Cassini Significant Events -- 09/29/05 - 10/05/05

October 7, 2005

(Source: NASA/JPL)


The most recent spacecraft telemetry was acquired Wednesday, October 5, from
the Canberra tracking stations. 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 .


Thursday, September 29 (DOY 272):

In last week's report it was mentioned that the project had decided to go
after the approximately 88Mb of data lost during the Hyperion DSS-14 70m
playback on DOY 270. After discussions with Spacecraft Operations, Mission
Planning, Science Planning, Program Management, and the sequence leads, the
strategy selected was to move the SSR-B record and playback pointers to
protect the Hyperion data. The necessary files were radiated on DOY 272 to
move these pointers. CDS confirmed via telemetry that the pointers had moved
to the correct positions. The data will be played back during the DOY 277
DSS-14 track, Tuesday, October 4.

A Cassini Design Team meeting was held to review the Team/Office baseline
development plans for the Spring 2006 version D12 Mission Sequence Subsystem
delivery. The purpose of the meeting was to ensure a common understanding
of the capabilities being planned and the rationale behind the priorities
that have been established, to understand the schedule constraints, and to
obtain project management approval of the plan.

It has been decided to cancel the S16 simulation coordination and procedure
review meetings since no activities have been identified that require
simulation in the Integrated Test Laboratory prior to sequence uplink.

Science Planning chaired the S16 Science Allocation Planning meeting today
for the purpose of distributing available sponge bits amongst interested
parties. Sponge bits represent available data volume that is given away to
the teams at this stage in the Science and Sequence Update process. The
sequence leads do not expect any further changes to DSN allocation, so much
of the data volume that was being held as margin is given to the teams for
science. Prior to the meeting, the Science Planning lead determines how much
extra data volume is available and teams request the data volume that they
need. If more data volume is requested than is available, negotiations are
made during the meeting. In this instance 18.5 Gbits of data were available
and there were no conflicts.


Friday, September 30 (DOY 273):

SOST hosted a Dione/Rhea preview meeting. Planned science objectives and
activities were presented.

JPL Media Relations has released an image advisory on the recent Tethys and
Hyperion flybys. This was the closest flyby to date of both bodies. Tethys
has a scarred, ancient surface, while Hyperion is a strange, spongy-looking
body with dark-floored craters that speckle its surface. For more
information go to http://saturn.jpl.nasa.gov.


Monday, October 3 (DOY 276):

A Titan Atmospheric Working Group meeting was held today to discuss the
Titan 7 flyby data and implications for future Titan flyby altitudes.

An amazingly clear picture of Hyperion is Astronomy Picture of the Day
today.

The sequence leads began uplink of the Instrument Expanded Block files in
support of the S15 sequence. Five files were sent. S15 will begin execution
on board the spacecraft on Saturday, October 8.


Tuesday, October 4 (DOY 277):

SSR partition B4 has completed playback and it has been confirmed that the
lost RADAR data between 269T06:00:16 and 269T06:21:49 has been replayed. The
RADAR team sent a message to program members announcing that all the missing
Hyperion data, 85 Mbits of science and engineering packets, and 0.02 Mbits
housekeeping, have been received.

Final sequence development for S17 began today with a kick off meeting.
Initial sequence products will be released for review later today.

An encounter strategy meeting was held today for the Dione 1 through Titan 8
flybys. This covers the period from October 11 through October 28, and
includes Orbit Trim Maneuvers 38-40.