From: Jet Propulsion Laboratory
Posted: Friday, July 11, 2008
The most recent spacecraft telemetry was acquired on July 8 from the DSN tracking complex at Goldstone, California. 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" page at: http://saturn.jpl.nasa.gov/operations/present-position.cfm.
Saturday, June 28 (Day of Year (DOY) 180):
A non-targeted flyby of Titan occurred on June 28. In addition, non-targeted flybys of Prometheus, Enceladus, Janus, Methone and Atlas will occur on June 30, and of Janus, Pandora and Methone on July 7.
Monday, June 30 (DOY 182):
Another important milestone occurred today in the implementation of the Cassini extended mission. The final integrated S47 sequence segments, which include orbits 99 through 103, were delivered today. S47 executes from Jan. 9 to Feb. 17, 2009. Between now and then, the Science Operations Plan process and Science and Sequence Update process must be completed in order to create a sequence that then can be approved and flown on the spacecraft. As of today, scientists will begin working on their pointing designs. The final Cassini Deep Space Network (DSN) station requests for January and February will be delivered to the DSN schedulers on July 7.
All participating teams have given their go-ahead for the DOY 188 Live Inertial Vector Propagator (IVP) update and DOY 189 Radio Science (RSS) Live Movable Block update. Uplink Operations will now build the files that will be sent to the spacecraft on July 2.
The final science of the prime mission included an RSS Gravity Science experiment, a Radio and Plasma Wave Science (RPWS) auroral crossing observation, and instrument observations of the rings, Mimas, Enceladus, Janus and Tethys.
Tuesday, July 1 (DOY 183):
Today is a big day in the life of the Cassini Program. It is the 4th anniversary of the July 1, 2004 Saturn Orbit Insertion, the end of the Prime Mission, the start of the Cassini Equinox Mission and the start of execution of the first extended mission sequence, S42.
The S41 sequence concluded and S42 began execution today at 2008-83T19:08 SCET. The sequence will run for 40 days, concluding Aug. 11. During that time, there will be one targeted encounter of Titan and 16 non-targeted flybys -- two each of Daphnis, Prometheus, Pallene, Pan, and Epimetheus, and one each of Titan, Atlas, Mimas, Janus, Pandora and Methone. Three Orbit Trim Maneuvers (OTM) are scheduled, numbered 160, 162 and 163.
Just as Cassini is about to launch a new phase of its tour of Saturn, the interactive Cassini at Saturn Interactive Explorer (CASSIE) has gotten a significant upgrade. Version 2 makes it easier to navigate through time and view significant mission events. There are now cameras "stationed" near seven of Saturn's moons so the viewer can watch events from a different perspective. An artificial, dual-power "Laser Range Finder" has been added to measure distances between Cassini and its targets and to allow the user to temporarily "leave your mark" on Saturn's moons. CASSIE makes real Cassini mission data fully available in three colorful, easy-to-use expeditions. The new tool is online at: http://saturn.jpl.nasa.gov/multimedia/CASSIE/
Wednesday, July 2 (DOY 184):
The first update files for S42 were uplinked to the spacecraft today. These include a DOY 188-190 Saturn/Enceladus Live Inertial Vector Propagator Update sequence that will begin execution on Sunday, and DOY 189 RSS Saturn occultation LMB that will execute on Monday.
Science observations for S42 occur during orbits 74 thru 80 at a high-inclination angle. This geometry will allow Imaging Science (ISS) to obtain full coverage of ringlets and gaps in the C- and D-rings, which is not possible in lower-inclination orbits. Highlights this week include an ISS spoke movie on DOY 184, a Visual and Infrared Mapping Spectrometer (VIMS) F-ring movie on DOY 187, and three star occultations on DOY 188, 190 and 191.
During the Cassini Equinox Mission, a great deal of Rings Target Working Team attention will be focused on the F-Ring, studying its transient structures and looking for the bodies that create near-constant disruptions of those structures. The Rings group will be using several bright infrared and ultraviolet stars to probe the densest portions of the ring system, the Composite Infrared Spectrometer (CIRS) will continue with thermal studies, and VIMS will continue with studies of ring composition.
Monday, July 7 (DOY 189):
The Science Operations Plan process for S44 completed today. Tomorrow, Science Planning and Uplink Operations will hold the hand-off meeting that begins the final development process for this sequence. S44 will begin execution on Sept. 13.
Tuesday, July 8 (DOY 190):
On July 8, Uplink Operations began sending a number of files to the spacecraft in support of a new Flight Software (FSW) update for the Cosmic Dust Analyzer (CDA). The update is desired for the Enceladus-4 targeted encounter on Aug. 11. Instrument FSW version 12.2 was sent to the spacecraft today. Over the next three days, additional files will be sent for a flight software checkout activity, and the first of two FSW demonstrations, this one for a ring-plane crossing. The instrument checkout will execute on July 11.
The Live Update train just keeps steaming along. Since both the Saturn/Janus/Rhea/Mimas update on DOY 196, and the Saturn/Dione update on DOY 203 use the orbit determination solution being released today, the sequence leads have combined the two activities into one process. The kick-off meeting occurred today and the Go/No-Go meeting is scheduled for tomorrow for input from CIRS, ISS, VIMS, Spacecraft Operations, Science Planning and Navigation.
Visit the JPL Cassini home page for more information about the Cassini Project: http://saturn.jpl.nasa.gov/
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