 
 
Mars Global Surveyor Antenna Structures SPK File
================================================================================
 
   This SPK file (FK) contains location of various MGS antenna structures
   with respect to each other.
 
 
If You're in a Hurry
-------------------------------------------------------------------------------
 
   In case you are not interested in details and just looking for the right
   NAIF code of a particular MGS antenna center to use it in a call to SPKEZ,
   here is the list:
 
         -94         s/c ID;
         -94000      s/c frame center ID;
         -94073      HGA center ID (reflector axis @ reflector rim plane);
         -94074      LGT1 center ID (center of the patch);
         -94075      LGT2 center ID (center of the patch);
         -94076      LGR1 center ID (center of the patch);
         -94077      LGR2 center ID (center of the patch);
         -94078      HGA phase center (currently same point as -94073).
 
 
Version and Date
--------------------------------------------------------
 
   Version 1.1 -- March 30, 1999
 
      Added zero offset between s/c center of mass and spacecraft frame
      center to close the SPK chain. In reality location of the center of
      mass moves with respect to the spacecraft frame.
 
   Version 1.0 -- March 1, 1999
 
      Initial Release.
 
 
Contact Information
-------------------------------------------------------------------------------
 
   Boris V. Semenov, NAIF/JPL, (818)-354-8136, bsemenov@spice.jpl.nasa.gov
 
 
References
-------------------------------------------------------------------------------
 
   1. Complete Set of MGS Mechanical Drawings, 1997.
 
   2. ``Frames Required Reading''
 
   3. ``SP-Kernel Required Reading''
 
   4. ``C-Kernel Required Reading''
 
 
Related SPICE Kernels
-------------------------------------------------------------------------------
 
   Descriptions/definitions from the MGS HGA Frame definitions kernel file
   are required in order to understand objects and frames with respect to
   which the locations are defined in this SPK file.
 
 
What is relative to what and in what frame?
----------------------------------------------------------------------
 
   -94000   MGS_SPACECRAFT frame center, offset relative to the MGS
            spacecraft center of mass (-94) in the MGS_SPACECRAFT frame;
 
   -94070   MGS_HGA_HINGE frame center, offset relative to the MGS
            spacecraft frame center (-94000) in the MGS_SPACECRAFT frame;
 
   -94071   MGS_HGA_EL_GIMBAL frame center, offset relative to the
            MGS_HGA_HINGE frame center (-94070) in the MGS_HGA_HINGE frame;
 
   -94072   MGS_HGA_AZ_GIMBAL frame center, offset relative to the
            MGS_HGA_EL_GIMBAL frame center (-94071) in the MGS_HGA_EL_GIMBAL
            frame;
 
   -94073   MGS_HGA frame center, offset relative to the MGS_HGA_AZ_GIMBAL
            frame center (-94072) in the MGS_HGA_AZ_GIMBAL frame;
 
   -94074   MGS_LGT1 frame center, offset relative to the MGS_HGA
            frame center (-94073) in the MGS_HGA frame;
 
   -94075   MGS_LGT2 frame center, offset relative to the MGS_HGA
            frame center (-94073) in the MGS_HGA frame;
 
   -94076   MGS_LGR1 frame center, offset relative to the MGS
            spacecraft frame center (-94000) in the MGS_SPACECRAFT frame;
 
   -94077   MGS_LGR2 frame center, offset relative to the MGS
            spacecraft frame center (-94000) in the MGS_SPACECRAFT frame;
 
   -94078   HGA phase center, offset relative to the MGS_HGA
            frame center (-94073) in the MGS_HGA frame;
 
 
MGS HGA Boom/Gimbal Diagram
----------------------------------------------------------------------
 
   The diagram below illustrates relative locations of the HGA hinge/gimbal/
   boresight frame centers (the antenna is shown as if it would be fully
   extended along  s/c +X axis in the s/c XY plane; dimensions are given in
   inches):
 
