Cassini Weekly Significant Events for 01/24/02 – 01/30/02
The most recent spacecraft telemetry was acquired from the Goldstone
tracking station on Wednesday, January 30. The Cassini spacecraft is in
an excellent state of health and is operating normally. “Present
Position” web page, http://www.jpl.nasa.gov/cassini/english/where/ ..
The C30 sequence continues to execute as planned. Science activities
this week include acquisition of the second set of images in support of
the Imaging Science Subsystem (ISS) decontamination mini-sequence, and
uplink and execution of a modification to the VIMS Image/Occultation
mini-sequence. Twenty decontamination images were obtained as part of
last week’s ISS observations. Although the images obtained provided the
desired information, the star Spica was found to be off center of frame
by about 30%. The ISS team will correct this for future decontamination
activities.
Spacecraft activities included clearing of the AACS High Water Marks and
a system command to reset the SSPS trip counter. In support of a Deep
Space Network (DSN) request to test a new version of their firmware, an
Immediate/Delayed Action Program (IDAP) was executed, putting Cassini
into 82K downlink mode over DSS-15, and returning to S&ER3 near the end
of the pass. Mission Support and Services Office personnel reported
that despite early indications that the test was successful, not all
test objectives were met. After further analysis, DSN personnel have
determined that additional test support will be requested.
The Sequence Change Request approval meeting for C31 was held this week.
The
Spacecraft Activity Sequence Files (SASF) were integrated and the
preliminary Sequence Integration & Validation (SIV) files were
released. It has been determined that sequence simulation will not be
required for the C31 background sequence. As a result, the simulation
requirements meeting and simulation procedure review meeting have been
cancelled.
Science Planning (SP) chaired a Project briefing for C32 to approve the
integrated product for implementation. The Program Manager approved the
current contents of the plan. Other activities included a half-day SOST
meeting to continue work on the SOST-assigned tour segments in orbits 11
and 12, and Target Working Team meetings to work towards the next
integration milestone. This milestone includes orbits 10 through 15.
Members of the JPL Planetary Data System Imaging node met with members
of the
Imaging Science Subsystem team at the Southwest Research Institute
(SWRI) in Boulder, CO to discuss archiving. The meeting was very
successful in that Imaging node software was identified that may be
transported to SWRI. This software will automate a considerable portion
of the image archiving process. Groundwork has now been laid to
establish a pipeline that can be tested, and archiving of the Jupiter
flyby data should be completed before the scheduled deadline.
A Ground Data System 10 bps telemetry rate DTF-21 dataflow test was
performed this week. The test is in support of a CDS flight software
patch to be uplinked in early February. Preliminary test reports
indicate nominal results; however, additional analysis is still
pending. MSSO chaired an ITAR, MSSO, and Program discussion. A few of
the issues covered were access to JPL networks, remote access by foreign
nationals, and ITAR log keeping requirements. This meeting will be held
quarterly to assess the current situation.
Mission Assurance attended the JPL Project Risk Management Class and
gave a
presentation illustrating the Cassini approach to Risk Management during
Mission
Operations. Mission Assurance has aggressively worked the closure of
Incident Surprise Anomaly (ISA) reports with the Cassini Office
Managers. To date, 48 ISAs have been resolved and closed during the
month of January. Plans are to work ISAs on a regular, systematic
basis, to ensure that issues are given adequate attention in a timely
manner and are resolved promptly, where possible.
Mission Planning (MP) received a proposed flight rule from the Composite
Infrared Spectrometer (CIRS) instrument team indicating allowable dust
damage at Saturn for the CIRS instrument. MP coded the flight rule and
began assessing its effects on science sequencing.
Topics at the Mission Planning Forum this week included discussion of
the addition of a maneuver window to the baseline after the SOI – 15 day
burn, and determination if a credible failure exists which would keep us
from executing the T – 3 day trajectory correction maneuver.
Cassini is a cooperative project of NASA, the European Space Agency and
the Italian Space Agency. The Jet Propulsion Laboratory, a division of
the California Institute of Technology in Pasadena, Calif., manages the
Cassini mission for NASA’s Office of Space Science, Washington, D.C.
