The most recent spacecraft telemetry was acquired on Jan. 19 from the
Deep Space Network tracking complex at Madrid, Spain. The Cassini
spacecraft is in an excellent state of health and all subsystems are
operating normally.
Wednesday, Jan. 13 (DOY 013)
The Science Operations Plan process (SOP) for S61, the first of the
"bridge sequences," kicked off today.
Back in 2007, prior to NASA approval of the Equinox Extended Mission
(XM), it was necessary to begin development for that mission so that
if approved, execution could proceed on schedule. At that time, it
was decided to leave the final three sequences of XM indefinite and
firm them up at a later time.
Now that Cassini is waiting for approval of an Extended Extended
Solstice Mission (XXM), these final sequences of XM, S61, S62, and
S63 have been defined, segmented and designated the bridge sequences
to bridge between XM and the proposed XXM. Should XXM be approved,
S64-S67 would become the "transition sequences." To meet a goal of a
50% reduction in workforce, the Sequence Integration Process (SIP)
was developed for XXM to replace the SOP and Science and Sequence
Update (SSUP) processes. Between S64 and S68, the development
process was shortened from 24 weeks to 20, and sequence execution
extended from 5 to 10 weeks. These three changes were part of what
enabled the Project to drop from six parallel processes to three, and
thus achieve the target reduction in workforce.
Thursday, Jan. 14 (DOY 014)
Files were due today from all participating teams for the second
input port of the S60 SOP process. The files will be merged Monday
and products sent out for review that same day.
The S57 final sequence approval meeting was held today. The
background sequence will go up to the spacecraft on Tuesday, Jan. 19,
and will begin execution on Saturday, Jan. 23.
The Huygens probe parachuted down to the surface of Titan exactly
five years ago today on Jan. 14, 2005, providing data that scientists
are still building upon today. The Huygens probe, built and managed
by the European Space Agency, was bolted to Cassini and rode along
during the nearly seven-year journey to Saturn. Huygens' descent
marked the first and only attempt to land a probe on another world in
the outer solar system. For the complete story link to:
http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20100114/
Friday, Jan. 15 (DOY 015)
Orbit Trim Maneuver (OTM) #233 was performed today. This was the
cleanup maneuver from the Titan 65 encounter on Jan. 12. The main
engine burn began at 10:14 PM PST. Telemetry immediately after the
maneuver showed a burn duration of 13.33 seconds, giving a delta-V of
2.26 m/s. All subsystems reported nominal performance after the
maneuver.
Monday, Jan. 18 (DOY 018):
All Instrument Expanded Block files for S57 were uplinked to the
spacecraft and verified over the weekend.
Today was a calibration day for some of the instruments. The
Composite Infrared Spectrometer (CIRS) started off with an activity
called a "Scattered Sunlight Test." This activity quantified the
effect of ring particle impacts on the mirror performance by
monitoring scattered infrared solar radiation as a function of offset
angle from the sun. RADAR was next with a Radiometric Microwave
Sources Calibration. This activity was performed by pointing the
RADAR antenna, co-aligned with Cassini's high gain antenna, towards
the Sun, Saturn, and various other known microwave sources.
Tuesday, Jan. 19 (DOY 019)
CIRS performed a noise test today. Files were uplinked last Thursday
to patch CIRS flight software and collect science data to see if
changes in the software would eliminate internal instrument generated
noise. At the end of the test the flight software was patched back
to the current version.
A hydrazine and deltaV consumables update was given today by Mission
Planning at the Mission Planning Forum. Mission Planning, the
Spacecraft Office, and the Program Office monitor these two
consumables very carefully to ensure enough remains to carry out the
mission as designed. At the presentation a discussion was held on
how to re-evaluate as-flown usage and strategically plan for future
sequences.
This week as Cassini approached Saturn apoapsis, observations that
took advantage of the wide special coverage provided by the large
distance from Saturn were common. One of these observations, the
Ultraviolet Imaging Spectrograph "apo-mosaic", performed several
times throughout the week, produced mosaic scans of Saturn's
magnetosphere.
Additional observations included Imaging Science monitoring of Titan,
a Satellite Orbit Campaign, and imaging of the mutual transit of
Epimetheus across Janus. These "mutual events", as they are called,
help determine the orbits for both objects. The Cassini Plasma
Spectrometer was prime during a period of Saturn magnetospheric
measurement, and CIRS pointed towards several infrared stars as part
of a long-term effort to monitor them.
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