KPL/IK
\beginlabel
PDS_VERSION_ID = PDS3
RECORD_TYPE = STREAM
RECORD_BYTES = "N/A"
^SPICE_KERNEL = "MGS_MOLA_V22.TI"
MISSION_NAME = "MARS GLOBAL SURVEYOR"
SPACECRAFT_NAME = "MARS GLOBAL SURVEYOR"
DATA_SET_ID = "MGS-M-SPICE-6-V1.0"
KERNEL_TYPE_ID = IK
PRODUCT_ID = "MGS_MOLA_V22.TI"
PRODUCT_CREATION_TIME = 2000-01-04T09:41:59
PRODUCER_ID = "NAIF/JPL"
MISSION_PHASE_NAME = "N/A"
PRODUCT_VERSION_TYPE = ACTUAL
PLATFORM_OR_MOUNTING_NAME = "MGS NADIR DECK"
START_TIME = "N/A"
STOP_TIME = "N/A"
SPACECRAFT_CLOCK_START_COUNT = "N/A"
SPACECRAFT_CLOCK_STOP_COUNT = "N/A"
TARGET_NAME = MARS
INSTRUMENT_NAME = "MARS ORBITER LASER ALTIMETER"
NAIF_INSTRUMENT_ID = -94040
SOURCE_PRODUCT_ID = "N/A"
NOTE = "See comments in the file for details"
OBJECT = SPICE_KERNEL
INTERCHANGE_FORMAT = ASCII
KERNEL_TYPE = INSTRUMENT
DESCRIPTION = "MGS Mars Orbiter Laser Altimeter instrument
parameters SPICE I-Kernel File. This file also contains MOLA Frame
definitions and location of the MGS antenna phase centers and center of
gravity for some spacecraft configurations."
END_OBJECT = SPICE_KERNEL
\endlabel
MOLA Instrument Kernel
===========================================================================
This instrument kernel (I-kernel) contains the Mars Orbiter Laser
Altimeter (MOLA) instrument mounting offset, intrument frame definition
and instrument location.
Version and Date
--------------------------------------------------------
Version 2.2 -- May 27, 1998
Added section contaning coordinates of the HGA and LGAs geometric
centers in stowed position.
Version 2.1 -- August 25, 1997
Z coordinate of MOLA was changed to be 1.9202 meters (old value 1.9116
meters) after confirmation from Rich Hund of LMA.
Version 2.0 -- August 19, 1997
Section specifying location of MOLA, s/c center of mass and s/c
frame origin was added.
Version 1.2 -- August 11, 1997
Frame definition was corrected to represent the correct
transformation sense.
Version 1.1 -- June 19, 1997
The MOLA frame definition section was added to support utilization of
the SPICE system FRAMES capabilities.
Version 1.0 -- November 26, 1996
Initial Release.
References
--------------------------------------------------------
1. ``MGS Alignment Transformation'', by Richard A. Hund,
November 26, 1996.
2. ``MGS Payload Data Sheet'' by C.Kloss, October 31, 1995,
3. ``C-kernel Required Reading''
4. ``Kernel Pool Required Reading''
5. ``Frames Required Reading''
6. ``MGS Mission Specification. Mission Requirements and
Vehicle Description'', MDC 95H0026B, MGS REV B. APRIL 1996.
7. ``Nadir Equipment Deck. Science Instrument Configuration"
DWG, 23 Jan 1995; provived by Carl Kloss.
8. Phone message from Jon Nichols re. location of the spacecarft's
center of mass during mapping phase of the mission; August 13, 1997.
Implementation Notes
--------------------------------------------------------
This file is used by the SPICE system as follows: programs that make
use of this I-kernel must `load' the kernel, normally during program
initialization. Loading the kernel associates data items with their
names in a data structure called the `kernel pool'. The SPICELIB
routine LDPOOL loads a kernel file into the pool as shown below.
CALL LDPOOL ( I_kernel_name )
In order for a program or subroutine to extract data from the pool,
the SPICELIB routines GDPOOL and GIPOOL are used. See [4] for more details.
This file was created and may be updated with a text editor or word
processor.
