From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Galileo Update - 11/13/92
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, 14 Nov 1992 01:00:32 GMT

Forwarded from Neal Ausman, Galileo Mission Director

                                  GALILEO
                      MISSION DIRECTOR STATUS REPORT
                                POST-LAUNCH
                          November 6 - 12, 1992

SPACECRAFT

1.  On November 6, real-time commands were sent to turn the Ultraviolet
Spectrometer (UVS) instrument off in response to the anomalous state of the
instrument observed when the telemetry rate was configured to Low Rate Science
(LRS).  Possible causes of this anomaly include the TCC-244 read disturb
problem.  The UVS team is continuing its investigation of the anomaly and the
implementation of a recovery plan.

2.  On November 6, delta Differenced One-Way Range (DOR) passes were performed
over DSS-14/63 (Goldstone/Madrid) and DSS-14/43 (Goldstone/Canberra).  Initial
results indicate both of the delta DOR passes were successfully performed.

3.  On November 6, a NO-OP command was sent to reset the command loss timer
for both strings of the Command and Data Subsystem (CDS) computer to 264 hours,
its planned value for this mission phase.

4.  On November 6, the Plasma Wave (PWS) and Plasma Detector (PLS) instruments
were turned on.  Spacecraft telemetry indicates the PWS search coil is
operating normally, even after the severe cold temperature environment it went
through during the High Gain Antenna (HGA) warming turn/cooling turn campaign.
Additionally, the Energetic Particle Detector (EPD) memory was loaded and
checked by memory readouts, along with configuration changes to the
magnetometer sensor.

5.  On November 7, the radio science gravity wave experiment system test began
and will continue through November 13.  This system test is in preparation for
a joint experiment with Ulysses and Mars Observer in March/April 1993.

6.  On November 8, a delta Differenced One-Way Range (DOR) pass was performed
over DSS-14/63 and preliminary indications are that it was successfully
performed.

7.  On November 9, a NO-OP command was sent to reset the command loss timer to
264 hours, its planned value for this mission phase.

8.  On November 11, a routine sun vector update was performed.  This sun
vector is valid through November 25.

9.  On November 12, the Energetic Particle Detector (EPD) motor was turned on
and the instrument stepped to Sector 0 which is the predicted least
contamination position in preparation for the execution of TCM-16 (Trajectory
Correction Maneuver #16).

10. On November 12, the Trajectory Correction Maneuver (TCM-16) memory load
was uplinked to the spacecraft without incident.

11. On November 12, Delayed Action Commands (DACs) were sent to turn the
Photometric Calibration Target (PCT) off/on and off again for the purpose of
Retro-Propulsion Module (RPM) tank pressure/temperature management.

12. The AC/DC bus imbalance measurements exhibited some change.  The AC
measurement has ranged from 16DN to 17DN and now reads 17 DN (3.9 volts).
The DC measurement has ranged from 131 DN (15.3 volts) to 140 DN (16.4 volts)
and now reads 139 DN (16.3 volts).These measurement variations are consistent
with the model developed by the AC/DC special anomaly team.

13. The Spacecraft status as of November 12, 1992, is as follows:

      a)  System Power Margin -  72 watts
      b)  Spin Configuration - Dual-Spin
      c)  Spin Rate/Sensor - 3.15 rpm/Star Scanner
      d)  Spacecraft Attitude is approximately 7 degree
          off-sun (lagging) and 8 degrees off-earth (lagging)
      e)  Downlink telemetry rate/antenna-7.68kbps (coded)/LGA-1
      f)  General Thermal Control - all temperatures within
          acceptable range
      g)  RPM Tank Pressures - all within acceptable range
      h)  Orbiter Science- PWS, PLS, EPD, MAG, HIC and DDS are
          powered on
      i)  Probe/RRH - powered off, temperatures within
          acceptable range
      j)  CMD Loss Timer Setting - 186 hours
          Time To Initiation - 260 hours


UPLINK GENERATION/COMMAND REVIEW AND APPROVAL:

1.  The Trajectory Correction Maneuver (TCM-16) design package was approved
by the Project on November 9, 1992.  Also, the TCM-16 maneuver was approved
for transmission by the Project on November 12, 1992.  TCM-16 is a one
portion maneuver scheduled to execute on November 13 consisting of one lateral
segment.  The estimated total delta velocity for TCM-16 is .89 m/s.


GDS (Ground Data Systems):

1.  A Telemetry Test was conducted with SPC-60 (Madrid Signal Processing
Center) on Tuesday, November 10 to isolate intermittent communication related
data losses being observed during flight support and to demonstrate performance
in the configuration to be used for Earth 2 high rate support.   A
configuration was achieved which provided three hours of error-free
performance at the 28.8 kbps telemetry rate to be used for the Probe MST
(MCCC Telemetry Subsystem) and AFST.  Prior to that period, there were data
loss problems and it is not clear what action at the station corrected the
problems (analysis of all logs and data is in progress).  In addition, data
lock could not be maintained with the Type B TPA (Telemetry Processing
Assembly) at rates above 80.64 kbps.  This same problem has been observed at
the other SPCs with Type B telemetry strings.  This may reflect a performance
degradation introduced with the TPA B Op D software put on-line several months
ago and may be corrected by disabling recording of data at the TPA.  Type A
TPAs do not exhibit this problem and will be prime for Earth 2 support.
Additional testing is being planned with SPC-60 early next week to demonstrate
the configurations that will be used for high rate Earth 2 flight support
including 28.8 kbps used for the Probe MST/AFST and 134.4 kbps used for high
rate science.

TRAJECTORY

     As of noon Thursday, November 12, 1992, the Galileo Spacecraft trajectory
status was as follows:

	Distance from Earth         20,040,300 km (.13 AU)
	Distance from Sun           167,289,500 km (1.12 AU)
	Heliocentric Speed          115,500 km per hour
	Distance from Jupiter       926,895,300 km
	Round Trip Light Time       2 minutes, 18 seconds


SPECIAL TOPIC

1.  As of November 12, 1992, a total of 8649 real-time commands have been
transmitted to Galileo since Launch.  Of these, 3660  were initiated in the
sequence design process and 4989 initiated in the real-time command process.
In the past week, 13 real time commands were transmitted: 1 was initiated in
the sequence design process and 12 initiated in the real time command process.
In addition, 5911 mini-sequence commands have been transmitted since
March 1991; 3753 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 turn the UVS instrument off, reset the command loss timer,
uplink TCM-16 memory load, and reconfigure the PCT heater.
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    /_ /|  /____/ \  /_ /|     Ron Baalke         | baalke@kelvin.jpl.nasa.gov
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