From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Galileo Update - 04/09/92
News-Software: VAX/VMS VNEWS 1.3-4   
Keywords:  Galileo, JPL
Reply-To: baalke@kelvin.jpl.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Fri, 10 Apr 1992 06:58:34 GMT

Forwarded from Neal Ausman, Galileo Mission Director

                                 GALILEO
                    MISSION DIRECTOR STATUS REPORT
                               POST-LAUNCH
                           April 3 - 9, 1992

SPACECRAFT

1.  On April 3, the Cooling Turn No. 6 sequence memory load was sent to the
spacecraft.  Additionally, Memory Readout (MRO) commands were sent to verify
the sequence was loaded correctly.  The sequence was loaded on the spacecraft
without incident (see Special Topic No. 2).

2.  On April 3, Delayed Action Commands (DACs) were uplinked to turn off the
NIMS (Near Infrared Mapping Spectrometer) Radiometric Calibration Target
(RCT) heater (24 watt) on April 10 and back on April 13 during the Cooling
Turn No. 6 sequence.  These actions are necessary to maintain required system
power margin.

3.  On April 3, a delta Differenced One-Way Range (DOR) was performed over
DSS-14 (Goldtone 70 meter antenna) and DSS-63 (Madrid 70 meter antenna).
Initial results indicate that the delta DOR was successfully performed.

4.  On April 6, a NO-OP command was sent to reset the command loss timer to
336 hours, its planned value for this mission phase.

5.  On April 6, the Cooling Turn No. 6 sequence memory load went active.  The
pre-cool portion of the sequence started on April 6 and will be completed on
April 13.  During this pre-cool phase the S-band TWTA (Traveling Wave Tube) is
set to low power mode and consequently, as expected, telemetry data has not
been consistently processed since April 7 at approximately 0014 UTC.

6.  The AC/DC bus imbalance measurements remained unchanged.  The DC
measurement reads 18.9 volts.  The AC measurement reads 2.9 volts.

7.  The Spacecraft status as of 1700 PDT April 9, 1992, could not be determined
by real-time telemetry because the spacecraft is in the pre-cool portion of
Cooling Turn No. 6 with the S-band TWTA in the low power mode.  The following
information is taken from previous spacecraft performance and predicts.

        a)  System Power Margin -  26 watts
        b)  Spin Configuration - All-Spin
        c)  Spin Rate/Sensor - 2.89 rpm/Star Scanner
        d)  Spacecraft Attitude is approximately 10 degrees off
            sun (lagging)
        e)  Downlink telemetry rate/antenna-10 bps (coded)/LGA-1
        f)  General Thermal Control - all temperatures within
            acceptable range
        g)  RPM Tank Pressures - all within acceptable range
        h)  Orbiter Science- EPD, UVS, HIC & SSI are powered on
        i)  Probe/RRH - powered off, temperatures within
            acceptable range
        j)  CMD Loss Timer Setting - 336 hours
            Time To Initiation - 259 hours


UPLINK GENERATION/COMMAND REVIEW AND APPROVAL:

1.  The High Gain Antenna (HGA) motor turn-on mini-sequence was approved for
generation by the Project on April 9, 1992.  The HGA motor is scheduled to be
turned on April 29 for a duration of two seconds.


TRAJECTORY

     As of noon Thursday, April 9, 1992, the Galileo Spacecraft trajectory
status was as follows:

        Distance from Earth          260,527,000 miles (2.80 AU)
        Distance from Sun            201,855,000 miles (2.17 AU)
        Heliocentric Speed           36,000 miles per hour
        Distance from Jupiter        692,417,000 miles
        Round Trip Light Time        46 minutes, 44 seconds

SPECIAL TOPICS

1.  As of April 9, 1992, a total of 7689 real-time commands have been
transmitted to Galileo since Launch.  Of these, 2930 have been pre-planned in
the sequence design and 4759 were not.  In the past week, 41 real time command
was transmitted; 33 were pre-planned in the sequence design, 8 were unplanned.
In addition, 3999 mini-sequence commands have been transmitted since March
1991; (1748 were pre-planned and 2251 were not).  In the past week, 432
mini-sequence commands were transmitted.  Major command activities this week
included commands to: uplink and verify the Cooling Turn No. 6 sequence memory
load, turn the NIMS Radiometric Calibration Target (RCT) heater off and on,
and reset the command loss timer.

2.  The Cooling Turn No. 6 activities are scheduled from April 6 to April 17.
The spacecraft bus cool down period started on April 6 and will continue until
April 13.  The cooling turn will be performed on April 13 and the spacecraft
will remain at the cooling attitude for approximately 50 hours.  The spacecraft
return from the cooling attitude is scheduled for April 16.  The sun gate and
wobble ID data collection is scheduled during the April 16-17 time period.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | baalke@kelvin.jpl.nasa.gov
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | People will believe
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | anything if you whisper it.
|_____|/  |_|/       |_____|/                     | 

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