Cassini Significant Event Report

For Week Ending 05/19/00

The most recent spacecraft telemetry data was acquired from the Canberra
tracking station on Monday, 5/15. The Cassini spacecraft is in an excellent
state of health and is operating normally with the Cosmic Dust Analyzer
(CDA), Magnetometer (MAG), and Radio & Plasma Wave Spectrometer (RPWS)
instruments on and taking data at this time. The speed of the spacecraft can be viewed on the "Where is Cassini Now?" web page.


The spacecraft has passed through superior conjunction. Superior
conjunction occurs whenever the Sun and the Cassini spacecraft have their
least apparent angular separation as viewed from Earth, and the Sun is
between the spacecraft and Earth.


The primary activity during this time was an uplink characterization test.
A total of 100 "no operation" commands were sent to the spacecraft at both
250 bits per second (bps) and 500 bps to enable characterization of the
total radio link and radiometric performance in the presence of noise from
the Sun. This assists Cassini personnel in determining the minimum angle
between the sun and spacecraft where the spacecraft can be safely
commanded.


As noted on May 12, Cassini provided radio tracking information for the
Solar Probe Mission. As currently planned, Solar Probe will launch in
November 2003, and arrive at perihelion in July 2007. Solar Probe will
fly through the Sun's corona. This mission is currently in development and
requested Cassini data from superior conjunction to assist them in better
understanding the effects on downlink as a spacecraft gets closer to the
sun. Development personnel will be examining Cassini signal strengths, and
success rate of commanding, and will use this information to develop Solar
Probe mission design.


Cassini Outreach made a presentation at Cal Poly Pomona to the American
Institute of Aeronautics and Astronautics, and participated in NASA's
exhibit at the annual convention of the American Association of Retired
Persons, Orlando, Florida.


As a variation on outreach activities, the Cassini Virtual Singers had
their first-ever public gig at an Alhambra Rotary Club meeting. Besides
singing selected Cassini/Saturn songs, there were short discussions of
various aspects of the Cassini mission to Saturn.


VIMS personnel have successfully completed a test with the Integration Test
Laboratory (ITL) in preparation for the ICO-2 flight software load and
test. The test ran flawlessly with housekeeping reporting expected status.


A Delivery Coordination Meeting (DCM) was held for ISS Version 4.4 Ground
Software. This delivery allows the ISS EGSE workstation to retrieve
telemetry from a wider range of operations machines.


The functional requirements document for the encounter version of the
Navigation Software System has been released. These requirements will
control the augmentation to the Navigation System necessary for orbital
operations.


The project has agreed on Enceladus flyby option E3 as the baseline for
now. A review has been scheduled for November 2006, to reconsider the E3a
option. Enceladus is generally acknowledged to potentially have a special
relationship with the E ring of Saturn and is of interest to multiple
discipline areas.



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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