[sci.astro] Magellan Update - 12/13/90

baalke@mars.jpl.nasa.gov (Ron Baalke) (12/14/90)

                         MAGELLAN STATUS REPORT
                           December 13, 1990

     The Magellan spacecraft is in good health and performing nominally.  All
seven STARCALS (star calibrations) since yesterday were successful with small
attitude updates.

     The spacecraft commanding at present includes updating of reference
values such as the Z axis gyro bias.  Tomorrow, however, the M0349 mapping
sequence will be sent up, which is the first of six occulted mapping sequences.
This sequence will shorten the mapping pass by 6.5 minutes in order to
accommodate 46 minutes of earth occultation during the playback.

     Spacecraft engineers are meeting today with representatives of Odectics,
the company which built the on-board tape recorder to discuss the probable
causes of the tape recorder A deterioration and options for correcting the
problem.

     96.7% of the radar data has been received at Earth.  The following
table shows the causes of data losses:

           Power outage at Madrid DSN station (10/1) 1.2 orbits
           Incorrect attitude update (10/1)          1.5 orbits
           DSN delay is setting polarization after
             TWTA swap following spurious shutoff    0.3 orbits
           Frequency timing outage Canberra (11/13)  1.4 orbits
           Loss of Signal #3 (11/15)                 3.0 orbits
           Power outage at Canberra (11/21)          0.2 orbits
           Tweak Commanding anomaly (11/23)          4.0 orbits
           Incorrect attitude update (12/1)          4.5 orbits
           Miscellaneous DSN lockup delays, etc.     0.4 orbits
               TOTAL TO DATE:                       16.5 ORBITS

     Eight images have been selected for a Magellan Results lithograph set to
be distributed Lab-wide early in 1991. A 10 foot by 12 foot photomural of the
"Crater Farm" Magellan image has been hung on the wall opposite the entrance
to the Smithsonian National Air and Space Museum in Washington, D.C., and a
continuous video presentation which includes the press conference is playing
on the main floor near the Viking display.
      ___    _____     ___
     /_ /|  /____/ \  /_ /|
     | | | |  __ \ /| | | |      Ron Baalke         | baalke@mars.jpl.nasa.gov
  ___| | | | |__) |/  | | |___   Jet Propulsion Lab | baalke@jems.jpl.nasa.gov
 /___| | | |  ___/    | |/__ /|  M/S 301-355        |
 |_____|/  |_|/       |_____|/   Pasadena, CA 91109 |