Status Report

NASA Cassini Significant Events for 09/21/06 – 09/27/06

By SpaceRef Editor
September 29, 2006
Filed under , , ,
NASA Cassini Significant Events  for 09/21/06 – 09/27/06

The most recent spacecraft telemetry was acquired Wednesday, September 27, from the Goldstone tracking stations. The Cassini spacecraft is in an excellent state of health and is operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the “Present Position” web page located at .

Thursday, September 21 (DOY 264):

Legislative Affairs presented 20 JPL packets to California Assemblywoman Carol Liu’s office as they will meet and greet a contingent including several people from the Vatican in Sacramento next week. The packet included the Ring World2 DVD, Cassini’s “Jewel of the Solar System” poster, and Solar system lithographs.

Cassini also provided materials to Legislative Affairs for Congressman Calvert’s office and their annual Science and Technology Education Partnership conference. Three thousand folders were sent to support this event.

The discovery of the new ring, some amazing images including some from the Titan 17 flyby, and an image of Earth from Saturn taken by Cassini kept the web team busy posting releases and images:

  • Titan’s “Kissing Lakes”/ September 26
  • Long-lived Vortices/ September 26
  • Duotone Moon/ September 25
  • Blustery Bands/ September 22
  • Pale Blue Orb (2)/ September 19
  • Ghostly Fingers of Enceladus/ September 19
  • The Janus/Epimetheus Ring/ September 19

Outreach presented an overview of Cassini-Huygens Education and Public Outreach (EPO) to scientists and outreach specialists from throughout Europe at ‘Europlanet’ in Berlin, Germany last week. While the major focus of the conference was scientific, an entire session day was devoted to outreach and the vital role scientists play in boosting the public’s awareness and support for space science. Over 50 people attended the session, which included talks from the European journalism community, university researchers, and EPO specialists from the European Space Agency.

Friday, September 22 (DOY 265):

The Titan Orbiter Science Team hosted a Titan 19, 20, 21, and 22-flyby preview today. The goal of the meeting was to review the science objectives, measurements, and science acquisition planned for each of the flybys.

Saturday, September 23 (DOY 266):

On Saturday, September 23, Cassini flew by Titan at an altitude of 960km and a latitude of 71 degrees. Throughout the flyby, Magnetospheric and Plasma Science (MAPS) teams performed observations of Titan’s interaction with Saturn’s magnetosphere, and the Visual and Infrared Mapping Spectrometer obtained visible and infrared images at high, medium and global resolution. The closest approach time was significant as the Ion and Neutral Mass Spectrometer (INMS) was able to obtain data to help determine Titan’s atmospheric and ionospheric composition and thermal structure. RADAR also completed several minutes of Synthetic Aperture Radar coverage of Titan’s surface near closest approach. For a full description of the flyby link to: escription.pdf

Near periapsis, two days later, the Composite Infrared Spectrometer executed a radial scan of the main rings to obtain sub-millimeter wavelength measurements at a variety of geometries, and the Magnetospheric Imaging Instrument imaged certain dynamics of the inner magnetosphere. Additional ring observations were carried out by all of the Optical Remote Sensing instruments by observing a star as the rings occulted its light.

Sunday, September 24 (DOY 267):

The DOY 268 Live Inertial Vector Propagator Update of the Janus vector was uplinked to the spacecraft today at 267/16:51:40. Confirmation has been received that it is on board and registered.

Monday, September 25 (DOY 268):

A non-targeted flyby of Methone occurred today at an altitude of 63,731 km. After canceling Orbit Trim Maneuver (OTM) #73 last week, the Navigation team took a look at the impact of canceling OTM-074 as well. OTM-074 currently has a magnitude of 0.33 m/s, and is the T18 cleanup maneuver set for September 26. Since OTM-75 is a fairly large deterministic maneuver, the overall cost of canceling OTM-74 is about 0.2 m/s. It has been decided to cancel OTM-74 and roll the delta V into OTM-075.

Navigation has delivered the “no maneuver” trajectory to Science Planning, the project file repository, and the DSN. These files do not include OTM-75 and thus are only valid up to the time of OTM-75 execution on October 1. A Reaction Wheel Bias command has been approved and will be uplinked on tomorrow morning’s pass. Science Planning will now do a formal analysis to determine if a live update to adjust instrument pointing is required as a result of the OTM-74 cancellation.

The S27 preliminary port delivery occurred today in support of the Science Operations Plan Update process. The analysis of the merge has been delivered to the teams for review. The official port is scheduled for Friday, September 29.

On Monday, Sept. 25, media relations provided the post Titan 18 flyby newsnote which appears on the Cassini mission web site, NASA portal and on the JPL homepage. To view the report link to:

Tuesday, September 26 (DOY 269):

A Cassini-Huygens Analysis and Results of the Mission (CHARM) telecon was held today. The topic was “Titan: The Solar System’s Abiotic Petroleum Factory” and was presented by the team leader for the Cassini Ion and Neutral Mass Spectrometer investigation. A PDF of this and previous presentations may be downloaded by linking to:

CHARM telecons are the last Tuesday of the month from 11:00 am to 1:00 pm Pacific Time.

On Tuesday, September 26, media relations and the RADAR team issued two RADAR images from the Titan 18 flyby showing more lakes. Although this pass was primarily dedicated to the ion and neutral mass spectrometer instrument and the volume of radar data was small, scientists were amazed to see Earth-like lakes appear in radar images. The images can be viewed at the photo journal: and

Wednesday, September 27 (DOY 270):

The Titan Atmosphere Model Working Group (TAMWG) met today to discuss post T18 results. INMS, AACS, and Navigation calculated densities at the T18 flyby that were slightly below pre-flyby model estimates. In this case, the duty cycle was predicted at 49% and the actual was 42%. Duty cycling is a measurement of how often the thrusters fire in order to keep the spacecraft pointed in the correct direction in response to atmosphere-generated torques. 100% duty cycles would mean that the thrusters are firing all the time. The percentages reported after the T18 flyby indicate that the data is consistent with other nearby data points and does not indicate that there is significant risk of losing attitude for the upcoming T19 or T20 flybys. The TAMWG agreed to refine the atmosphere model and update duty cycle and density predictions for all future flybys by January 2007.

A Delivery Coordination Meeting was held today for the Imaging Science Subsystem Pre-Commanding Tool (ISSPT) version 2.6.5. ISSPT was developed by the Cassini ISS Team to adjust and optimize ISS camera settings, calculate image brightness levels and compression based on pointing, and produce Instrument Operations Interface (IOI) output files used in building camera command sequences.

An image of the rings of Saturn with Earth in the far distance is Astronomy Picture of the Day today.

Wrap up:

Check out the Cassini web site at for the latest press releases and images.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Spsce Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington, D.C. JPL designed, developed and assembled the Cassini orbiter.

SpaceRef staff editor.