From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Ulysses Update - 08/10/92
Keywords: Ulysses, JPL, ESA
Date: 13 Aug 92 08:19:56 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. 103

PERIOD: 4th to 10th August 1992

1. MISSION OPERATIONS

     Experiment reconfigurations have been carried out as required.

     Routine Earth pointing manoeuvres were performed on 7th
     and 10th August.

     On 6th August a lightning strike on the Madrid 34 meter
     antenna took the station out of service.  As a result nearly
     24 hours of data were lost.  The next dump of the tape
     recorder was saved by scheduling the playback operation via
     the Canberra 70 meter antenna.

     On 7th August problems were still being experienced with
     bringing the Madrid 34 meter antenna back into service with
     the result that a further 7 hours of real time data were
     lost.  The station was eventually brought back into service
     in a degraded mode of operation.  However, the performance
     was adequate to allow data recovery to continue.

     On 10th August, the Madrid 34 meter antenna was restored to
     its normal operational configuration.

     The KEP GAS Health check was not carried out as a result of
     the above ground segment problems.

     An average of 81.11 % data recovery was achieved during the
     reporting period.

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

     1024 bps 49.19 %
      512 bps 39.65 %

     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 -127 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 4.23 on
     Angle (deg.)   4th August to 3.86 on 10th August.

     Sun-Probe-Earth  The angle decreased from 4.50 on
     Angle (deg.)     4th August to 3.70 on 10th August.

     Spin Rate               4.982 rpm.

4.   ORBITAL DATA

     Data taken at 13:00 PDT on 10th August.
     Distance from Earth                933,988,892 km.
     Velocity relative to the Earth         111,027 km/hr.
     Velocity relative to the Sun            30,690 km/hr.
     Ecliptic latitude                          8.0 deg/south

5.   PLANNED OPERATIONS

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

     An Earth pointing manoeuvre will be performed on 13th and
     16th August.

     The KEP GAS Health check will be carried out during the next
     reporting period.

     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 performance suffered as a result of a
     lightning strike at the Madrid 34 meter site.  Much effort
     was made to restore the capability as quickly as possible.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | baalke@kelvin.jpl.nasa.gov
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | You can't hide broccoli in
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | a glass of milk - 
|_____|/  |_|/       |_____|/                     | anonymous 7-year old.
Newsgroups: sci.space.news