News | August 17, 2000
Significant Event Report for Week Ending 8/18/2000
Cassini Significant Event Report
For Week Ending 08/18/00
The most recent spacecraft telemetry was acquired from the Madrid tracking
station on Wednesday, 08/16. The Cassini spacecraft is in an excellent
state of health and is operating normally. The speed of the spacecraft can be viewed on the "Where is Cassini Now?" web page.
This week's activity onboard the spacecraft continued to center on the
Command & Data Subsystem Flight Software (CDS FSW) Uplink and Checkout. The
prime string has been successfully running the new (Version 7) software for
over a week while the online (backup) string continues to execute the old
(Version 5) software.
The Composite Infrared Spectrometer (CIRS) team has released preliminary
results from the ICO2 quiet test held on July 26. Data indicate no
interference was detected beyond the instrument's own internal
interference. This is a very positive outcome for this test.
In light of Cassini's fast approaching encounter with Jupiter and its
joint observations with Galileo, two presentations on Galilean satellites
were made at the Cassini Design Team Meeting. The first presentation "Icy
Galilean Satellites" covered recent developments in the understanding of
the surface compositions of the icy Galilean satellites---Europa,
Ganymede, and Callisto. Most of the new results have come from the Near
Infrared Mapping Spectrometer (NIMS) instrument on Galileo. Cassini's
Visual and Infrared Mapping Spectrometer (VIMS) instrument has about twice
the spectral resolution as is available on Galileo. Thus, Cassini data
from the flyby of Jupiter will enable a further refinement of the
identification of the observed absorption bands.
"Constraints on Io's Heat Flow" was the topic of the second presentation.
Io is the most volcanically active place known. About the same size and
density as the Moon, Io exceeds the Moon by about four orders of magnitude
in heat production. The amount of heat flowing from Io's interior is a
fundamental constraint for modeling not only the interior of Io but also
the interior of Jupiter, and the tidal evolution of the orbits of the
The Jupiter Science Planning Virtual Team (SPVT) implementation activity
for C23 completed on August 11, and the product was delivered to the SVT
to continue the final part of the sequence development process. This is
the sequence that will be active on the spacecraft during the closest
approach to Jupiter.
In preparation for the Jupiter Readiness Review to be held on August 25,
developers for Jupiter capabilities met to review status and plans for all
outstanding activities for this phase of the mission. Out of 25
development tasks originally scheduled for this phase, 19 are complete and
6 are still outstanding. No problems are anticipated in reaching planned
readiness by the time of the review.
System Engineering coordinated a switch to new Multi-link Point to Point
Protocol between JPL and Goldstone. This new protocol combines the "Big
Pipe" and the "Little Pipe" (High volume flow and backup capability)
providing a significant increase in available bandwidth for operational
Within the Science Opportunity Analyzer program, the need for new
functionality was identified and is being investigated. Specifically,
given a starting attitude, a turn and/or resulting attitude, it is planned
to evaluate geometric constraints. This would allow prompt elimination of
non-viable attitudes, and should speed up the "what-if" process.
Additional information about Cassini-Huygens is online at http://saturn.jpl.nasa.gov.
Cassini will begin orbiting Saturn on July 1, 2004, and release its piggybacked Huygens probe about six months later for descent through the thick atmosphere of the moon Titan. Cassini-Huygens is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Office of Space Science, Washington, D.C.
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