NASA Cassini Significant Events for 03/19/2014 – 03/25/2014
Cassini is orbiting Saturn with a 31.9-day period in a plane inclined 45.5 degrees from the planet’s equatorial plane. The most recent spacecraft tracking and telemetry data were obtained on March 25 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.”
While Cassini rounded the top of its Saturn orbit, at a distance of 1.38 billion kilometers from Earth, the Deep Space Network spent a total of 43.3 hours linking with Cassini during seven sessions this week, providing nearly flawless two-way digital communications and radiometric tracking services.
Wednesday, March 19 (DOY 078)
The Visible and Infrared Mapping Spectrometer (VIMS) controlled the spacecraft’s pointing for 6.5 hours to compile a map of the northern polar aurorae. Meanwhile, the other Optical Remote-Sensing (ORS) instruments, which are the Imaging Science Subsystem (ISS), the Composite Infrared Spectrometer (CIRS), and the Ultraviolet Imaging Spectrograph (UVIS), also acquired data to store on Cassini’s solid-state recorder. Next, UVIS led CIRS and VIMS in observations across the auroral oval for another 6.5 hours.
Thursday, March 20 (DOY 079)
UVIS conducted a 13.7-hour observation of Saturn in the far- and extreme-ultraviolet, with ISS riding along to take visible-light images. At about the same time, the flight team was preparing commands for Orbit Trim Maneuver (OTM)-375. This OTM executed out near apoapsis, taking advantage of the orbital-mechanics “leverage” available there. The OTM commands turned the spacecraft and fired the main engine for three seconds, producing the desired 0.54 meter per second change in the spacecraft’s velocity to set up Cassini’s flight path for the next Titan flyby, T-100, on April 7.
Friday, March 21 (DOY 080)
CIRS began a 22-hour long observation using its mid-infrared sensor to map Saturn’s atmosphere.
Saturday, March 22 (DOY 081)
CIRS retained control of pointing for another 14 hours for an observation of Saturn’s atmosphere to better define its composition, with the other ORS instruments also taking part. The observation was repeated on Monday for 16 hours.
Sunday, March 23 (DOY 082)
Taking advantage of Cassini’s distance from Saturn, the Cosmic Dust Analyzer (CDA) started a 20-hour long observation of interstellar dust, characterizing each particle that entered the instrument.
Monday, March 24 (DOY 083)
Cassini coasted through apoapsis today at a distance of three million kilometers from Saturn, having slowed to 8,487 kilometers per hour relative to the planet. This marked the start of orbit #203.
The Saturn system is a laboratory for investigating orbital interactions. Four moons that are now well-known for their gravitational interactions can be identified in the extraordinary image featured today (click through to the full-resolution image to see the little moons): http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=4998
Tuesday, March 25 (DOY 084)
With CIRS riding along, VIMS observed the red star Lambda Velorum for almost 25 hours as it made a slow chord occultation of Saturn’s ring system from the F ring in to the middle-B ring and back out to the F ring. This occultation geometry promised high-spatial-resolution measurements of the rings.