   Top view (+Zsc view):
   ---------------------
                                            * * * * *
                                         *             *
                                       *                 *
                                      *                   *
                                     *                     *
                                    *                       *
                                    *                       *
       ---------------------------- *           o           *
        ^                           *                       *
        |                           *                       *
        | 27.33"                    *                       *
        |                            *                     *
        |                             *                   *
        |                               *               *____
        v                                 *          __|     |_____
       ------------------------------------ * * o__*___|      ___ o|
        ^                                              |_____|   | |
        |                                            azimuth    _|_|_
        |         ______                             gimbal    |     | elev.
        | 14.33"        |                                      |     | gimbal
        |               |____                                  |_____|
        v              |     |___________________________________| |
       --------------- |  o   _____________________________________|
        |              |_____|
       ------ o         | deployment
        ^               |   hinge
        | 13.00"        |
                        |
                        |
                ________|
 
 
   Side view (-Ysc view):
   ----------------------
 
 
    ------------------------------   ___________o___________
      ^                 |            \__                 __/
      | 12.06"          |___            \__           __/____    ___
      v                 /   \______________\_________/_|_____|_ /   \
    --------  _________|  o  ___________________o______________|  o  |
      ^          \      \___/                          |_____|  \___/
      | 6.788"    \                             |
      v            \      |                     |                |
    ------  __o_____\     |                     |     31.655"    |
                          |                     |<-------------->|
              |           |                     |                |
              |           |                                      |
              |   27.25"  |                90.778"               |
              |<--------->|<------------------------------------>|
              |           |                                      |
 
 
MGS LGT1/LGT2 Diagram
----------------------------------------------------------------------
 
   The diagram below illustrates location of the LGT1 and LGT2 with respect
   to the HGA boresight frame (dimensions are given in inches):
 
   Front View (+Zb):
   -----------------
                                       ^
                                       | +Yb
                         TWA     _/\
                         box   _/   \
                             _/    * * * * *
                           _/    *           *
                     LGR2_/    * *             *
            ------------/@   *    *              *
             ^  --------\ @ LGR1   *              *
       15.41"|   ^       \_*        *              *
             |   |15.31" ||*         * _           *
             V   V       ||*          / \          *
            ------------ ||*         | o |* * * * **  --> +Xb
                         ||*          \_/          *
                         ||*         *             *
                         ||*        *              *
                         || *      *              *
                         ||  *    *              *
                         ||   *  *              *
                         ||     *             *
                         ||        * * * * *
                         ||   28.18"   |
                         ||<---------->|
                         |             |
                         |<----------->|
                              30.05"
 
   Side View (-Xb):
   ----------------
                                ~18.6"
                             |<------->|
                             |         |  ~0"
                             |       ->|<-----
                             |  _____
                             | | TWA |
                             | | box |/|
                             | |     | | \
                               |_____| |
                        LGR2 @=|     | |   \
                               |     |=@
                               |_____| |LGR1 \
                                /      |
                               |       |      /
                               |       o - - |  Sub-reflector
                               |       |      \
                                \      |
                                 |     |     /
                                  \    |
                                   |   |   /
                                    \  |
                                     | | /
                                      \|
 
 
MGS LGR1/LGR2 Diagram
----------------------------------------------------------------------
 
   The diagram below illustrates location of the LGR1 and LGR2 with respect
   to the spacecraft frame (the HGA is shown in stowed configuration;
   dimensions are given in inches):
 
 
   Top View (+Zsc):
   ----------------
 
                       ^ +Ysc
                       |
                       |           __
                  ___________ LGR1/  |   |
                 |           |   /   |   v
           |     |           |=@/    | -----
         0"|     |           | /     |   | 5.29"
           v     |           ||  HGA |   |
         ----- @=|     o     ||__    | -----      --->
           ^ LGR2|           ||  |   |   ^        +Xsc
           |     |           ||  |   |   |
                 |           ||  |   |
                 |___________||  |   |
                              |  |\__|
                              |  |=@
                            @=|__|
                          LGT2    LGT1
 
