Cassini Significant Event Report

For Week Ending 08/29/03

The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Wednesday, August 27. The Cassini spacecraft is in an excellent state of health and is operating normally. Information on the spacecraft's position and speed can be viewed on the "Present Position" web page.

On-board activities this week included regularly scheduled Backup ALF Injection Loader maintenance, and clearing of the ACS high water marks. Instrument activities included a Cassini Plasma Spectrometer flight software checkout, a Composite Infrared Spectrometer remote sensing pallet heater test, a Magnetometer Subsystem SSR library load test, a Probe mute test, and several Radio and Plasma Wave Science High Frequency Receiver calibrations.

August 18 marked the 4-year anniversary of Cassini's Earth flyby. Earth was the third in a four-planet gravity assist trajectory - Venus Venus Earth Jupiter - that has been utilized by the spacecraft to enable it to reach Saturn in July of 2004.

A kick-off meeting was held for the C40 cruise sequence. Stripped spacecraft activity sequence files to be used in this process were released to the teams. C40 is the last sequence in the Cassini Space Science Subphase. The next subphase, Approach Science, contains C42, C43, and C44. These will be followed by the first tour sequences beginning with S1.

Last week's Live Update Verification and Validation (V&V) activity concluded successfully. Products from that exercise are currently being run in Cassini's Integrated Test Laboratory. This facility allows simulation of exact conditions on board the spacecraft, and enables commands to be tested without any operational risk.

Uplink Verification and Validation (V&V) is now concluded. A wrap up review was held covering action items and lessons learned from the Science Operations Plan (SOP) Update, Science and Sequence Update, and Live Update V&V activities.

Products were delivered for official input port #1 for Science Operations Plan implementation of tour sequences S01, S02, S03, and S04. The input files for S01 an S02 are currently being merged and will be delivered to ACS for end-to-end pointing analysis. ACS analysis is complete for files from S03 and S04.

Last week it was incorrectly reported that RPWS had produced a pre-peer review volume of archive data, and a peer review volume of Gravitational Wave Experiment 1 data for Planetary Data System (PDS) review. The correct statement is that RPWS produced a pre-peer review volume of archive data for the PDS review, and the Radio Science Subsystem (RSS) produced a peer review volume of Gravitational Wave Experiment 1 data for PDS review. Apologies to these instrument teams for last week's incorrect report.

As a result of their participation in the recent Saturn Orbit Insertion (SOI) demonstration, the RSS group has submitted a report to the Cassini Program on support of real-time visibility into events that will occur during SOI.

The Navigation Team has released an update to the Cassini Navigation Plan. This version contains the navigation strategy and predictions for approach, SOI, tour, and Huygens probe delivery.

Cassini Outreach gave a presentation on the Cassini mission to 40 educators from Astrocamp.

In early 2005, the European Space Agency's (ESA) Huygens probe will descend through the cloak of gases surrounding Titan, Saturn's largest and most mysterious moon. An Italian-led team of European scientists and engineers has ingeniously tackled the challenges of testing the reliability, behavior, and response of some of the probe's instruments in actual operation -- not simulations.

Scientists gathered at the Italian Space Agency's Trapani balloon-launch facility in Sicily to launch a 500-kilogram gondola carrying the mock-up Huygens space probe. A helium balloon that fully inflated to a diameter of 100 meters at its maximum altitude raised the gondola to a height of 33 kilometers, at which point a release mechanism opened and dropped the probe. The on-board parachute deployed to slow the probe's fall from 40 meters per second to just 4 meters per second. At that speed, the probe floated gently back to Earth, taking about 30 minutes to complete its journey beneath the ten-meter-wide parachute. This parachute was designed to provide a fall speed very close to the one expected at Titan. For more information link to ESA News

Additional information about Cassini-Huygens is online at

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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