Cassini Significant Events for 09/08/05 - 09/14/05 The most recent spacecraft telemetry was acquired Tuesday, September 14, from the Madrid 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 http://saturn.jpl.nasa.gov/operations/present-position.cfm . Thursday, September 8 (DOY 251): All teams and offices supported the Cassini Monthly Management Review. Friday, September 9 (DOY 252): A meeting was held today to determine if Orbit Trim Maneuver (OTM) #32 could be cancelled. It turned out that this maneuver would provide a maximum pointing improvement of only ~8 microradians, or, according to a member of the Spacecraft Operations Office, "It's teeny." Science representatives at the meeting agreed. Other factors discussed included some additional delta-V farther along in the tour if the OTM was cancelled, around 200 to 250 mm/s, and the fact that navigation accuracy requirements are met without doing the maneuver. With this information, the Project decided not to perform the maneuver. A Delivery Coordination Meeting for Ck-compare Version 2 was held today. The biggest change in the software involves allowing comparisons of C-Kernels produced by a number of different tools. Another new feature is the capability to turn on or off the Autoscaling feature of Gallery Plot. All proposed science and engineering changes were submitted today as part of the Aftermarket process for S19. The process will kick-off next Wednesday with a meeting to assess the list of changes. Saturday, September 10 (DOY 253): A Reaction Wheel Assembly bias command was uplinked to the spacecraft today. This commanding was necessary as a result of the cancellation of OTM-32, which otherwise would have included the biasing as part of the maneuver sequence. A three-day procedure to perform a fuel-side re-pressurization on board the spacecraft began today. This is the first of two fuel-side re-pressurizations planned for the tour. One was performed previously during the Cruise phase between Trajectory Correction Maneuvers 9 and 10. The timing of the re-pressurization optimizes the mixture ratio for maximum mission delta-V. A Cassini Image of Jupiter was Astronomy Picture of the Day (APOD) today. This is an encore of an image that was first APOD in July of 2000. Our outreach folks did some research and it turns out that Cassini images have been selected for encores five times. Monday, September 12 (DOY 255): The S17 SOP Update preliminary port occurred today. The products were merged and the reports published for review. Official port is scheduled for Friday, September 16. The S18 Aftermarket process concluded today with the Target Working Teams and Orbiter Science Teams completing their re-work of the sequence. S18 is now being prepared for SOP Update, which will kickoff Monday, September 26. Tuesday, September 13 (DOY 256): A significant amount of science data was lost during the recent Titan flyby as a result of an operational problem at the DSN tracking station, and a software error on the spacecraft. The software error was the larger contributor of the two causes, and the data loss resulted from an improperly set flag preventing the spacecraft from writing to or reading from the A side of the solid state recorder, so the result was performing the encounter with only half of the expected data storage volume. Commands will be sent on September 15 to reset the flag to its proper value, and normal operation is expected after this. The nature of the code error is now fully understood and has been reproduced in the spacecraft test bed. A decision will be made in the near future whether to correct the flight code or to implement workarounds to prevent the conditions that led to execution of the faulty code. Wednesday, September 14 (DOY 257): An Assessment meeting was held today to review all of the requested changes to the S19 sequence. At this point it looks like all of the changes can be accommodated. If there are no alterations to the recommendations of the Target Working Teams and Orbiter Science Teams, there will be no need to hold the decision meeting on September 27. Cassini Outreach addressed 85 attendees at the NASA Education Professional Development Conference last week. The presentation focused on how the Saturn Observation Campaign members throughout the US could be tapped for Cassini programming and Saturn observing events. Most attendees were Aerospace Education Services Program specialists who deliver NASA's education products and services to different regions of the country. Wrap up: 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. --- To unsubscribe from Cassini Spacecraft Updates, send a message to leave-cassini-@xxxxxxxxxxxxxxxxx --- Visit the JPL Cassini home page for more information about the Cassini Project: <http://saturn.jpl.nasa.gov/>
