Cassini Significant Events
07/09/08 - 07/15/08
The most recent spacecraft telemetry was acquired on July 15 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:
http://saturn.jpl.nasa.gov/operations/present-position.cfm.
Wednesday, July 9 (Day of Year (DOY) 191)
A Spacecraft AACS Periodic Engineering Maintenance (PEM) occurred
July 9, 2008. Performed every 90 days, this activity exercises the
Engine Gimbal Actuators and the back-up Reaction Wheel Assembly (RWA)
#3. In the RWA exercise, the wheel is commanded to +100 rpm, -100
rpm, 0 rpm, then turned off.
Composite Infrared Spectrometer (CIRS), Imaging Science (ISS), and
Visual and Infrared Mapping Spectrometer (VIMS) teams have concurred
with Science Planning that the DOY 196 and DY 202 Live Inertial
Vector Propagator (IVP) update should occur, so the sequence leads
cancelled the Go/No-Go meeting scheduled for today and are proceeding
with generating the Live IVP Update sequence products.
It has been confirmed that the spacecraft has received the V12.2
update to Cosmic Dust Analyzer (CDA) Flight Software (FSW).
Following that confirmation, commands were sent modifying the Science
and Engineering Rate-2 (S&ER) data collection rate that will support
this new version of instrument FSW, and for the DOY 194 FSW checkout,
and DOY 196 ring plane crossing demonstration.
Thursday, July 10 (DOY 192)
The Instrument Operations Multi-Mission Image Processing Laboratory
experienced two hardware glitches on mipl8, the multi-mission server
which hosts Cassini's database essential for automation, product
generation, and data delivery functions. The first problem caused by
a disk controller failure occurred Thursday at 3:20 pm. Services
were restored by 11:00 pm that night. The second problem caused by
a spontaneous reboot occurred at 10:50 pm Friday. All services were
restored by Saturday at 1:00 am. Both incidents required significant
off-shift support. Thanks to team support and dedication, Cassini
was able to resume processing and satisfy all product delivery
performance requirements in this period despite the hardware issues.
Friday, July 11 (DOY 193)
The files for both the DOY 196 Saturn/Janus/Rhea/Mimas live update
and the DOY 202 Saturn/Dione live update were uplinked to the
spacecraft today. All files have been registered and activated on
board. They currently await their absolute start time to begin
execution.
JPL is now using the micro-blogging site "Twitter" to give regular
updates about its missions. For Cassini, the user submits a question
or message and members of the flight team respond from the
perspective of the spacecraft. If you go to the following link, you
can subscribe to the Cassini Mission updates by clicking "follow" and
can review some of the messages sent by the "spacecraft" thus far:
http://twitter.com/CassiniSaturn
Monday, July 14 (DOY 196)
Non-targeted flybys occurred today of Daphnis, Prometheus, and Pallene.
As the spacecraft approaches periapsis, CIRS leads a series of joint
Optical Remote Sensing (ORS) icy satellite observations. The targets
include Janus, an Enceladus solar eclipse, and a Rhea solar eclipse.
Just prior to periapsis, the Ultraviolet Imaging Spectrograph (UVIS)
observes the ingress of a solar occultation of Saturn, is followed by
VIMS taking high-phase images of the rings, which in turn is followed
by UVIS observing the Saturn solar occultation egress. After
periapsis, CIRS turns the spacecraft's attention to a solar
occultation of Mimas with the other ORS instruments riding along.
ISS and VIMS wrap up the day imaging Saturn's south polar vortex.
A new JPL blog features scientists and engineers who will offer
insights into their areas of expertise - ranging from Mars, Saturn
and other solar system bodies to the universe beyond. Meet Cassini
Equinox Mission Project Scientist Bob Pappalardo in the first blog
entry on July 14. http://blogs.jpl.nasa.gov/
Tuesday, July 15 (DOY 197)
A non-targeted flyby of Titan occurred today.
At the weekly Operations Status and Coordination Meeting, members of
the CDA instrument team reported that last Friday's instrument
checkout went just fine. At this time they are waiting for the
playback of yesterday's ring plane crossing demonstration to be able
to analyze the results. If all goes well, files for two additional
tests will be uplinked in the upcoming week.
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