From: Jet Propulsion Laboratory
Posted: Friday, February 22, 2008
The most recent spacecraft telemetry was acquired on Tuesday, February 19, from the Madrid 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, February 13 (DOY 044):
The S38 background sequence was uplinked to the spacecraft today. The sequence will begin execution this Saturday. Science observations from now until the end of S37 include the Ultraviolet Imaging Spectrograph (UVIS) performing a series of three long mosaic observations while the spacecraft is at apoapse. The observations, which will take 13.5 hours, 12.75 hours, and 13.5 hours again, will aim the UVIS Extreme Ultraviolet and Far Ultraviolet low-resolution slits toward Saturn, perpendicular to the orbital plane, and then drift around the spacecraft Z-axis to scan. After multiple orientations and drifts, Cassini will slew back to point at Saturn's center and stare for the remaining observation time.
The JPL Media Relations Office produced a news release on Titan's organics. Titan has hundreds of times more liquid hydrocarbons than all the known oil and natural gas reserves on Earth, according to new data from Cassini. The hydrocarbons rain from the sky, collecting in vast deposits that form lakes and dunes. The new findings are reported in the Jan. 29 issue of the Geophysical Research Letters. For the entire release, link to: http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=814 An encounter strategy meeting was held today to cover the period between Feb. 22 and Mar. 13, Titan flyby T41 and Enceladus flyby E3, and maneuvers 146-148.
The Target Working Team / Orbiter Science Team integrated products for S43 were delivered today. The Science Operations Plan (SOP) Integration process for S43 will begin Tuesday, Feb. 19, when the Science Planning - spacecraft - Attitude Spread Sheet and Sequence Phase List of Ancillary Files products will be delivered, and the final Cassini request for DSN coverage during execution will be sent to the DSN schedulers. Execution begins on Aug. 11 of this year.
Thursday, February 14 (DOY 045):
A meeting was held today concerning the orbit determination (OD) solution to be used for the DOY 059-066 Saturn/Dione/Tethys Live Inertial Vector Propagator (IVP) update and the DOY 062 Radio Science (RSS)/UVIS ring occultation Live Movable Block (LMB). Navigation (NAV) looked at the uncertainties in the solution for Orbit Trim Maneuver (OTM)-145 and declared it would not be a good OD solution choice for this update. It was decided at this meeting that NAV would generate a special pre-Titan 41 OD solution that would be available on Feb. 21, which should be in time for generating the IVP update and LMB sequences. The sequence leads will generate a schedule for the update process shortly and see if there are any significant specific impacts to the sequence generation process.
Saturday, February 16 (DOY 047):
Science activities at the start of S38 begin with Magnetospheric and Plasma Science (MAPS) instruments continuing to observe the magnetospheric boundaries near noon on highly inclined orbits. Later this week the Visual and Infrared Mapping Spectrometer (VIMS) will stare at one ansa of the F ring and observe continuously for one orbital period to build up a 360 deg azimuthal map of the ring, and Imaging Science (ISS) will lead a joint Optical Remote Sensing (ORS) campaign to observe the north pole. Meanwhile the MAPS teams will be conducting a campaign of their own to study the dynamics of Saturn's inner magnetosphere.
The S37 sequence concluded and S38 began execution today at 2008-047T11:51:00 SCET. The sequence will run for 36 days and conclude on Mar. 23. During that time there will be two targeted encounters, one of Titan and one of Enceladus. The Enceladus flyby will be the closest flyby in the mission so far, coming within 50 km at closest approach and around 200 km as Cassini skirts the edges of the plumes. Also in S38 there will be two non-targeted flybys each of Prometheus and Daphnis, and one each of Pan, Pandora, Janus, and Titan. Seven OTMs are scheduled, numbered 145 through 151.
Tuesday, February 19 (DOY 050):
The JPL Media Relations Office issued a news release on a special February issue of Icarus featuring 14 Cassini papers on Saturn's icy moons. Despite the incredible diversity of Saturn's icy moons, theirs is a story of great interaction. Some of them are pock-marked, some seemingly dirty, others pristine, one spongy, one two-faced, some still spewing with activity and some seeming to be captured from the far reaches of the solar system. Yet many of them have a common thread -- black "stuff" coating their surfaces.
For the full release on the Cassini web site link to: http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=816. Gaps in the soup of high-energy particles near the orbits of two of Saturn's tiny moons indicate that Saturn may be surrounded by undiscovered, near-invisible partial rings. A paper in the February issue of the journal Icarus suggests the larger Saturnian moons may not be the only ones contributing material to Saturn's ring system. For the full story link to: http://saturn.jpl.nasa.gov/news/features/feature20080219.cfm. Orbit Trim Maneuver (OTM) #145 was performed today. This is the approach maneuver setting up for the Titan 41 encounter on Feb. 22. The main engine burn began at 1:45 AM PST. Telemetry immediately after the maneuver showed the burn duration was 1.725 seconds, giving a delta-V of 0.279 m/s. All subsystems reported nominal performance after the maneuver. All participating teams made the preliminary port delivery as part of the S41 Science Operations Plan Update process. The SOPU process completes Mar. 14 and will be followed by final sequence development for this last prime mission sequence.
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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