Cassini Significant Event Report

For Week Ending 06/30/99

Due to observance of the 4th of July Holiday, this report covers the five
days from June 25 through June 29th. Next week's report will pick up the
two days not covered here.


Spacecraft Status:


The most recent spacecraft status is from the DSN tracking pass on Tuesday,
06/29, over the Canberra tracking station. The Cassini spacecraft is in an
excellent state of health and is operating normally. On June 24th, Cassini
completed a successful Venus flyby. Closest Approach occurred on June 24,
at 20:29:55 UTC at an altitude of 602.6 kilometers above the surface of Venus.
This is only two seconds earlier and four kilometers higher than the flyby
trajectory that was targeted by the last pre-Venus TCM 37 days earlier on
May 18, 1999. 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)


On Friday, 06/25, AACS Monitor Threshold Values were set for the post Venus
period.


On Saturday, 06/26, High Water Marks were cleared and the Venus 2 Playback
Mini-Sequence began execution. Playbacks are scheduled once a day through
Saturday, July 3rd. Following today's playback the Solid State Recorder
(SSR-B) record and playback pointers were reset.


On Sunday, 06/27, Monday, 06/28, and Tuesday, 06/29, Venus 2 playbacks
occurred.


On Tuesday, 06/ 29, Cassini passed perihelion, the closest point to the
Sun on this segment of the trajectory. Perihelion is at 0.7166AU
(Astronomical Units).

Upcoming events:


Venus 2 data playbacks will continue at one pass per day from 06/30
through 07/03. SSR Pointers are reset on 06/30, the CDA instrument is
stowed and AACS parameters are updated in preparation for TCM-9 on 07/01,
SSR pointers are reset on 07/02, AACS Monitor Threshold Values are reset
on 07/03, the TCM-9 Mini-Sequence is uplinked to the Spacecraft and begins
execution on 07/05, High Water Marks are cleared and TCM-9 is performed on
07/06, and the Cruise 15 Background Sequence is uplinked to the Spacecraft,
Flight Software Partition Maintenance is performed, and SSR Pointers are
reset on 07/07.



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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Technology


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Administration


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Telephone (818) 354-5011





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