From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Ulysses Update - 10/05/92
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, 8 Oct 1992 02:15:55 GMT

Forwarded from Peter Beech, Ulysses Mission Operations Manager

SUBJECT:  ULYSSES MISSION OPERATIONS REPORT No. 111

PERIOD:   29th September to 5th October 1992

1.   MISSION OPERATIONS

     Experiment  reconfigurations  have  been  carried   out   as
     required.

     Routine Earth pointing manoeuvres were performed on 1st  and
     4th October.

     An  average of 96.1 % data recovery was achieved during  the
     reporting period.

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

     1024 bps 44.43 %
      512 bps 51.32 %

     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 259 watts.

     AOCS

     Nominal.

     TTC (Telemetry, Tracking & Control subsystem)

     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 -146 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 -125 dBm.

     DATA HANDLING

     The  anomaly on CTU2 (Central Terminal Unit #2) reported in
     previous Operations Reports is  still  under  investigation.
     However, some  conclusions have   now   been  reached  which
     point  to  an  electrical connection  between two adjacent
     data lines as a  result  of component  failure.  The
     operational impact of this  anomaly is being studied by both
     the Spacecraft Control Team and the instrument teams in the
     event that this CTU would have to be configured for operational
     use.

     THERMAL

     Nominal.

3.   FLIGHT DYNAMICS

     Solar Aspect   The angle increased from 4.54 on
     Angle (deg.)   29th September to 5.33 on 5th October.

     Sun-Probe-Earth  The angle increased from 4.38 on
     Angle (deg.)     29th September to 5.20 on 5th October.

     Spin Rate               4.981 rpm.

4.   ORBITAL DATA

     Data taken at 13:00 PDT on 5th October.
     Distance from Earth                909,328.853 km.
     Velocity relative to the Earth          123,557 km/hr.
     Velocity relative to the Sun              31,712 km/hr.
     Ecliptic latitude                         10.9 deg/south

5.   PLANNED OPERATIONS

     On 6th October Ulysses will achieve two years in orbit.

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

     On 6th October a KEP GAS (Energetic Particles instrument) health
     check will be carried out.

     On 7th October a HED (Magnetic Field instrument) calibration
     will be carried out.

     Earth pointing manoeuvres will be performed on 7th, and 10th
     and 13th  October.

     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  with the exception of some hardware problems at  the
     Goldstone site which gave rise to some small data losses.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | baalke@kelvin.jpl.nasa.gov
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Einstein's brain is stored
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | in a mason jar in a lab
|_____|/  |_|/       |_____|/                     | in Wichita, Kansas.

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