   Side View (-Ysc):
   -----------------
 
                       ^ +Zsc
                       |
                       |
                          LGT2 __  LGT1
                            @=|  |=@
                              |  | __
                              |__|/  |
                  ___________    /   |
                 |           |  /    |
                 |           | /     |
                 |           ||      |
             LGR2|           ||      | HGA
         ----- @=|           ||      |
           ^   | |___________| \     |
           |   | |           |  \    |
           |   | |           |   \   |
           |   | |           |    \__|
     49.94"|   | |           |
           |   | |           | LGR1
           |   | |           |=@ ---
           |   | |___________| |  ^
           |   |     /   \     |  | 17.56"
           |   |    /     \    |  |
           v   |   /       \   |  v
         ------+- +----o----+  -+----       --->
               |       |       |            +Xsc
               |<----->|<----->|
                 25.81"  31.75"
 
 
Coordinates
----------------------------------------------------------------------
 
   This table contains coordinates of various antenna structures with respect
   to each other (refer to the diagrams above for clarification):
 
      ID     CENTER   FRAME                X,inch   Y,inch   Z,inch
   -------  -------  --------------------  -------  -------  -------
   -94000   -94      MGS_SPACECRAFT         +0.000   +0.000   +0.000
   -94070   -94000   MGS_SPACECRAFT        +27.250  +13.000   +6.788
   -94071   -94070   MGS_HGA_HINGE         +90.778    0.000  +14.330
   -94072   -94071   MGS_HGA_EL_GIMBAL     +31.655    0.000    0.000
   -94073   -94072   MGS_HGA_AZ_GIMBAL     +27.330  -12.060    0.000
   -94074   -94073   MGS_HGA               -28.180  +15.310    0.000
   -94075   -94073   MGS_HGA               -30.050  +15.410  -18.600
   -94076   -94000   MGS_SPACECRAFT        +31.750   +5.290  +17.560
   -94077   -94000   MGS_SPACECRAFT        -25.810    0.000  +49.940
   -94078   -94073   MGS_HGA                 0.000    0.000    0.000
 
   Same in meters:
 
      ID     CENTER   FRAME                  X,m      Y,m      Z,m
   -------  -------  --------------------  -------  -------  -------
   -94000   -94      MGS_SPACECRAFT         0.000    0.000    0.000
   -94070   -94000   MGS_SPACECRAFT         0.692    0.330    0.172
   -94071   -94070   MGS_HGA_HINGE          2.306    0.000    0.364
   -94072   -94071   MGS_HGA_EL_GIMBAL      0.804    0.000    0.000
   -94073   -94072   MGS_HGA_AZ_GIMBAL      0.694   -0.306    0.000
   -94074   -94073   MGS_HGA               -0.716    0.389    0.000
   -94075   -94073   MGS_HGA               -0.763    0.391   -0.472
   -94076   -94000   MGS_SPACECRAFT         0.806    0.134    0.446
   -94077   -94000   MGS_SPACECRAFT        -0.656    0.000    1.268
   -94078   -94073   MGS_HGA                0.000    0.000    0.000
 
   Same in km -- is used below is PINPOINT keywords:
 
      ID     CENTER   FRAME                   X,km       Y,km        Z,km
   -------  -------  --------------------  ---------  ----------  ----------
   -94000   -94      MGS_SPACECRAFT         0.000000    0.000000    0.000000
   -94070   -94000   MGS_SPACECRAFT         0.000692    0.000330    0.000172
   -94071   -94070   MGS_HGA_HINGE          0.002306    0.000000    0.000364
   -94072   -94071   MGS_HGA_EL_GIMBAL      0.000804    0.000000    0.000000
   -94073   -94072   MGS_HGA_AZ_GIMBAL      0.000694   -0.000306    0.000000
   -94074   -94073   MGS_HGA               -0.000716    0.000389    0.000000
   -94075   -94073   MGS_HGA               -0.000763    0.000391   -0.000472
   -94076   -94000   MGS_SPACECRAFT         0.000806    0.000134    0.000446
   -94077   -94000   MGS_SPACECRAFT        -0.000656    0.000000    0.001268
   -94078   -94073   MGS_HGA                0.000000    0.000000    0.000000
 
 
Data section of the file.
----------------------------------------------------------------------
 
