KPL/IK HERA Asteroid Framing Camera Instrument kernel ============================================================================== This instrument kernel (I-kernel) contains the Asteroid Framing Camera (AFC) optics, detector, and field-of-view parameters. Version and Date ------------------------------------------------------------------------------ Version 0.5 -- May 22, 2024 -- Ricardo Valles, ESAC/ESA Updated parameters of Asteroid Framing Cameras following latest calibration report, removed filters and fixed typos. Version 0.4 -- Sep 21, 2023 -- Ricardo Valles, ESAC/ESA Updated Hera ID according to one provided by DSN and confirmed by FDy: from -999 to -91. Version 0.3 -- September 6, 2019 -- Marc Costa Sitja, ESAC/ESA Updated Hera ID according to standard ESOC provisional numbering: from -667 to -999. Version 0.2 -- March 2, 2019 -- Marc Costa Sitja, ESAC/ESA Updated AFCs FOV_FRAMES from HERA_AFC to HERA_AFC-1 and HERA_AFC-2 accordingly. Version 0.1 -- January 22, 2019 -- Marc Costa Sitja, ESAC/ESA Added Asteroid Framing Camera 2. Version 0.0 -- December 3, 2018 -- Marc Costa Sitja, ESAC/ESA Initial release based on DAWN Framing Camera instrument kernel. References ------------------------------------------------------------------------------ 1. ``Kernel Pool Required Reading'' 2. ``C-kernel Required Reading'' 3. Hera Frames Definition Kernel (FK), latest version. 4. Email communication from Jean-Baptiste Vincent, DLR, 8th May 2024. 5. Data sheet ASTROhead Cam, Jena-Optronik GmbH, April 2024. Contact Information ----------------------------------------------------------------------------- If you have any questions regarding this file contact the ESA SPICE Service at ESAC: Alfredo Escalante Lopez (+34) 91-8131-429 spice@sciops.esa.int or NAIF at JPL: Boris Semenov +1 (818) 354-8136 Boris.Semenov@jpl.nasa.gov Implementation Notes ------------------------------------------------------------------------------ Applications that need SPICE I-kernel data must ``load'' the I-kernel file, normally during program initialization. Loading the kernel using the SPICELIB routine FURNSH causes the data items and their associated values present in the kernel to become associated with a data structure called the ``kernel pool''. The application program may then obtain the value(s) for any IK data item using the SPICELIB routines GDPOOL, GIPOOL, GCPOOL. Routine GETFOV may be used if the file contains instrument field-of-view (FOV) specification. See [1] for details. This file was created with, and can be updated with a text editor or word processor. Naming Conventions ------------------------------------------------------------------------------ Data items are specified using ``keyword=value'' assignments [1]. All keywords referencing values in this I-kernel start with the characters `INS' followed by the NAIF HERA instrument ID code, constructed using the spacecraft ID number (-91) followed by the NAIF three digit ID number. This number identifies the generic AFCs, or the radiator. The ID numbers are defined in [3] as follows: Instrument name ID -------------------- ------- HERA_AFC-1 -91110 HERA_AFC-2 -91120 The remainder of the keyword is an underscore character followed by the unique name of the data item. For example, the f/ratio of the AFC-1 is specified by INS-91110_F/RATIO The upper bound on the length of all keywords is 32 characters. If a keyword is included in more than one file, or if the same keyword appears more than once within a single file, the last assignment supersedes any earlier assignments. Description ------------------------------------------------------------------------------ From [4] and [5]: The HERA Asteroid Framing Camera is a compact and lightweight space camera for the visible range with grayscale image output. It was designed from Jena-Optronik's heritage from the ASTRO star sensor series. It has a FaintStar2 detector with APS CMOS technology. The active area of the ASTROhead Cam CCD is sized 1024 x 1024 pixels or 10.24 x 10.24 mm (10.00 x 10.00 micron per pixel), with an image size of 1020 x 1020 pixels. It uses a refractive optic with a focal length of 106mm, a rad-hard glass material with a rectangular field-of-view of 5.5 x 5.5 degrees. These are some specification of the AFCs from [5]: ------------------------------------------------------------------ Specification ------------------------------------------------------------------ Detector FaintStar APS CMOS technology Dimension 80 x 80 x 88 mm3 Without baffle, excluding alignment cube Mass approx. 0,9 kg Power consumption 0.9 Watts, 28V Temperature range -30C..+60C Operational -40C..