ap081105.html
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 winners.
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.