Naming Conventions
--------------------------------------------------------
All names referencing values in this I-kernel start with the
characters `INS' followed by the NAIF Mars Global Surveyor spacecraft ID
number (-94) followed by the NAIF three digit MOLA instrument
reference number (040).
The remainder of the name is an underscore character followed by the
unique name of the data item. For example, the MOLA offset relative to
the spacecraft frame, given as three Euler angles, is specified using
two items:
INS-94040_EULER_ANGLES
INS-94040_EULER_AXES
The upper bound on the length of the name of any data item is 32
characters.
If the same item is included in more then one file, or if the same
item appears more than once within a single file, the latest value
supersedes any earlier values.
MOLA mounting offset
--------------------------------------------------------
This section describes the offset of the MOLA instrument fixed frame
(the frame fixed to the alignment cube on the MOLA) relative to the
Mars Global Surveyor spacecraft frame. From the offset, given as three
rotation angles -- ROLL, PITCH and YAW, a rotation matrix can be
constructed that will transform the components of a vector expressed
in the spacecraft frame to components expressed in the MOLA instrument
fixed frame. For example, if x y and z are the components of a vector
expressed in the spacecraft frame, X Y and Z will be the components
of the same vector expressed in the MOLA instrument fixed frame:
[ X ] [ ] [ x ]
| Y | = | ROT | | y |
[ Z ] [ ] [ z ]
where ROT is the rotation matrix constructed from the rotation angles
as follows:
[ ] [ ] [ ] [ ]
[ ROT ] = [ YAW ] [ PITCH ] [ ROLL ]
[ ] [ ] [ ] [ ]
Z Y X
where each of three matrixes on the right side represent a coordinate
frame rotation by the given angle around the indicated axis. See the
SPICELIB routine EUL2M for more information about constructing
a rotation matrix from a set of rotation angles.
The following measured values of ROLL, PITCH and YAW are provided in [1]:
ROLL = 0.021 (degrees)
PITCH = 359.995 (degrees)
YAW = 0.059 (degrees)
The keyword INS-94040_EULER_ANGLES contains these values, in radians,
in the following order:
INS-94040_EULER_ANGLES = ( ``ROLL'' ``PITCH'' ``YAW'' )
The keyword INS-94040_EULER_AXES contains integer codes of the
corresponding axes of rotations (1 -- X, 2 -- Y, 3 -- Z).
\begindata
INS-94040_EULER_ANGLES = ( 0.000366519143 6.283098040717 0.001029744259 )
INS-94040_EULER_AXES = ( 1 2 3 )
\begintext
Laser Transmitter
--------------------------------------------------------
The laser transmitter beam divergence, from [2], is 0.25 mrad. Unit are
in radians
\begindata
INS-94040_LASER_BEAM_DIVERGENCE = ( 0.00025 )
\begintext
Altimeter Receiver
--------------------------------------------------------
The altimeter receiver field of view (FOV), from [2], is cone of
0.85 mrad. Units are in radians
\begindata
INS-94040_RECEIVER_FOV = ( 0.00085 )
\begintext
Platform ID
--------------------------------------------------------
This number is the NAIF instrument ID of the platform on which the
instrument is mounted.
\begindata
INS-94040_PLATFORM_ID = ( -94000 )
\begintext
Instrument Frame Definition
--------------------------------------------------------
The instrument frame definition for MOLA. This definiton will be utilized
by SPICE's FRAMES subsystem to provide automatic state transformations
to/from MOLA instrument frame frame. Note that SPICE toolkit version N0047
or higher is required to use fixed-offset frames.
Note that angles in the frame definitions are specified for "from
instrument to base (relative to) frame" transformation.
