Cassini Significant Event Report
For Week Ending 01/05/98
MSO Significant Events input for week of Friday 12/12 through Sunday 1/4:
Most recent Spacecraft status is from the DSN tracking pass on Thursday morning,
Jan. 1, over Canberra.
The Cassini spacecraft is in an excellent state of health and is operating
nominally. The C5 sequence continues to execute onboard the spacecraft. Early-
cruise spacecraft configuration activities are nearly complete. 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 flying in a High Gain Antenna-
to-Sun attitude. It will maintain the HGA-to-Sun attitude, except for needed
trajectory correction maneuvers, for the first 14 months of flight.
Communication with Earth during early cruise is via one of the spacecraft's two
low-gain antennas; the antenna selected depends on the relative geometry of the
Sun, Earth and spacecraft.
Spacecraft Activity Summary:
The 28-day Magnetospheric Imaging Instrument (MIMI) decontamination activity,
begun on 11/21, continued nominally and ended on planned Dec.
From Friday, 12/12, through Monday, 1/5, there were no changes in spacecraft
On Wednesday, 12/17, Tuesday 12/23, Monday 12/29 and Sunday 1/4, 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.
Also on Wednesday, 12/17, the UVIS-only Periodic Instrument Maintenance (PIM)
was begun. This activity executed according to plan ending 24 hours later on
Thursday, 12/18. Due to the successful puncture of the UVIS membrance in early
November, this Wednesday's activity was the last of the monthly UVIS-only PIMs.
UVIS will continue to participate in the "all-instrument" PIMs which occur every
Upcoming spacecraft events:
Events for the coming week include the uplink of the CG sequence.
Being past the L+30 point in its mission, Cassini no longer requires continuous
DSN coverage. Over the past week Cassini had one DSN track period. In the
coming week, there will be one DSN pass.
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.