From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Ulysses Update - 08/18/92
Followup-To: sci.space
News-Software: VAX/VMS VNEWS 1.3-4   
Keywords:  Ulysses, JPL, ESA
Reply-To: baalke@kelvin.jpl.nasa.gov
Organization: Jet Propulsion Laboratory
Date: Thu, 20 Aug 1992 01:21:08 GMT

Forwarded from Peter Beech, Ulysses Mission Operations Manager

SUBJECT:  ULYSSES MISSION OPERATIONS REPORT No. 104

PERIOD: 11th to 17th August 1992

     Correction to Mission Operations Report No. 103

     The percentage of data acquired as a function of bit rate should
     have read as follows.

     1024 bps 41.19%
      512 bps 39.65%

1.   MISSION OPERATIONS

     Experiment  reconfigurations  have  been  carried  out  as
     required.

     Routine Earth pointing manoeuvres were performed on 13th  and
     16th August.

     The KEP GAS (Energetic Particles and Interstellar Neutral Gas
     instrument) Health check that was not carried out last week
     as  a  result  of  ground  segment  problems  was  performed
     successfully on 11th August.

     An  average of 95.9 % data recovery was achieved during  the
     reporting period.

     The percentage of data acquired as a function of bit rate is
     as follows:

     1024 bps 53.6 %
      512 bps 42.3 %

     A reduction in the number of ranging passes continued during
     the reporting period in order to improve the poor signal  to
     noise  ratio  encountered at the present  large  spacecraft-
     Earth distances.

2.   SPACECRAFT STATUS

     POWER

     Nominal.
     Estimated S/C power consumption 260 watts.
     AOCS

     Nominal.

     TTC

     The  spacecraft is currently configured with receiver  2  as
     the  prime  unit  fed  via the high gain  antenna  and  with
     receiver 1 as backup fed through the low gain antenna  (LGA-
     F). The downlink is provided through EPC2/TWTA2.

     The  34  meter  ground stations are in use  to  support  TTC
     operations, with at least one 70m station pass per  week  to
     support ranging.

     Received downlink level -147 dBm.(34 meter) X-band.

     (Variations of up to 10 db. can be expected as a  result  of
     station  antenna  in  use,  local  weather  conditions,  and
     spacecraft antenna off-pointing).

     Received uplink level -124 dBm.

     DATA HANDLING

     The  anomaly on CTU2 reported in previous Operations Reports
     is still under investigation.

     THERMAL

     Nominal.

3.   FLIGHT DYNAMICS

     Solar Aspect   The angle decreased from 3.36 on
     Angle (deg.)   11th August to 2.65 on 17th August.

     Sun-Probe-Earth  The angle decreased from 3.56 on
     Angle (deg.)     11th August to 2.78 on 17th August.

     Spin Rate               4.982 rpm.

4.   ORBITAL DATA

     Data taken at 13:00 PDT on 17th August.
     Distance from Earth                937,085,189 km.
     Velocity relative to the Earth          112,459 km/hr.
     Velocity relative to the Sun              30,799 km/hr.
     Ecliptic  latitude                         8.4 deg/south

5.   PLANNED OPERATIONS

     Routine  data  gathering operations will  continue  together
     with experiment reconfigurations as required.

     Earth pointing manoeuvres will be performed on 19th and  and
     23rd August.

     Periods  of  2048  bps  at low antenna  elevations  will  be
     avoided  to improve the signal to noise ratio in the  coming
     months.   This will slightly reduce the percentage  of  1024
     bps real-time data received.  During this period, 70m passes
     will   also  be  scheduled  to  perform  ranging  at   large
     spacecraft-Earth distances while maintaining the desired bit
     rates.

6.   GROUND SEGMENT

      The ground segment performed nominally during the reporting
      period.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | baalke@kelvin.jpl.nasa.gov
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Optimists live longer
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