\begindata
FRAME_MGS_MOLA = -94040
FRAME_-94040_NAME = 'MGS_MOLA'
FRAME_-94040_CLASS = 4
FRAME_-94040_CLASS_ID = -94040
FRAME_-94040_CENTER = -94
TKFRAME_-94040_SPEC = 'ANGLES'
TKFRAME_-94040_RELATIVE = 'MGS_SPACECRAFT'
TKFRAME_-94040_ANGLES = ( -0.000366519143,
-6.283098040717,
-0.001029744259 )
TKFRAME_-94040_AXES = ( 1, 2, 3 )
TKFRAME_-94040_UNITS = 'RADIANS'
\begintext
MOLA and s/c center of mass locations
--------------------------------------------------------
The locations of the MOLA instrument [ref. 6,7] and the s/c center
of mass for stowed (launch) [ref. 6] and nominal mapping [ref. 8]
configuration are specified relative to the s/c fixed which is
defined as follows:
- origin of the frame is located at the intersection of the
s/c--launch vehicle interface plane and the spacecraft's central
axis, i.e at the center of the bottom of the propulsion unit nozzle;
- Z axis is along s/c central axis; positive Z direction is from
s/c bottom towards nadir equipment deck;
- X axis is perpendicular to Z axis and points thought the side of
the s/c which high gain antenna is mounted on; positive X direction
is from the center of the s/c toward HGA side;
- Y axis completes X and Z axes to right hand frame.
The locations coordinates are given in meters.
\begindata
INS-94040_MOLA_LOC = ( 0.3383 0.3126 1.9202 )
INS-94040_SC_LAUNCH_CG_LOC = ( -0.0010 -0.0007 1.1320 )
INS-94040_SC_MAPPING_CG_LOC = ( 0.0298 0.0718 0.9970 )
\begintext
MGS Antenna Locations (stowed configuration).
--------------------------------------------------------
Three MGS antennas -- main HGA and "FRONT" and "BACK" LGAs -- in
stowed position are shown on the diagrams below:
MGS S/C "-Y" Side View:
-------------------------------------------------
^ S/C +Z Axis
|
|
39.318"
|<----------->|
| |
| 39.318" |
|<--------->| |
| | |
| 20.72" | |
|<-->| | |
|
| LGAB __LGAF
---------- @=| |=@ --------
| | __ ^
^ |__|/ | |
| +-----------+ / | |
| | | / | |
| | | / | | 81.46"
| | || | |
|81.56" || HGA | ---- |
| | || | ^ |
| | | \ | | |
| | | \ | | |
| | | \ | | |
| | | \__| | |
| +----+-+----+ | |
| / \ | |
| / \ 66.15"| |
v / \ v v
---- +----#----+ ----------------- --->
S/C Frame S/C +X Axis
Origin
MGS S/C Top View:
-------------------------------------------------
^ S/C +Y Axis
|
| __
/ |
+-----------+ / |
| | / |
| S/C Frame | / |
| Origin || HGA |
---- | # ||__ | ---- --->
^ | || | | ^ S/C +X Axis
|30.05" || | | |
| | || | | |
| +----+-+----+| | | | 28.18"
v | |\__| v
--------------- @=|__|=@ -----
LGAB LGAF
The HGA center, coordinates of which are given below, is considered
to be at the geometric center of the outside (big diameter) circle
of the antenna.
The LGA centers coordinates of which are given below are considered
to be at the geometric center of the 1.45" x 1.45" square-shaped
active element of the antenna.
In both cases, the "geometric" centers of the antennas probably
don't match with antenna's phase centers, location of which have
to be computed using complete antenna geometry.
MGS Antenna Center locations, in inches:
s/c X s/c Y s/c Z
-------- -------- ---------
HGA 39.318 0.0 66.15
"FRONT" LGA 39.318 -28.18 81.46
"BACK" LGA 20.72 -30.05 81.56
Same, in meters:
s/c X s/c Y s/c Z
-------- -------- ---------
HGA 0.999 0.000 1.680
"FRONT" LGA 0.999 -0.716 2.069
"BACK" LGA 0.526 -0.763 2.072
Cooridnates in meters are the data keywords:
\begindata
INS-94040_HGA_STOWED_LOC = ( 0.999 0.000 1.680 )
INS-94040_FRONT_LGA_STOWED_LOC = ( 0.999 -0.716 2.069 )
INS-94040_BACK_LGA_STOWED_LOC = ( 0.526 -0.763 2.072 )
\begintext