From: Jet Propulsion Laboratory
Posted: Tuesday, March 11, 2008
The most recent spacecraft telemetry was acquired on Tuesday, March 11, from the Canberra, Australia 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 located at http://saturn.jpl.nasa.gov/operations/present-position.cfm.
Wednesday, March 5 (DOY 065):
The annual Attitude and Articulation Control Subsystem (AACS) Inertial Reference Unit or "gyro" calibration was successfully completed on board the spacecraft today.
After the calibration, the Composite Infrared Spectrometer (CIRS) targeted Hyperion as part of a deep space calibration effort before undertaking a stray light calibration exercise. After the calibration, CIRS performed an 11-hour far-infrared mapping of Saturn in the north to south direction before turning to Earth for the downlink.
Today Cassini participated in a joint Emergency Command Center (ECC) exercise with the Spitzer Project at the Goldstone Deep Space Communication Complex. The purpose of the exercise was to verify the ability of that complex to support commanding to multiple spacecraft in the event of an emergency. These exercises are held on a periodic basis to confirm that the capability is still functional.
A new interactive flash about Enceladus joins the previous Titan flash on the Cassini web site. Go to the following link and click on Enceladus Virtual Tour in the upper right corner. http://saturn.jpl.nasa.gov/science/moons/moonDetails.cfm?pageID=5
Thursday, March 6 (DOY 066):
Cassini has found evidence of material orbiting Rhea, Saturn's second largest moon. This is the first time rings may have been found around a moon. A broad debris disk and at least one ring appear to have been detected by a suite of six instruments specifically designed to study the atmospheres and particles around Saturn and its moons. For the full release link to: http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=820
Commands to support a dual playback strategy for science data acquired during the Enceladus flyby on DOY-072 were uplinked today.
Friday, March 7 (DOY 067):
Orbit Trim Maneuver (OTM) #147 was performed today. This is the apoapsis maneuver setting up for the Enceladus 3 encounter on Mar. 12. The main engine burn began at 12:30 AM PST. Telemetry immediately after the maneuver showed the burn duration was 6.80 seconds, giving a delta-V of 1.11 m/ s, as planned. All subsystems reported nominal performance after the maneuver.
Saturday, March 8 (DOY-068)
Real time commands were sent to the spacecraft today in support of science observations during the Enceladus flyby. The Cosmic Dust Analyzer (CDA) switched to version 12 instrument flight software, and in order for RADAR to perform its scatterometry observations, two trigger commands based on the most recent orbit determination information were uplinked.
Monday, March 10 (DOY 070):
A non-targeted flyby of Titan occurred today.
At the final Navigation Review meeting today, the data was reviewed and it was determined that excellent accuracy had been achieved with OTM-147. We are on target. OTM-148, scheduled as the final targeting maneuver on approach to Enceladus, was therefore cancelled and replaced by a reaction wheel bias real-time command. Science Planning verified that science observations would not be impacted by the cancellation. Cancellation also eliminates a perturbation to the trajectory, which will improve the OD input to the OTM-149 design and reconstruction of the E3 flyby.
Tuesday, March 11 (DOY 071):
JPL Media Relations has coordinated an active blog covering the Enceladus 3 flyby. This flyby, under RWA control at 50 km altitude, will occur March 12. This is the closest flyby by Cassini of any body to date, and also the deepest penetration of the Enceladus plume to date. The blog allows the general public to post comments and follow along as the flyby unfolds. For access link to:
For additional links before the flyby tomorrow try the following:
An Enceladus flyby page: http://saturn.jpl.nasa.gov/news/events/titan20080312/index.cfm
And any of the links of the home page: http://saturn.jpl.nasa.gov/home/index.cfm
The main engine cover will be closed today after the scheduled OTM-148 backup pass for dust hazard avoidance right before the Enceladus 3 flyby. It will be reopened Mar. 13 before the OTM-149 prime pass.
The second delivery port for the S42 Science Operations Plan process occurred today.
Check out the Cassini web site at http://saturn.jpl.nasa.gov for the latest press releases and images.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space 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.
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