+70C Non-operational Detector Resolution 1024 x 1024 pixels Optics refractive, Rad-hard glass material focal length 106 mm, 5.5 x 5.5 degrees f/4.2 Pupil diameter, mm 25.2 25.2 f/ratio f/4.2 f/4.2 IFOV, rad/pixel 0.0000937 0.0000937 Field of view, deg 5.5 5.5 ------------------------------------------------------------------ Mounting Alignment ------------------------------------------------------------------------------ Refer to the latest version of the HERA Frames Definition Kernel (FK) [3] for the AFC reference frame definitions and mounting alignment information. Apparent FOV Layout ------------------------------------------------------------------------------ This section provides a diagram illustrating the AFC-1 and AFC-2 apparent FOV layout in the corresponding reference frames. Pixel (0,0) is in the lower left corner of the image, and pixel (1023,1023) is in the top right corner. +X, +Y, +Z axes are defined in the HERA Frames Definition Kernel (FK) [3]. | 5.5 deg | Boresight (+Z axis) |<--------------->| is into the page | | 1024 pixels/line --- +-----------------+ | | +Zafc1 | | | +Zafc2 | | 5.5 deg 1024 | x------------> +Xafc1 | lines | | | +Xafc2 v | | | --- (0,0)------|--------+ Pixel | | +Yafc1 v +Yafc2 FOV Definitions ------------------------------------------------------------------------------ This section contains definitions for the AFC FOVs. These definitions are provided in a format required by the SPICE (CSPICE) function GETFOV (getfov_c). The set of assignments in the data section below defines the AFC FOVs with respect to the corresponding frames to be a rectangle with the corners defined by the first and last pixels of the first and last lines of the CCD and the boresight along the +Z axis. This FOV definition uses the FOV_ANGULAR_SIZE values from the ``Optical Parameters'' section above converted to degrees. AFC-1 \begindata INS-91110_NAME = 'HERA_AFC-1' INS-91110_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-91110_FOV_FRAME = 'HERA_AFC-1' INS-91110_FOV_SHAPE = 'RECTANGLE' INS-91110_FOV_CLASS_SPEC = 'ANGLES' INS-91110_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-91110_FOV_REF_ANGLE = ( 2.75 ) INS-91110_FOV_CROSS_ANGLE = ( 2.75 ) INS-91110_FOV_ANGLE_UNITS = 'DEGREES' \begintext AFC-2 \begindata INS-91120_NAME = 'HERA_AFC-2' INS-91120_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-91120_FOV_FRAME = 'HERA_AFC-2' INS-91120_FOV_SHAPE = 'RECTANGLE' INS-91120_FOV_CLASS_SPEC = 'ANGLES' INS-91120_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-91120_FOV_REF_ANGLE = ( 2.75 ) INS-91120_FOV_CROSS_ANGLE = ( 2.75 ) INS-91120_FOV_ANGLE_UNITS = 'DEGREES' \begintext Optical Parameters ------------------------------------------------------------------------------ The following AFCs nominal first order optical parameters are, from [4]: ------------------------------------------------------------------ parameter AFC-1 AFC-2 ------------------------------------------------------------------ Focal Length, mm 106.0 106.0 Pupil diameter, mm 25.2 25.2 f/ratio f/4.2 f/4.2 IFOV, rad/pixel 0.0000937 0.0000937 Field of view, deg 5.5 5.5 ------------------------------------------------------------------ The keywords below provide the optical parameters of both cameras. Angular size values are given in radians. Focal length is given in mm, and its uncertainty is 0.01 mm. The FOV is calculated from the focal length given here and the pixel dimensions specified in the ``CCD Parameters'' section; it does not include the radial distortion described in the ``Optical Distortion'' section. The first vector element of the IFOV and FOV angular size keywords refers to the X direction, the second to the Y direction. AFC-1 \begindata INS-91110_FOCAL_LENGTH = ( 106.0 ) INS-91110_IFOV = ( 0.0000937, 0.0000937 ) INS-91110_FOV_ANGULAR_SIZE = ( 0.0959931, 0.0959931 ) INS-91110_F/RATIO = ( 4.2 ) \begintext AFC-2 \begindata INS-91120_FOCAL_LENGTH = ( 106.0 ) INS-91120_IFOV = ( 0.0000937, 0.0000937 ) INS-91120_FOV_ANGULAR_SIZE = ( 0.0959931, 0.0959931 ) INS-91120_F/RATIO = ( 4.2 ) \begintext CCD Parameters ------------------------------------------------------------------------------ The AFCs use a CCD detector of the same type with the following nominal geometry parameters, from [4]. Note that the pixels are not perfectly square, as described in the ``Optical Parameters'' section. -------------------------------------------- parameter value -------------------------------------------- Pixel Size, microns 10.00 Detector Array Size 1024 Detector Array Center 511.5 -------------------------------------------- The values are given in microns for PIXEL_SIZE keywords and in counts for PIXEL_SAMPLES, PIXEL_LINES, and CENTER keywords. AFC-1 optical parameters \begindata INS-91110_PIXEL_SIZE = ( 10.00, 10.00 ) INS-91110_PIXEL_SAMPLES = ( 1024 ) INS-91110_PIXEL_LINES = ( 1024 ) INS-91110_CCD_CENTER = ( 511.5, 511.5 ) \begintext AFC-2 optical parameters \begindata INS-91120_PIXEL_SIZE = ( 10.00, 10.00 ) INS-91120_PIXEL_SAMPLES = ( 1024 ) INS-91120_PIXEL_LINES = ( 1024 ) INS-91120_CCD_CENTER = ( 511.5, 511.5 ) \begintext Spectral Parameters ------------------------------------------------------------------------------ This section contains AFCs spectral parameters. The following band center and band width in nm data are taken from [4]. ------------------------------------------------------------------ parameter AFC-1 AFC-2 ------------------------------------------------------------------ Spectral range, nm 400-900 400-900 Band center, nm 650 650 Band width, nm 500 500 Dynamic range, bits 12 12 ------------------------------------------------------------------ Given below are the center wavelength (BANDCENTER), the band width (BANDWIDTH) for each of the AFCs, all in nm. AFC-1 spectral parameters \begindata INS-91110_BANDCENTER = ( 650 ) INS-91110_BANDWIDTH = ( 500 ) \begintext AFC-2 spectral parameters \begindata INS-91120_BANDCENTER = ( 650 ) INS-91120_BANDWIDTH = ( 500 ) \begintext Optical Distortion ------------------------------------------------------------------------------ TBD. End of IK file.