From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Galileo Update - 07/31/92
Keywords: Galileo, JPL
Date: 1 Aug 92 00:34:23 GMT
Reply-To: baalke@kelvin.jpl.nasa.gov
Followup-To: sci.space
Organization: Jet Propulsion Laboratory
News-Software: VAX/VMS VNEWS 1.3-4

Forwarded from Neal Ausman, Galileo Mission Director

                                  GALILEO
                       MISSION DIRECTOR STATUS REPORT
                                POST-LAUNCH
                            July 24 - 30, 1992


SPACECRAFT

1.  On July 24, as part of the DDA (Dual Device Actuator) pulse/LGA-2 (Low
Gain Antenna #2) stow activity, real-time commands were sent to checkout the
star scanner.  This activity was performed as a precaution to protect the star
scanner from "seeing" bright particles which could release if an HGA (High
Gain Antenna) rib released.  Additionally, real-time commands were sent to
open the Star Scanner (SS) shutter and to reacquire celestial reference.
Scan Type 6 was selected which allowed the collection of precise wobble data.
Analysis indicates the wobble estimate to be approximate .7 milliradians
following the open loop wobble compensation on July 23.  Also, real-time
commands were sent to reconfigure the System Fault Protection (SFP) AACS-INIT
(Attitude and Articulation Control Subsystem) pointing slot from the Sun to
the Earth after the DDA pulse/LGA-2 stow activities.  This change will allow
the spacecraft to lock up on the star set in the Earth slot if an AACS Power
on Reset (POR) occurs.

2.  On July 27, a NO-OP command was sent to reset the command loss timer to
264 hours, its planned value for this mission phase.

3.  During the week, the DC bus imbalance reading has continued to change
significantly.  The DC measurement has ranged from 105DN (12.2 volts) to
148DN (17.4 volts) and now reads 122DN (14.2 volts).  This measurement
variation is consistent with the model developed by the AC/DC special anomaly
team.  The AC measurement has remained relatively unchanged and reads
3.1 volts.

4.  The Spacecraft status as of July 30, 1992, is as follows:

       a)  System Power Margin -  51 watts
       b)  Spin Configuration - Dual-Spin
       c)  Spin Rate/Sensor - 3.16 rpm/Star Scanner
       d)  Spacecraft Attitude is approximately 5 degrees
           off-sun (leading)
       e)  Downlink telemetry rate/antenna-40 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 - 184 hours



GDS (Ground Data Systems):

1.  The DSN (Deep Space Network) placed the new Telemetry Processor Assembly
(TPA) software version OP-D 4.01 into SOAK test at all complexes on 28 July.
The project participated in a successful Multimission Verification Test (MVT)
for this software on May 27.


 TRAJECTORY

     As of noon Thursday, July 30, 1992, the Galileo Spacecraft trajectory
 status was as follows:

        Distance from Earth         116,127,000 miles (1.25 AU)
        Distance from Sun           163,651,000 miles (1.76 AU)
     	Heliocentric Speed          47,400 miles per hour
     	Distance from Jupiter       667,782,000 miles
     	Round Trip Light Time       20 minutes, 56 seconds

SPECIAL TOPIC

1.  As of July 30, 1992, a total of 8094 real-time commands have been
transmitted to Galileo since Launch.  Of these, 3222  were pre-planned in the
sequence design and 4872 were not.  In the past week, 32 real time commands
were transmitted; all were pre-planned in the sequence design.  In addition,
5453 mini-sequence commands have been transmitted since March 1991; 3201 were
pre-planned and 2252 were not. In the past week, no mini-sequence commands
were transmitted.  Major command activities this week included commands to
checkout the star scanner, open the star scanner shutter and reacquire
celestial reference, select scan Type 6, reconfigure the system fault
protection, and reset the command loss timer.

2.  The High Gain Antenna (HGA) DDA pulse/LGA-2 stow activities were scheduled
from July 21 to July 24, 1992.  The warming turn to a 31 degree off-sun
attitude along with the first DDA two second motor turn on was performed on
July 21.  The spacecraft remained at the warming attitude for approximately
24 hours.  The second DDA motor turn on was performed on July 22 just prior to
the spacecraft turning back to a 5 degree off-sun attitude.  Sun gate data was
collected after the sun acquisition completed.  The LGA-2 motors were turned
on for 16 seconds on July 23 and the LGA-2 antenna was successfully stowed.
The star scanner checkout, along with collection of sun gate and wobble data
was completed during the July 23-24 time period.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | baalke@kelvin.jpl.nasa.gov
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Most of the things you 
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | worry about will never
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