NASA Cassini Significant Events 09/01/10 – 09/07/10
The most recent spacecraft telemetry was acquired on Sept. 7 from the Deep Space Network tracking complex at Canberra, Australia. 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/mission/presentposition/.
Wednesday, Sept. 1 (DOY 244)
The S63 background sequence was uplinked to the spacecraft today. The sequence is registered onboard and will begin execution on Sept. 6, running through Oct. 11.
Thursday, Sept. 2 (DOY 245)
This week Radio Science (RSS) performed a gravity science enhancement activity. The Visual and Infrared Mapping Spectrometer (VIMS) took a hemispherical map of Saturn and captured some very high phase angle observations of the rings while the Sun was eclipsed by the disk of Saturn.
The Composite Infrared Spectrometer (CIRS) examined the south (dark) side of the rings to determine how the rings responded to the change of seasons following the August 2009 equinox. Imaging Science (ISS) created color mosaics of Dione, as well as took observations of its so-called wispy streaks. ISS also imaged a mutual event where Telesto, one of the small satellites of Saturn, transited across another satellite, Rhea. ISS and CIRS completed a 17.5 hour observation of faint rings at low elevation angles and high phase angles.
Friday, Sept. 3 (DOY 246)
Orbit Trim Maneuver (OTM) #261 was performed today. This was the apoapsis maneuver setting up for the Titan 72 (T72) encounter on Sept. 24. The main engine burn began at 10:00 PM PST. Telemetry immediately after the maneuver showed a burn duration of 14.145 seconds, giving a delta-V of 2.434 m/s. All subsystems reported nominal performance after the maneuver.
The Dione Live Inertial Vector Propagator update was executed today.
Monday, Sept. 6 (DOY 249)
The S62 background sequence execution was completed today, and S63 sequence execution began.
Tuesday, Sept. 7 (DOY 250)
The DSN track today over Canberra, Australia, started with a Solid State Power Switch (SSPS) trip alarm. Upon investigation, the switch was identified as the main engine-A prime replacement heater. This is the 33rd in-flight SSPS trip, about 50 days since the previous trip in July on the switch that powers CDS Engineering Unit B. This time the switch was off at the time of the trip and was set back to off by fault protection; it is currently still off. Next week commands will be sent to reset the SSPS trip counter. Cruising past Saturn’s moon Dione this past weekend, Cassini got its best look yet at the north polar region of this small, icy moon and returned stark images of the fractured, cratered surface. For more information on this subject and for raw images, link to: http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20100907/.
