Cassini Significant Events 01/04/07 - 01/10/07

January 12, 2007

(Source: Cassini Project)

The most recent spacecraft telemetry was acquired on Wednesday, Jan. 10, 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

Thursday, Jan. 4 (DOY 004):

The Saturn Observation Campaign coordinator provided the following information this week:

The planet Saturn is once again visible in the early evening for sky watchers everywhere. Saturn viewing tips for 2007 can be found at: 

Additional outreach resources such as presentations, posters, activities, video, podcasts, sounds, images and news from Cassini are available on this one-stop resource page:

Friday, Jan. 5 (DOY 005):

Orbit Trim Maneuver (OTM) #87 was performed today. This is the apoapsis maneuver setting up for the Titan 23 encounter on Jan. 13. The main engine burn began at 3:59 AM PST. Telemetry immediately after the maneuver showed the burn duration was 10.2 seconds, giving a delta-V of 1.63 m/s. All subsystems reported nominal performance after the maneuver.

A new background sequence, S27, began execution on board the spacecraft today. The sequence will run for 43 days, concluding on Feb. 17. During that time there will be two targeted and two non-targeted encounters of Titan, and six maneuvers numbers 88 through 93. Although the sequence is approved and currently running, there are still a few items to wrap up. Negotiations have now been completed for DSN coverage. There don't appear to be any impacts to Cassini. A real-time Science Allocation Plan meeting will be scheduled to give away bits for DOY021 and beyond. Real time commands are still to be built for the Titan 23 and Titan 24 dual playback for closest approach data for VIMS and RADAR. These were unable to be accommodated in the background sequence due to the delay in obtaining the allocation file. Real-time commands will also be built for a proposed Cosmic Dust Analyzer (CDA) flight software test, and for Ion and Neutral Mass Spectrometer (INMS) flight software normalization.

When S27 execution began at 2007-005T13:50, Cassini was at a distance of 1,703,530 km from Saturn, providing a panoramic view that enabled the Imaging Science Subsystem (ISS), Visual and Infrared Mapping Spectrometer (VIMS), and Ultraviolet Imaging Spectrograph (UVIS) to make a movie of the F-ring.

A Delivery Coordination Meeting (DCM) was held today for version 2.1 of the Spacecraft Operations Office tool CK-Compare. The C-Kernel Comparison Tool (CK-Compare) is an application consisting of two processes. In the first process, the software compares two C-Kernels and generates a comparison file and a summary report. The comparison file is then sent through the Gallery Plot tool to graphically depict the C-Kernel comparisons.

Saturday, Jan. 6 (DOY 006):

All of the optical remote sensing instruments participated in a spoke tracking campaign to follow spokes around the ring at the Keplerian rate for several hours, then move back to the starting position and follow the ring motion again. The evolution of the shape of the spokes will help Cassini scientists to formulate an explanation for their origin.

The Magnetospheric and Plasma Science instruments are conducting an ongoing magnetospheric survey to measure the magnetic field and establish its variability over space in the Saturnian system as well as over time. In addition, CDA continues obtaining data for the dust survey.

Tuesday, Jan. 9 (DOY 009):

UVIS observed an occultation of the double star Gamma Gru by the A-ring today. Gamma Gru, which is 230 light years distant from Earth, is a blue-white star of spectral type B8. Scientists can glean information on ring structure and dynamics from the high-resolution profile of optical depth measured during the occultation. The Magnetometer Subsystem (MAG) performed a calibration, rolling the spacecraft about an axis to determine sensor offsets.

Wednesday, Jan. 10 (DOY 010):

Orbit Trim Maneuver (OTM) # 88 was performed today. This was the approach maneuver setting up for the Titan 23 encounter on Jan. 13. The reaction control subsystem burn began at 3:29 AM PST. Telemetry immediately after the maneuver showed a burn duration of 27.9 seconds, giving a delta-V of 41 mm/s. All subsystems reported nominal performance after the maneuver.

A dry run was held earlier this week of the procedures for upload of AACS version A.8.7.5 flight software. Today at the Uplink Readiness Review, the software was approved for uplink with only a minor modification recommended to the procedures regarding the uplink backup pass. The software is scheduled to go up to the spacecraft in late January and early February.

UVIS mapped the volatiles N2, CO2, and CH4 in the immediate vicinity of Enceladus today to test the connection of changes in these chemicals to plume eruptions. This is an on-going activity with seven similar observations made in the last quarter of 2006. Titan at 120º phase was the subject of ISS and CIRS photopolarimetry.

The S30 Science Operations Plan update process kick-off meeting was held today. Following that was a Science Allocation Plan meeting for S27. Now that S27 has received the final allocation file from DSN representatives, Cassini Science Planning was able to take a look at the DSN coverage and determine if there were any extra bits that could be given to the science teams. A proposed bit allocation plan was distributed prior to and finalized at the meeting.