Cassini Significant Event Report

For Week Ending 01/15/99


Spacecraft Status:


The most recent spacecraft status is from the DSN tracking pass on
Thursday, 01/14, over the Canberra tracking station. The Cassini
spacecraft is in an excellent state of health and is operating nominally. The speed of the spacecraft can be viewed on the "Where is Cassini Now?" web page (http://saturn.jpl.nasa.gov/operations/present-position.cfm)


Spacecraft Activity Summary:


Instrument Checkout (ICO) has been the primary activity over the past week
with the following activities executed:


On Thursday, 01/07, UVIS Checkout, CAPS/MIMI Solar Wind Experiment and
DFPW Roll, and RSS USO TEST 2 were all performed successfully.


On Friday, 01/08, CIRS Checkout and the CAPS/RPWS Interference Test both
performed successfully.


On Saturday, 01/09, ISS Checkout, VIMS checkout, Start of Quiet Test, and
INMS Pressure Test were performed. Some parts of the ISS and VIMS
checkouts were not as expected and analysis is underway to understand
this.


On Sunday, 01/10 Completion of Quiet Test and S&ER 3 Test were performed.


On Monday, 01/11 RSS Test E was performed. Not all objectives of this test
were completed, so it is planned to be repeated during the previously
defined contingency window on DOY 020.


At approximately 23:00 UTC System Fault Protection placed the spacecraft
in a safe state. "Safing" executed exactly as designed, flawlessly placing
the spacecraft in the correct High Gain to sun attitude, 40 bps downlink
telemetry, instruments off and replacement heaters on. Telemetry played
back from the SSR on Tuesday night indicated that the safing resulted from
a small variation in information about the spacecraft's orientation (i.e.,
attitude), that occurred as the spacecraft was doing a slow roll to keep
the sun on the proper side of the spacecraft as it was going through
opposition with Earth.


On Tuesday, 01/12 through Thursday, 01/14, flight controllers developed
plans to return to normal operations. Concurrently Science and Uplink
Office personnel prioritized the remaining activities to be executed in
the remaining ICO time.


Upcoming events:


The events planned for the next reporting period consist of reactivating
the C11 sequence, continuation of ICO activities, and uplink of the C12
sequence.



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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