Cassini is orbiting Saturn with a 31.9-day period in a plane inclined 40.3 degrees from the planet's equatorial plane. The most recent spacecraft tracking and telemetry data were obtained on Sept. 23 using the 70 meter diameter Deep Space Network (DSN) station in Spain. The spacecraft continues to be in an excellent state of health with all of its subsystems operating normally except for the instrument issues described at http://saturn.jpl.nasa.gov/news/significantevents/anomalies . Information on the present position of the Cassini spacecraft may be found on "Eyes on the Solar System":

http://1.usa.gov/1pEI4aQ

Wednesday, Sept. 17 (DOY 260)

While gathering speed towards a Friday periapsis, the Ultraviolet Imaging Spectrograph (UVIS) controlled the spacecraft's orientation for close to twelve hours to scan Saturn's thermosphere -- the heated, thin upper atmosphere. Data from this observation will be useful for refining estimates of the gas density there to aid in planning Cassini's 2017 proximal orbits.

Thursday, Sept. 18 (DOY 261)

The Composite Infrared Spectrometer (CIRS) took control of pointing for six hours to carry out a thermal survey of the rings. Next, UVIS mapped the rings to collect spectral data for about eight hours while the Imaging Science Subsystem (ISS), the Visible and Infrared Mapping Spectrometer (VIMS) and CIRS acquired data in ride-along mode.

Friday, Sept. 19 (DOY 262)

The flight team fired Cassini's small rocket thrusters using commands created and uplinked near real time, for Orbit Trim Maneuver (OTM) 391. The commands caused the spacecraft to turn and burn hydrazine for 79 seconds, imparting the desired change in velocity of 85 millimeters per second to fine-tune the approach to Titan.

As soon as the OTM finished executing, VIMS observed a 4.5-hour occultation as the red giant star R Lyrae passed behind Saturn's rings. This star is brighter in infrared light than the well-known star Vega (Alpha Lyrae) is in visible light. ISS and CIRS rode along. With the occultation complete, CIRS made another thermal survey of the rings; this one lasted four hours. Next, VIMS led ISS and CIRS in a 4.5-hour study of the region where Saturn's shadow falls on the rings. Finally, ISS spent an hour re-targeting features known as "propellers" (http://go.usa.gov/YyGR) in the rings. Cassini passed through periapsis at 753,000 kilometers above Saturn's cloud tops, going 30,911 kilometers per hour relative to the planet.

Four moons, which may have a potential for harboring some sort of life, appeared in NASA's Astronomy Picture of the Day today. Two of them, the 5,152 kilometer diameter Titan, and the 504 kilometer wide Enceladus, are targets that Cassini regularly studies:

Originally posted here:

NASA Cassini Significant Events 09/17/2014 - 09/23/2014