From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Ulysses Update - 07/20/92
Keywords: Ulysses, JPL, ESA
Date: 23 Jul 92 01:13:18 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 Peter Beech, Ulysses Mission Operations Manager

SUBJECT:  ULYSSES MISSION OPERATIONS REPORT No. 100

PERIOD:   14th July to 20th July 1992


1. MISSION OPERATIONS

     Experiment reconfigurations have been carried out as
     required.

     Routine Earth pointing manoeuvres were performed on 14th,
     17th and 20th July.

     An average of 97.10 % data recovery was achieved during
     the reporting period.

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

     1024 bps 48.26 %
      512 bps 48.75 %

     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 -149 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 7.14 on
     Angle (deg.)   14th July to 6.31 on 20th July.

     Sun-Probe-Earth  The angle decreased from 7.16 on
     Angle (deg.)     14th July to 6.32 on 20th July.

     Spin Rate               4.982 rpm.



4.   ORBITAL DATA

     Data taken at 13:00 PDT on 20th July.
     Distance from Earth                914,643,627 km.
     Distance from Jupiter              193,598,524 km.
     Velocity relative to the Sun            30,388 km/hr.
     Velocity relative to the Earth         107,340 km/hr.


5.   PLANNED OPERATIONS

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

     Earth pointing manoeuvres will be performed on 24th
     and 27th July.

     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.

     DSS 14 (Goldstone 70 meter antenna) will be out of
     commission until at least 23rd July because of damage to
     the subreflector during the earthquakes.  A few delta dor
     (Differential One-way Ranging) passes will be lost although
     some will be switched to DSS 15 (Goldstone 34 meter antenna).
     Some reduction of 1024 bps data will arise as a result of
     rescheduling of passes to help projects who were supposed to
     use DSS 14.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     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
|_____|/  |_|/       |_____|/                     | happen.
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