Cassini Significant Event Report
For Week Ending 08/27/04
The most recent spacecraft telemetry was acquired from the Madrid tracking station on Wednesday, August 25. The Cassini spacecraft is in an excellent state of health and is operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" web page located at http://saturn.jpl.nasa.gov/operations/present-position.cfm .
At the beginning of this week, an encounter strategy meeting was held for encounters Titan a, and Titan b. This included Orbit Trim Maneuvers (OTM) 2, 3, 4 (Ta-3), 5, 6, and 7. Immediately following, the OTM-2 maneuver and command approval meetings were held.
On August 23, OTM-2, the periapsis raise maneuver, was successfully completed. The purpose of this maneuver was to raise Cassini's next closest approach distance to Saturn on October 28 by nearly 300,000 kilometers. The maneuver was necessary to keep the spacecraft from passing through the rings and to put Cassini on target for its first close encounter with Saturn's moon Titan on October 26.
A "quick look" of telemetry immediately after the maneuver showed a burn duration of 51 minutes, 8 seconds, giving a delta-V of 392.9 m/s. The maneuver was the third longest engine burn for the Cassini spacecraft and the last planned pressurized burn in the four-year tour. The Saturn obit insertion burn in July was 97 minutes long, and the deep space maneuver in December 1998 was 88 minutes long.
A new, special procedure for obtaining range points for navigation after burn completion was used during this maneuver. The DSN transmitter was left ON while the spacecraft was turned off Earth-point, and ranging disabled. After the spacecraft came back to Earth-point, a Magellan acquisition or MAQ was performed. This was done in order to obtain range points in the DSN pass after the maneuver. The technique worked successfully.
Latch valve 10 was left open for 33 minutes after the burn completed in order to further pressurize the oxidizer and fuel tanks for future maneuvers. The propulsion team indicated the burn was fully pressurized with the regulator performing normally. Tank pressures, latch valve performance, etc, were normal. For more details on this maneuver refer to the Cassini Website, News Release 2004-208 at http://saturn.jpl.nasa.gov/
Science activities this week included optical remote sensing (ORS) scans of Saturn's south pole as well as Ultraviolet Imaging Spectrograph mosaics of Saturn's magnetosphere. Imaging Science Subsystem (ISS) performed mosaics and movies of the rings and Saturn's south pole. Magnetospheric Imaging Instrument (MIMI) imaged the magnetosphere and observed the solar winds and pickup ions while the ORS instruments simultaneously observed Saturn's aurora. Magnetospheric and Plasma Science (MAPS) continued its campaign to study the influence of the solar wind on Saturn's aurora.
A wrap up meeting was held for the Science Operations Plan (SOP) Implementation of tour sequences S33 and S34. The products have been archived and will be available for use in April of 2007 when the S33 Aftermarket process begins.
A kick-off meeting was held for SOP Implementation of S37/S38. Preliminary port #1 is scheduled for September 10.
The official port for SOP Update of S06 occurred this week. The products have been merged and delivered to ACS for end-to-end pointing analysis.
The S04 Preliminary Sequence Integration and Validation-2 (PSIV) merged sequence products were published for teams to review and for ACS to use for Inertial Vector Propagator (IVP) & Kinematic Prediction Tool (KPT) inputs as part of the Science and Sequence Update Process (SSUP). In addition, instrument teams submitted their Instrument Expanded Block Spacecraft Activity Sequence Files. For S05 development, PSIV1 Cycle 1 merged files were placed in the Program file repository for team review, and a Sub-Sequence Generation sequence change request approval meeting was held.
In the last week, 578 ISS images and 130 Visual and Infrared Mapping Spectrometer (VIMS) cubes were acquired and distributed. So far since Approach Science began, 18004 ISS images and 4914 VIMS cubes have been returned.
A delivery review of Multi Mission Image Processing Laboratory software version D32 was conducted this week. No concerns were brought up and the delivery was accepted by all Projects. Instrument Operations personnel will perform certification testing prior to releasing the software for operational use by Cassini in early September.
The final scheduled release of the Cassini Information Management System (CIMS) 3.2 has been installed for operations. The CIMS developers wish the flight team a successful mission!
This week Cassini Outreach and Saturn Observation Campaign members supported the Pasadena Public Library's "Night Under The Stars" event. Sixty kids aged 5- 12 and their parents enjoyed telescopic views after dining on stars, moons and crater dip punch. During the evening the traveling " NASA @ your library" exhibit was displayed featuring one exhibit-stand with six flat-screen computers, and a plasma screen theatre showing NASA programming, in addition to mission models and more. The exhibit opened August 13, runs through September 19, and is open during all library hours.
For the most recent Cassini information, press releases, and images, go to http://saturn.jpl.nasa.gov.