From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Galileo Update - 10/09/92
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.3-4   
Keywords:  Galileo, JPL
Reply-To: baalke@kelvin.jpl.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Sat, 10 Oct 1992 04:31:49 GMT

Forwarded from Neal Ausman, Galileo Mission Director

                                   GALILEO
                         MISSION DIRECTOR STATUS REPORT
                                 POST-LAUNCH
                            October 2 - 8, 1992

SPACECRAFT

1.  During the period of October 3 through October 4, a navigation cycle was
performed.  This navigation cycle provided near-continuous acquisition of
two-way doppler and ranging data during four consecutive passes of the
spacecraft over DSS-63 (Madrid 70 meter antenna).  This data will improve
orbit determination in support of the TCM-15 (Trajectory Correction Maneuver
#15) scheduled for October 9.

2.  On October 5, a NO-OP command was sent to reset the command loss timer
to 264 hours, its planned value for this mission phase.

3.  On October 5, a routine sun vector update was performed.  This sun vector
is valid through October 27.

4.  On October 5, an Ultra-Stable Oscillator (USO) test was performed to
verify the health status of the USO and collect gravitational red shift
experiment data; long term trend analysis is continuing.

5.  On October 6, real-time commands were sent to temporarily configure the
spacecraft telemetry rate to 1200 bps, which has not been sustainable since
June 1991.  On October 7, the spacecraft was configured to 40 bps uncoded
telemetry and then back to 1200 bps on October 8.

6.  On October 6, a periodic RPM (Retro-Propulsion Module) 10-Newton thruster
maintenance activity was performed; 10 of the 12 thrusters were "flushed"
during the activity.  The P-thrusters were not flushed because they were used
to perform science turn (SITURN) activities on the same day.  Spacecraft
performance throughout the activity was normal.

7.  On October 7, the spacecraft performed a 14.5 degree SITURN.  The purpose
of the SITURN was to maintain the spacecraft within plus or minus 13 degrees
of the sun while at the current solar distance.

8.  On October 7, the Earth vector and Earth stars were updated to the
spacecraft's present attitude.  This change implements the attitude
maintenance strategy required in the case of an AACS (Attitude and
Articulation Control Subsystem) POR (Power On Reset).  If a fault occurs
which terminates the currently executing sequence, the spacecraft will
maintain its current attitude.

9.  On October 7, cruise science Memory Readouts (MROs) were performed for
the Extreme Ultraviolet Spectrometer (EUV), Dust Detector (DDS), and
Magnetometer (MAG) instruments.  Preliminary analysis indicates the data
was received properly.

10. On October 8, spacecraft telemetry maps were updated for the 1200 bps
capability.

11. On October 8, the Trajectory Correction Maneuver (TCM-15) memory load was
uplinked to the spacecraft.  During the initial attempt, one of the eight
TCM-15 messages was rejected by the spacecraft.  The entire High Level Module
(HLM) sequencing memory was readout, verified and the rejected message
retransmitted and verified via memory readout.  This commanding incident is
under investigation.

12. The AC/DC bus imbalance measurements exhibited some change.  The AC
measurement has ranged from 12DN to 16DN and now reads 16 DN (3.7 volts).
The DC measurement has ranged from 116 DN (13.5 volts) to 135 DN (15.8 volts)
and now reads 126 DN (14.7 volts).  These measurement variations are
consistent with the model developed by the AC/DC special anomaly team.

13. The Spacecraft status as of October 8, 1992, is as follows:

       a)  System Power Margin -  69 watts
       b)  Spin Configuration - Dual-Spin
       c)  Spin Rate/Sensor - 3.15rpm/Star Scanner
       d)  Spacecraft Attitude is approximately 11 degrees
           off-sun (leading) and 16 degrees off-earth (lagging)
       e)  Downlink telemetry rate/antenna-1200 bps (coded)/LGA-1
       f)  General Thermal Control - all temperatures within
           acceptable range
       g)  RPM Tank Pressures - all within acceptable range
       h)  Orbiter Science- UVS, EUV, DDS, MAG, EPD, and HIC are
           powered on
       i)  Probe/RRH - powered off, temperatures within
           acceptable range
       j)  CMD Loss Timer Setting - 264 hours
           Time To Initiation - 263 hours


UPLINK GENERATION/COMMAND REVIEW AND APPROVAL:

1.  The Trajectory Correction Maneuver (TCM-15) design package was approved
by the Project on October 2, 1992.  Additionally, the TCM-15 maneuver was
approved for transmission by the Project on October 7, 1992.  TCM-15 is a one
portion maneuver scheduled to execute on October 9 consisting of one axial
segment and one lateral segment.  The estimated total delta velocity for
TCM-15 is .716 m/s.

2.  The EE-12 (Earth-Earth 12) Final Cruise Plan was approved by the Project
on October 5, 1992.  This sequence covers spacecraft activities from
January 20, 1993 to April 12, 1993.

3.  The Dual Drive Actuator (DDA) pulse mini-sequence No. 4 memory load was
approved for transmission by the Project on October 8.  This mini-sequence
covers spacecraft activities associated with the DDA 10-pulse hammer test
from October 12 to October 15.


TRAJECTORY

     As of noon Thursday, October 8, 1992, the Galileo Spacecraft trajectory
status was as follows:

	Distance from Earth         37,027,900 miles (.40 AU)
	Distance from Sun           125,287,800 miles (1.35 AU)
	Heliocentric Speed           61,600 miles per hour
	Distance from Jupiter        618,941,500 miles
	Round Trip Light Time        6 minutes, 44 seconds


SPECIAL TOPIC

1.  As of October 8, 1992, a total of 8237 real-time commands have been
transmitted to Galileo since Launch.  Of these, 3288  were pre-planned in the
sequence design and 4949 were not. In the past week, 6 real time commands were
transmitted and pre-planned in the sequence design.  In addition, 5677
mini-sequence commands have been transmitted since March 1991; 3519 were
pre-planned and 2158 were not.  In the past week, no mini-sequence commands
were transmitted.  Major command activities this week included commands to
reset the command loss timer, configure the spacecraft telemetry rate to
1200 bps, and uplink the TCM-15 memory load.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | baalke@kelvin.jpl.nasa.gov
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Einstein's brain is stored
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | in a mason jar in a lab
|_____|/  |_|/       |_____|/                     | in Wichita, Kansas.

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