Cassini Significant Events 09/26/07 - 10/02/07

October 5, 2007

(Source: Cassini Project)

The most recent spacecraft telemetry was acquired on Monday, Oct. 1, from the Madrid tracking complex. 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, Sept. 26 (DOY 269):

The uplink and loading of CDS version 10 fight software (FSW) to the SSRs was completed today. FSW checkout begins on Oct. 7.

DSS-63 was taken off-line unexpectedly at DOY 269/1105 UTC for contamination of the servo heater system. A scenario was selected for dealing with losses of DSS stations on DOY 270, 274, and 276. A replacement station was not available on DOY-270. All data for that day was lost. A 34m station, DSS-54 was available on DOY-276 and was arrayed with DSS-55 to support the Titan playback. Real-time commands to cut data and remove the Titan dual playback, and command the Composite Infrared Spectrometer (CIRS) to capture the highest value science for the instrument during T36 were uplinked on Friday, Sept. 28.

Thursday, Sept. 27 (DOY 270.):

DAWN launched successfully today at 4:30 a.m. Pacific Time. Cassini extends heartfelt congratulations to the DAWN flight team on this much-anticipated event.

Friday, Sept. 28 (DOY 271):

Orbit Trim Maneuver (OTM) #130 was performed today. This is the approach maneuver setting up for the Titan 36 encounter on Oct. 1. The reaction control subsystem burn began at 11:59 AM PDT. Telemetry immediately after the maneuver showed the burn duration was 14.375 seconds, giving a delta-V of 0.024 m/s. All subsystems reported nominal performance after the maneuver.

Saturday, Sept. 29 (DOY 272)

Non-targeted flybys occurred today of Dione, Enceladus, and Telesto with multiple observations by the science instruments.

Imaging Science (ISS) observed Enceladus obtaining high-resolution images of plumes, viewed perpendicular to the "tiger striped" features on the satellite. This is part of the plume search, which hopes to detect and/or observe plumes, and help in the determination of their origin. RADAR observations were also taken of Enceladus along with scatterometry & radiometry measurements for characterization of radiometric properties.

Dione was the target of Global mapping and color observations, unique RADAR observations, and additional scatterometry & radiometry measurements.

CIRS, and the Visual and Infrared Mapping Spectrometer (VIMS) also observed Dione compositional variability in wispy terrain near Amata crater. This is the last scheduled Dione observation of the prime mission.

Observations of the icy satellites continued with Tethys color photometry / polarization, and Iapetus limb topography and geodesy. Finally, instruments observed the transit of Mimas across Epimetheus, and Tethys across Calypso.

Monday, Oct. 1 (DOY 274)

Titan 36 closest approach occurred at approximately 2007-275T04:43 SCET, at an altitude of 975 km, -60 degrees latitude. This was the second flyby in the southern hemisphere of Titan. T7, performed Sept. 7, 2005 at 1075 km, was the first. T36 was 100 km lower than T7 and will serve as another data point in characterizing the atmospheric density of the southern hemisphere. The next six low altitude flybys are in the southern hemisphere, as are most of the extended mission low altitude Titan flybys.

The time at closest approach was used by the Ion and Neutral Mass Spectrometer (INMS) as part of the Magnetospheric and Plasma Science (MAPS)/TOST campaign to determine atmospheric and ionospheric composition and thermal structure. Other high-level science objectives for this flyby included RADAR Synthetic Aperture RADAR imaging of the south pole, limited global-scale mapping of the equatorial bright/dark boundary region around 1.4 N, 209 W, with an opportunity for stereo imaging with later flyby ISS. ISS also took a full-disk color mosaic of Titan at 1.4 to 1.7 km/pixel. For more information on this flyby try these links:

Titan 050TI (T36) Mission Description [PDF, 1.4 MB]

News Feature -- Titan Flyby, Oct. 2, 2007

Tuesday, Oct. 2 (DOY 275)

Last Friday the S36 Science Operations Plan Update (SOPU) process concluded and Science Planning handed off all products to Uplink Operations. Today a kickoff meeting was held for the final development process. S36 goes active on the spacecraft on Dec. 14 of this year.

The preliminary input port occurred today for the S37 SOPU. Files received from the teams participating in this sequence have been merged, and the reports sent out to the teams. The official port is scheduled for Wednesday, Oct. 10, and the process concludes on Oct. 26.