   \begindata
 
   SITES                            = (
                                      'MGS_SPACECRAFT_CENTER'
                                      'MGS_HGA_HINGE_CENTER'
                                      'MGS_HGA_EL_GIMBAL_CENTER'
                                      'MGS_HGA_AZ_GIMBAL_CENTER'
                                      'MGS_HGA_CENTER'
                                      'MGS_LGT1_CENTER'
                                      'MGS_LGT2_CENTER'
                                      'MGS_LGR1_CENTER'
                                      'MGS_LGR2_CENTER'
                                      'HGA_PHASE_CENTER'
                                      )
 
   MGS_SPACECRAFT_CENTER_IDCODE     = -94000
   MGS_SPACECRAFT_CENTER_CENTER     = -94
   MGS_SPACECRAFT_CENTER_FRAME      = 'MGS_SPACECRAFT'
   MGS_SPACECRAFT_CENTER_XYZ        = ( 0.000000    0.000000    0.000000 )
 
   MGS_HGA_HINGE_CENTER_IDCODE      = -94070
   MGS_HGA_HINGE_CENTER_CENTER      = -94000
   MGS_HGA_HINGE_CENTER_FRAME       = 'MGS_SPACECRAFT'
   MGS_HGA_HINGE_CENTER_XYZ         = ( 0.000692    0.000330    0.000172 )
 
   MGS_HGA_EL_GIMBAL_CENTER_IDCODE  = -94071
   MGS_HGA_EL_GIMBAL_CENTER_CENTER  = -94070
   MGS_HGA_EL_GIMBAL_CENTER_FRAME   = 'MGS_HGA_HINGE'
   MGS_HGA_EL_GIMBAL_CENTER_XYZ     = ( 0.002306    0.000000    0.000364 )
 
   MGS_HGA_AZ_GIMBAL_CENTER_IDCODE  = -94072
   MGS_HGA_AZ_GIMBAL_CENTER_CENTER  = -94071
   MGS_HGA_AZ_GIMBAL_CENTER_FRAME   = 'MGS_HGA_EL_GIMBAL'
   MGS_HGA_AZ_GIMBAL_CENTER_XYZ     = ( 0.000804    0.000000    0.000000 )
 
   MGS_HGA_CENTER_IDCODE            = -94073
   MGS_HGA_CENTER_CENTER            = -94072
   MGS_HGA_CENTER_FRAME             = 'MGS_HGA_AZ_GIMBAL'
   MGS_HGA_CENTER_XYZ               = ( 0.000694   -0.000306    0.000000 )
 
   MGS_LGT1_CENTER_IDCODE           = -94074
   MGS_LGT1_CENTER_CENTER           = -94073
   MGS_LGT1_CENTER_FRAME            = 'MGS_HGA'
   MGS_LGT1_CENTER_XYZ              = ( -0.000716    0.000389    0.000000 )
 
   MGS_LGT2_CENTER_IDCODE           = -94075
   MGS_LGT2_CENTER_CENTER           = -94073
   MGS_LGT2_CENTER_FRAME            = 'MGS_HGA'
   MGS_LGT2_CENTER_XYZ              = ( -0.000763    0.000391   -0.000472 )
 
   MGS_LGR1_CENTER_IDCODE           = -94076
   MGS_LGR1_CENTER_CENTER           = -94000
   MGS_LGR1_CENTER_FRAME            = 'MGS_SPACECRAFT'
   MGS_LGR1_CENTER_XYZ              = ( 0.000806    0.000134    0.000446 )
 
   MGS_LGR2_CENTER_IDCODE           = -94077
   MGS_LGR2_CENTER_CENTER           = -94000
   MGS_LGR2_CENTER_FRAME            = 'MGS_SPACECRAFT'
   MGS_LGR2_CENTER_XYZ              = ( -0.000656    0.000000    0.001268 )
 
   HGA_PHASE_CENTER_IDCODE          = -94078
   HGA_PHASE_CENTER_CENTER          = -94073
   HGA_PHASE_CENTER_FRAME           = 'MGS_HGA'
   HGA_PHASE_CENTER_XYZ             = ( 0.000000    0.000000    0.000000 )
 
   \begintext
 
 
