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Cassini Significant Events 06/13/2012 – 06/19/2012

The most recent spacecraft tracking and telemetry data were collected on June 20 by the Deep Space Network's 34 meter Station 15 at Goldstone, California. Aside from CAPS, which is off, and the Ultrastable Oscillator (see the Jan. 5, 2012 Significant Events), the Cassini spacecraft is in an excellent state of health with all its subsystems operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at:

The S73 on-board command sequence completed execution and S74 began running on Monday afternoon; it will control the spacecraft through Aug. 25. While still running S73 commands this week, the Imaging Science Subsystem (ISS), the Composite Infrared Spectrometer (CIRS), and the Visible and Infrared Mapping Spectrometer (VIMS) performed two Titan monitoring campaign observations, and ISS accomplished two observations in the Satellite Orbit Campaign. More details about these campaigns appear in previous weeks' reports.

Wednesday, June 13 (DOY 165)

CIRS completed a 33.5 hour mid-infrared map of Saturn to determine upper troposphere and tropopause temperature. The Cosmic Dust Analyzer (CDA) began a 37.5 hour interstellar dust observation.

The Attitude and Articulation Control Subsystem (AACS) team performed a Reaction Wheel Assembly (RWA) bias maneuver. While off Earth-point and not being tracked, thrusters stabilized the spacecraft so the RWA speeds could be adjusted.

A feature titled, "Cassini Sees Tropical Lakes on Saturn Moon" was published today, describing methane lakes located far from Titan's poles. It may be viewed here:

Thursday, June 14 (DOY 166)

The Realtime Operations team uplinked the S74 background sequence this evening using the 70 meter DSN station at Canberra, Australia. All of the 9488 commands were confirmed onboard the spacecraft after a round-trip light time of 2 hours 32 minutes.

Friday, June 15 (DOY 167)

CIRS began another mid-infrared map of Saturn; this one lasted 23 hours.

Saturday, June 16 (DOY 168)

ISS performed a 10 hour satellite search around the Titan L5 Lagrange point 60 degrees behind Titan where it is possible for objects to exist in orbital equilibrium.

Sunday, June 17 (DOY 169)

Taking advantage of its 2.9 million kilometer distance from Saturn, CDA began another interstellar dust observation; it executed for 23.5 hours.

Cassini passed through apoapsis today going 5680 kilometers per hour relative to Saturn. This marked the start of orbit #168, which has a period of 24.9 days and an inclination of 21.1 degrees.

A 34 meter Deep Space Network (DSN) station at Canberra, Australia, participated in an Operations Readiness Test (ORT) in preparation for the Radio Science ring occultation experiment coming up on June 28. This was the third such ORT this week involving various Canberra DSN stations.

Monday, June 18 (DOY 170)

An RWA bias maneuver was executed via realtime command in preparation for the new background sequence. AACS then executed its Periodic Engineering Maintenance, which included spinning RWA3 to + and - 100 rpm for lubrication purposes, and a main–engine gimbal assembly exercise.

This afternoon the S74 Sequence began executing on the spacecraft.

An image of Titan blocking the Sun, titled "Hazy Ring", was featured today. It may be viewed here:

Tuesday, June 19 (DOY 171)

VIMS, CIRS, ISS and UVIS jointly observed the dark side of Saturn's rings for 12 hours.

The Spacecraft Operations Office held a review of plans for powering on Deep Space Transponder B, the spacecraft's redundant radio receiver, for troubleshooting the apparently anomalous Ultrastable Oscillator early next month.