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Forwarded from Peter Beech, Ulysses Mission Operations Manager

SUBJECT:  ULYSSES MISSION OPERATIONS REPORT No. 125

PERIOD:   12th January to 18th January 1993

1.   MISSION OPERATIONS

     Experiment  reconfigurations  have  been  carried   out   as
     required.

     A HUS (Solar X-ray instrument) calibration test was conducted on
     12th January.

     A HED (Magnetic Field instrument) calibration was conducted on
     13th January.

     A  KEP  EPAC  (Energetic Particles instrument) in-flight calibration
     was  conducted  on  18th January.

     Routine Earth pointing manoeuvres were performed on 14th and
     17th January.

     An  average of 92.06 % data recovery was achieved during the
     reporting period.

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

     1024 bps 49.63 %
      512 bps 42.37 %

     The  lower  than  normal data recovery  for  this  reporting
     period  was  due to a maser low noise amplifier  failure  at
     Goldstone which caused a complete loss of a scheduled  pass.
     The  outage was minimised by support being provided from the
     Canberra  station.  A total of 10 hours of  real  time  data
     were lost.

2.   SPACECRAFT STATUS

     POWER

     Nominal.
     Estimated S/C power consumption 257 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.   Ranging  from  34  meter  ground  stations  is
     performed when the spacecraft is configured for bit rates of
     1024  bps  or  less.  Ranging passes from  70  meter  ground
     stations are also being taken periodically.

     Received downlink level -138 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 -123 dBm.

     DATA HANDLING

     Nominal.

     THERMAL

     Nominal.

3.   FLIGHT DYNAMICS

     Solar Aspect   The angle reduced from 9.85 on
     Angle (deg.)   12th January to 9.24 on 18th January.

     Sun-Probe-Earth  The angle reduced from 9.81 on
     Angle (deg.)     12th January to 9.12 on 18th January.

     Spin Rate               4.980 rpm.

4.   ORBITAL DATA

     Data taken at 13:00 PDT on 18th January.
     Distance from Earth                657,698,384 km.
     Velocity relative to the Earth         124,022 km/hr.
     Velocity relative to the Sun            34,220 km/hr.
     Ecliptic latitude                         16.7 deg/south

5.   PLANNED OPERATIONS

     Routine  data  gathering operations will  continue  together
     with experiment reconfigurations as required.
     On  19th  January  a KEP GAS (Interstellar Neutral Gas instrument)
     monthly health  check  will  be carried out.

     On  25th  January a KEP EPAC in-flight calibration  will  be
     carried out.

     Earth pointing manoeuvres will be performed on 20th and 23rd
     January.

     Periods  of 2048 bps at low antenna elevations will continue
     to  be  avoided to improve the signal to noise ratio.   This
     will  slightly  reduce the percentage of 1024 bps  real-time
     data received.

6.   GROUND SEGMENT

     The  ground segment performed nominally during the reporting
     period  with  the exception of the Goldstone  maser  problem
     referred to above.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | baalke@kelvin.jpl.nasa.gov
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Every once in a while,
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | try pushing your luck.
|_____|/  |_|/       |_____|/                     |