Cassini is orbiting Saturn with a 35.8-day period in a plane inclined 40.7 degrees from the planet's equatorial plane. The most recent spacecraft tracking and telemetry data were obtained on May 7 using one of the 34-meter diameter Deep Space Network stations at Goldstone, California. Except for the science instrument issues described in previous reports (for more information search the Cassini website for "CAPS" and "USO"), the spacecraft continues to be in an excellent state of health with all of its subsystems operating normally. Information on the present position of the Cassini spacecraft may be found on "Eyes on the Solar System."
Picking up speed relative to the planet (but feeling no acceleration effect of course), Cassini spent the week falling inward along its orbit toward Saturn. Along the way it made some long-duration science observations, as well as some shorter ones.
Wednesday, April 30 (DOY 120)
The Magnetospheric Imaging Instrument (MIMI) continued a 34-hour long observation of Saturn's northern aurora.
Thursday, May 1 (DOY 121)
Though not often recounted in these reports, Cassini's Attitude and Articulation Control Subsystem regularly stabilizes the spacecraft for short periods using its small rocket thrusters while it sets the electrically-driven reaction wheels to appropriate speeds; one such maneuver executed today and another again on Monday. In addition, Cassini's science teams routinely put their instruments through numerous calibration exercises to ensure that their scientific data return can be accurately validated. Following today's reaction-wheel bias event, the Visible and Infrared Mapping Spectrometer (VIMS) spent two hours with its telescope trained on well-known reddish stars in order to calibrate the instrument; first was the star L2 Puppis and then it was Sigma Puppis. When this activity finished, the Cosmic Dust Analyzer (CDA) began a 35-hour long observation, collecting and reporting on dust that orbits Saturn in the retrograde direction. (CDA can determine a dust particle's mass, electrical charge, direction of flight, velocity, and chemical composition.)
Members of Cassini's Executive Staff conducted a peer-review with other JPL experts today to discuss plans for Cassini's Proximal Orbit mission segment, which is expected to begin in April 2017.
Friday, May 2 (DOY 122)
The Deep Space Network (DSN) carried out four sessions dedicated to Cassini this week, providing two-way digital communications and radiometric tracking. During two of these, the stations also participated in operations-readiness testing in preparation for a complicated Radio Science experiment coming up on May 17 during the Titan T-101 encounter.
Saturday, May 3 (DOY 123)
The Imaging Science Subsystem (ISS), along with VIMS and the Composite Infrared Spectrometer (CIRS), performed a 1.5-hour observation in the Titan monitoring campaign from a distance of three million kilometers. ISS then spent one hour in the Satellite Orbit Campaign looking for objects near the planet. VIMS then squeezed in a two-minute Saturn storm-watch observation. Finally, the Magnetometer took control of the spacecraft and had it pitching slowly about its X-axis for 25 hours. This was another type of science instrument calibration that is often repeated.
Sunday, May 4 (DOY 124)
ISS, CIRS and VIMS spent another 1.5 hours monitoring Titan, this time from 2.3 million kilometers away.
Monday, May 5 (DOY 125)
MIMI began an observation of the solar wind that would last 37.33 hours.
Back at JPL, new telemetry-display files were installed on the flight team's computer workstations, as well as upstream in some of the software that interfaces Cassini with the DSN. These changes will accommodate new capabilities that are going to be implemented on one of the spacecraft's science instruments.
Saturn's massive moon Titan almost seems to have its own little moon in an unusual image featured today: http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=5024
Tuesday, May 6 (DOY 126)
Using one of the 34-meter diameter DSN stations in California, the flight team tonight began the process of sending commands to install new flight software on the spacecraft for the CIRS instrument. After a round-trip light time of two hours and 28 minutes, telemetry confirmed that each one of the 2,419 individual commands was properly received and stored on board in Cassini’s Solid State Recorder.
Saturn is nearing opposition in Earth's night sky, and presenting a fine view in almost any small telescope. See JPL's "What's Up" video at: http://youtu.be/4mxFlUCliWg