Cassini Significant Events 07/23/08 - 07/28/08

July 31, 2008

(Source: Cassini Project)

The most recent spacecraft telemetry was acquired on July 28 from the DSN tracking complex at Goldstone, California. The Cassini spacecraft is in an excellent state of health and all subsystems are operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" page at:

Wednesday, July 23 (Day of Year (DOY) 205):

The DOY 209-210 Saturn/Tethys Live Inertial Vector Propagator (IVP) Update Go/No-Go meeting was held today. A modification to the Tethys vector will be uplinked to the spacecraft on Friday.

Thursday, July 24 (DOY 206):

The Ultraviolet Imaging Spectrograph (UVIS) with Imaging Science (ISS) and Visual and Infrared Mapping Spectrometer (VIMS) riding along performed a slow scan to study Saturn's auroral zone at high latitudes. Hints of auroral patterns that repeat in longitude have previously been detected in high latitude observations. Over the duration of the study, images may show response of the aurora to changes in the solar wind.

Friday, July 25 (DOY 207):

The live update of the Tethys vector for DOY 209-210 was uplinked today. The file is registered on board and will execute on Sunday.

Various instrument teams perform Periodic Instrument Maintenance (PIM) on their instruments in order to keep them operating properly. Today, Radio Science performed a PIM, Ultra Stable Oscillator Characterization, and a boresight calibration. In addition, the team performed an operations readiness test for an upcoming Saturn occultation.

Sunday, July 27 (DOY 209):

Orbit Trim Maneuver (OTM) #160 was performed today. This is the approach maneuver setting up for the Titan 45 encounter on July 30. The reaction control subsystem burn began at 9:00 AM PDT. Telemetry immediately after the maneuver showed the burn duration was 139 seconds, giving a delta-V of 0.169 m/s. All subsystems reported nominal performance after the maneuver.

The main engine (ME) cover was closed at the end of the OTM-160 prime window for a possible dust hazard early Monday. It will be opened July 28 at the start of the OTM-160 backup window. This is the 41st cycle of the ME cover. The next closure is set for Aug. 3.

The Composite Infrared Spectrometer (CIRS) observed the unlit side of Saturn's main rings today to determine how ring temperature varies around the planet. Following this, ISS observed Tethys. VIMS then recorded the disappearance of the star Crucis behind Saturn's rings to investigate how the rings' infrared optical depth varies with distance from Saturn.

Monday, July 28 (DOY 210):

Non-targeted flybys of Pan, Prometheus, and Epimetheus occurred today.

The spacecraft transitioned out of reaction wheel control during a downlink pass to enable the Radio and Plasma Wave Science instrument to perform a search for Whistler activity.

As the optical remote sensing instruments observed stellar occultations and satellite eclipses today, the magnetosphere and plasma science instruments resumed their campaign to study Saturn's aurorae, measuring the properties of that part of the magnetosphere connected to the planet's auroral ovals, and Saturn Kilometric Radiation source regions.