NASA Cassini Significant Events for 05/13/04 – 05/19/04
The most recent spacecraft telemetry was acquired from the Goldstone
tracking station on Wednesday, May 19. The Cassini spacecraft is in an
excellent state of health and is operating normally. Information on the
present position and speed of the Cassini spacecraft may be found on the
“Present Position” web page located at
http://saturn.jpl.nasa.gov/operations/present-position.cfm .
After activating, loading instrument expanded blocks, and initializing
various instruments, S01, the first tour sequence, began data collection
activities. Unique activities in S01 include trajectory correction
maneuvers 20 and 21, the first Inertial Vector Propagator (IVP) live update,
and the only Phoebe encounter in the tour.
On-board activities this week included the Imaging Science Subsystem (ISS)
Titan movie, which searches for evidence of cloud motion to measure winds.
ISS also continued to study the orbits of the known satellites to improve
understanding of short- and long-term dynamical evolution. The Ultraviolet
Imaging Spectrograph (UVIS) continues to map the Saturn magnetosphere in
neutral and ion photon emissions to derive the distribution and density of
atomic and molecular species. The Composite and Infrared Spectrometer
(CIRS) collected the first in a series of long integrations of Saturn for
temperature data. The ISS continued with some standard searches for
satellites embedded in the outer part of the rings and outside the main
rings.
On Saturday, May 15th, the first Radio Science Subsystem (RSS) activity
during tour took place. This consisted of a 4-hour long Ultra Stable
Oscillator (USO) characterization, and was also an opportunity to continue
with the Ka-band Translator recovery attempts.
In the last week, 684 ISS images arrived and were distributed along with 77
Visual and Infrared Mapping Spectrometer (VIMS) cubes. The total number of
ISS images acquired since the start of Approach Science is now 6655, and the
number of VIMS cubes is 843.
In support of the Phoebe encounter, the flight team is holding an Operations
Readiness Test (ORT) for the Phoebe Live Update Process. This week an ORT
walk-through was held along with a Live Update ORT Go/No-Go meeting, and a
Phoebe ORT Command approval meeting. Once complete, the files generated
during this test will be run through the Integrated Test Laboratory for
validation.
Sequence development of S02 continued this week with release for review of
the S02 Preliminary Sequence Integration and Validation 2 (PSIV) stripped
subsequence products. Ten sequence change requests (SCR) were dispositioned
at the S02 PSIV SCR approval meeting. A kick-off meeting was held for the
S03 Science and Sequence Update Process.
The Science Operations Plan (SOP) Implementation process for tour sequences
S31 and S32 began this week. Sequences S27 and S28 wrapped up, and S29 and
S30 were merged for official port #1 and are currently being reviewed.
An updated Cassini reference trajectory was released on 13 May 2004. The new
trajectory results from improvements in satellite ephemeris knowledge, and
enables the navigation team to maintain key science objectives while
controlling propellant expenditure within acceptable limits.
SOI readiness reviews this week included a presentation to the Tom Young
committee and an internal Project review. Both reviews resulted in some
actions being accepted, but the consensus of both was that the Project is
well postured for the upcoming SOI.
Members of the flight team traveled to the DSN complex at Goldstone,
California, to perform an Emergency Control Center (ECC) demonstration.
These demos occur periodically to confirm that emergency command capability
is still active and available should the need arise. Unfortunately, a
reoccurrence of a 2-way acquisition failure at DSS-25 invalidated the demo.
The team is currently looking at options for rescheduling the test.
A new version of the Multi-Mission Image Processing Laboratory software set
was accepted for operations at a Delivery Review. Four approved additions
were made to enhance robustness and eliminate some uplink workarounds.
Additional reviews were held for Spacecraft Operations Office tools
Telemetry Input Gap Analyzer and Reporter V1.0, Kinematic Prediction Tool
10.3.5, and IVP 10.3.3.
Approximately 40,000 guests visited JPL and the Cassini display last weekend
for the laboratory’s annual open house. The Cassini display included a
half-scale model of the spacecraft, and screened the planetarium show “Ring
World.” Members from the flight team volunteered time at the different
Cassini exhibits throughout the weekend.
This week’s image is a single filter narrow angle camera view of Titan.
This and previous images can be accessed at:
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.
