Cassini Significant Event Report
For Week Ending 06/26/98
The most recent Spacecraft status is from the DSN tracking pass on Wednesday, 06/24, over Goldstone.
The Cassini spacecraft is in an excellent state of health and is executing the C8 sequence 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)
Inertial attitude control is being maintained using the spacecraft's hydrazine thrusters (RCS system). The
spacecraft continues to fly in a High Gain Antenna-to-Sun attitude. It will maintain the HGA-to-Sun attitude,
except for planned trajectory correction maneuvers, for the first 14 months of flight.
Spacecraft Activity Summary:
On Wednesday, 06/24, four activities were executed on board the spacecraft. First, the Solid State Recorder
(SSR) record and playback pointers were reset, according to plan. This housekeeping activity, done
approximately weekly, maximizes the amount of time that recorded engineering data is available for playback
to the ground should an anomaly occur on the spacecraft.
Next, the antenna selected for communication with the spacecraft was changed from Low Gain Antenna
(LGA) 2 to LGA 1, according to plan.
Following this activity, maintenance was performed on the SSR Flight Software Partitions. This activity,
performed approximately every 2 weeks, repairs any SSR double bit errors (DBEs) which have occurred in
the code-containing portions of the Flight Software partitions during the preceding period.
Finally, a housekeeping activity was performed which reads out a set of AACS Attitude Estimator (ATE)
measurements not available in regular engineering telemetry. This ATE telemetry allows ground controllers to
track the normal functioning of the attitude estimator software on the spacecraft. The readout is scheduled
approximately every 2-4 weeks, over an available DSN telemetry pass.
Activities scheduled for the week of 06/26 - 07/02 include: Periodic Engineering Maintenance 06/29, and
SSR Pointer Reset, 07/01.
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.