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

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

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

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.

Visit the JPL Cassini home page for more information about the
Cassini Project: