Cassini Significant Events 03/07/07 - 03/13/07

March 15, 2007

(Source: Cassini Project)

The most recent spacecraft telemetry was acquired on Tuesday, March 13, from the Goldstone 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" web page at .

Wednesday, March 7 (DOY 066):

On Monday, March 5, the sequence leads hosted a meeting to discuss Radio and Plasma Wave Science (RPWS) whistler observations in future sequences during the remainder of prime mission. There are only nine possible opportunities remaining for this activity. At Monday's meeting the details for S29 and S30 were specifically addressed.

Thursday, March 8 (DOY 067):

DSN representatives were able to release a DSN allocation file for the S28 background sequence on March 5. S28 has been executing since Feb. 17 but the sequence leads were able to take advantage of this opportunity to acquire more science data. Science Allocation Plan (SAP) discussions were held regarding the distribution of real-time sponge bits as well as the upgrade of DOY-073 DSS-15, a hef, to DSS-14, the 70-meter antenna at Goldstone that would allow faster data transmission. A real-time SAP mini-sequence was uplinked to the spacecraft today. It has registered on board, will begin execution on March 13, and will run for the remainder of the sequence concluding on March 27.

Periodically this weekly report mentions the activities of the sequence leads for Cassini. Meet one of them in the most recent video mission report released by the media relations team. The video is available at:

Saturday, March 10 (DOY 069):

The Titan 26 targeted flyby occurred today at an altitude of 980 km. Spacecraft Operations reported that the thruster duty cycle was about 36%, and 446.8 g of hydrazine were used, very close to the predicted amount of 430 g. Observations for this flyby included Imaging Science Subsystem observations of the south pole and performing full-disk color imaging. The Composite Infrared Spectrometer performed stratospheric and tropospheric mapping of composition and temperature, in addition to limb sounding of the stratosphere for vertical resolution and a surface temperature scan. The Ultraviolet Imaging Spectrograph measured dayside and night side emissions in addition to performing a solar occultation, and the Visual and Infrared Mapping Spectrometer monitored cloud motion on Titan, probing the deep structure of Titan's atmosphere during the solar occultation, and mapping of mid-latitude regions at moderate solar phase angles.

Monday, March 12 (DOY 071):

The S28 DOY 076-083 Live Inertial Vector Propagator Update kickoff meeting was held today. Under consideration was an update for Saturn observations with the Optical Remote Sensing instruments driving the request. After Navigation provided the orbit determination solution for OTM-098, it was determined that the maximum possible pointing error was 0.675 mrad. With that small an error the team was able to cancel the update.

A news release went out today discussing the geysers on Enceladus. The challenge for researchers has been to figure out how this small ice ball could produce the levels of heat needed to fuel such eruptions. A new model suggests the rapid decay of radioactive elements within Enceladus shortly after it formed may have jump-started the long-term heating of the moon's interior that continues today. The model provides support for another recent related finding, which indicates that Enceladus' icy plumes contain molecules that require elevated temperatures to form. To gather more information about the chemistry within Enceladus, the instruments on Cassini will directly measure the gas emanating from the plume during a flyby scheduled for March 2008. For more on this development link to:

Tuesday, March 13 (DOY 072):

Orbit Trim Maneuver (OTM) #98 was performed today. This is the cleanup maneuver for the Titan 26 encounter on March 10. The main engine burn began at 12:15 AM PST. Telemetry immediately after the maneuver showed the burn duration was 6.64 seconds, giving a delta-V of 1.07 m/sec. OTM-098 was the first use of Maneuver Automation Software version 6.1.1. All subsystems reported nominal performance after the maneuver.

In addition to the Enceladus report, another news release went out on the latest Titan Seas story. Instruments on board Cassini have found evidence of huge seas on Titan. Scientists reported the seas were likely filled with liquid methane or ethane and that the discovery reinforced previous theories. Because of this new information, the flight team is changing the pointing of the radar instrument during a May fly-by so it can scan directly over the dark areas seen by the cameras. For more information link to