NASA Cassini Significant Events for 09/24/08 – 09/30/08

The most recent spacecraft telemetry was acquired on Sept. 30 from the Deep Space Network tracking complex at Madrid, Spain. 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, Sept. 24 (DOY 268):

The Optical Remote Sensing (ORS) instrument teams and the Science Planning team have all confirmed that live update #3 for Saturn and Tethys on DOY 275-277 is not required and may be cancelled.

An AACS friction test of the backup reaction wheel (RWA) #3 was completed Sept. 23. For this test, performed every six months, the RWA is spun up to 600 rpm in both the clockwise and counterclockwise directions and timed as it is allowed to run down to zero. Results, compared with the previous friction test performed on this wheel on Apr. 6, showed no significant changes.

An encounter strategy meeting was held today to review the period between Oct. 9 and Nov. 3, the Enceladus 5 and 6 flybys, Titan 46, and maneuvers 167-169.

Science activities today began with VIMS observing the bright star Gamma Crucis as it was occulted by the rings. This was followed by a downlink to Madrid, then VIMS scanning the unlit side of the rings, and UVIS observing a stellar-ring occultation. The day finished with a unique observation of Tethys as it passed through Saturn eclipse. All ORS instruments took data, with CIRS having prime pointing control to observe the thermal response of Tethys as it passed into Saturn’s shadow.

Thursday, Sept. 25 (DOY 269):

Non-targeted flybys of Tethys, Atlas, Pan, and Pallene occurred today.

Today began with the spacecraft passing through periapsis, the point where the spacecraft is closest to Saturn for this orbit. During periapsis, Magnetospheric and Plasma Science (MAPS) instruments collected data at increased rates to observe the auroral magnetosphere and Saturn Kilometric Radiation source region. Later, when the spacecraft turned to Earth to play back data to Goldstone, Radio Science transmitted Ka-band frequency data to characterize the Saturn gravity field.

Friday, Sept. 26 (DOY 270):

Heading away from periapsis, Friday began with a small satellite orbit determination activity. Then the ORS instruments used a relatively close Rhea encounter to acquire moderate resolution imaging data for geologic mapping. During the middle part of the day the spacecraft transmitted data back to Earth, and for the last part of the day ISS took data for an approximately10 hour ring movie to search for possible spokes and periodicities.

Monday, Sept. 29 (DOY 273):

Cassini Outreach, the JPL Education Office, the Laboratory for Atmospheric and Space Physics, and Cassini mission engineers and scientists will be participating in an educator workshop from Sept. 29 through Oct. 6 in Tennessee. The purpose of the workshop is to test the next iteration of language arts “Through the Eyes of a Scientist” with educators, the Eastern Tennessee State University Center for Excellence in Mathematics and Science Education, and the International Storytelling Center.

All sequence participants delivered Port 3 files as part of the S47 Science Operations Plan Implementation process. A merge of all submitted files has been performed, and Science Planning analysis of the merge will be available Sept. 30.

Tuesday, Sept. 30 (DOY 274):

Over the weekend the ORS instruments performed a coordinated observation of the icy moon Mimas, taking data for longitudinal and phase coverage, and spectroscopy data to measure composition. Today the spacecraft is operating quietly out near apoapsis beginning with a 9-hour downlink to Madrid after which ISS performed a small satellite orbital determination activity. The cameras then turned towards Titan to continue the cloud monitoring campaign. The day’s activities finished with an approximately 12 hour medium resolution F ring movie.

Visit the JPL Cassini home page for more information about the Cassini Project: http://saturn.jpl.nasa.gov/