From: Jet Propulsion Laboratory
Posted: Saturday, January 18, 2014
Cassini is orbiting Saturn with a 31.9-day period in a plane inclined 50.1 degrees from the planet's equatorial plane. The most recent spacecraft tracking and telemetry data were obtained on Jan. 8 using the 70-meter diameter Deep Space Network station at Canberra, Australia. 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" at
The on-board S82 command sequence controlled most of the spacecraft's activities this week. One exception was the real time commanding for Orbit Trim Maneuver 368. Meanwhile, Cassini's Sequence Implementation Process teams continued working on the ten-week command sequences S83 and S84. Tasks and meetings were set for S85 development. Planning also proceeded for the 2016 start of the F-ring and Proximal Orbits phase.
Wednesday, Jan. 1 (DOY 001)
Today Cassini came within 1,400 kilometers of Titan's shrouded surface, going 21,240 kilometers per hour relative to the 5,152-kilometer diameter planet-like moon. The T-97 flyby page describes the encounter activities: http://saturn.jpl.nasa.gov/mission/flybys/titan20140101. In addition to the science data that Cassini's instruments collected, the encounter was used to shape the spacecraft's orbit about Saturn in compliance with the mission plan. Today's gravity assist reduced Cassini's orbital inclination from 53.1 degrees to 50.1 degrees with reference to Saturn's equatorial plane. The orbit period of 31.9 days did not change.
Thursday, Jan. 2 (DOY 002)
With its telescopes still trained on a fast-receding Titan, the Ultraviolet Imaging Spectrograph (UVIS) studied its atmosphere in the extreme-ultraviolet and the far-ultraviolet; the Visible and Infrared Mapping Spectrometer (VIMS) also took data. The Composite Infrared Spectrometer (CIRS) conducted far-infrared and mid-infrared limb-sounding near the equator to measure gases and aerosols; VIMS and the Imaging Science Subsystem (ISS) also recorded data. Finally, the spacecraft turned to point its high-gain antenna to Earth, and communicated with the 70-meter diameter Deep Space Network (DSN) stations in Australia and Spain for 13 hours, returning all the T-97 science observation data in telemetry at up to 124,426 bits per second.
Last week the Top Ten images for 2013 were featured. Today's announcement revealed the Top Ten science highlights for the year:
Friday, Jan. 3 (DOY 003)
UVIS, CIRS and VIMS began a 10-hour observation of Saturn's southern aurora. Four hours into the observation the spacecraft passed through periapsis of its orbit #200, at about 1.1 million kilometers above the planet. It had sped up to 25,371 kilometers per hour relative to Saturn, more than twice its speed at apoapsis back on December 17.
VIMS observed the red star R Lyrae for four hours as it was occulted by the rings. ISS then made an observation in the Satellite Orbit Campaign, looking at small objects near Saturn. Finally, CIRS started a 10-hour observation of the rings to take measurements of the ring particles' composition. ISS and VIMS rode along taking data while CIRS controlled the pointing.
Saturday, Jan. 4 (DOY 004)
The Attitude and Articulation Control Subsystem's reaction wheels continued to carry out CIRS's requested pointing, this time to map the ring temperatures in Saturn's shadow. The far-infrared observation will aid in determining the thermal inertia of the ring particles.
Sunday, Jan. 5 (DOY 005)
VIMS made a two-minute storm-watch observation on Saturn. ISS then took images of the dark face of the rings for five and a half hours to make a movie of the "spokes" (http://go.usa.gov/4WGP) at high phase-angle illumination in search of spoke periodicities.
Based on the latest DSN tracking data and the navigation team's orbit-determination solutions, the flight team designed and uplinked commands for Orbit Trim Maneuver (OTM) 368. As the commands took effect, the spacecraft turned and fired its small thrusters for 99 seconds. The resulting change in velocity of 101 millimeters per second served to clean up the spacecraft's post-T-97 trajectory and set up for the T-98 Titan flyby on Feb. 2.
Following the OTM's nine-hour DSN session, Cassini turned to train ISS's wide-angle camera on the faint, inclined Phoebe ring at a point where the edge of Saturn's shadow was projecting into the distant ring material. The observation lasted fifteen hours.
Monday, Jan. 6 (DOY 006)
Saturn's little moon Janus, 179 kilometers in diameter, is not quite spherical. It orbits in between the F ring and the G ring, and was featured in a distant view today:
Tuesday, Jan. 7 (DOY 007)
The Magnetospheric and Plasma Science (MAPS) instruments took control of the spacecraft's pointing to begin a 35-hour magnetotail and plasma flow observation.
Visit the JPL Cassini home page for more information about the Cassini Project: http://saturn.jpl.nasa.gov/
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