KPL/IK MERTIS Instrument Kernel =========================================================================== This instrument kernel (I-kernel) contains references to mounting alignment, operating modes, and timing as well as internal and FOV geometry for the BepiColombo MPO MErcury Radiometer and Thermal Infrared Spectrometer (MERTIS). Version and Date --------------------------------------------------------------------------- Version 0.7 -- April 14, 2021 -- Alfredo Escalante Lopez, ESAC/ESA Mario D'Amore, DLR Corrected pixel FOV definitions and fixed minor typos. Version 0.6 -- October 28, 2020 -- Marc Costa Sitja, ESAC/ESA Alessandro Maturilli, DLR Added pixel FOV definitions. Version 0.5 -- May 22, 2020 -- Marc Costa Sitja, ESAC/ESA Added optical and detector parameters for all sensors. Version 0.4 -- April 2, 2020 -- Marc Costa Sitja, ESAC/ESA FOV cross-track angles have been corrected following clarification for the Earth Flyby. Version 0.3 -- March 9, 2018 -- Marc Costa Sitja, ESAC/ESA Alessandro Maturilli, DLR Added Optical and Detector parameters. Version 0.2 -- February 15, 2017 -- Marc Costa Sitja, ESAC/ESA Updated instrument description and added main parameters table. Pending review from BepiColombo SGS and MERTIS instrument team. Version 0.1 -- July 08, 2016 -- Marc Costa Sitja, ESAC/ESA Updated BEPICOLOMBO MPO IDs from -69 to -121. Removed kernel name and version assignment. Version 0.0 -- February 11, 2013 -- Jonathan McAuliffe, ESAC/ESA Initial prototype release. References --------------------------------------------------------------------------- 1. ``Kernel Pool Required Reading'' 2. BepiColombo MPO Spacecraft Frames Definition Kernel 3. ``Frames Required Reading'' 4. ``C-Kernel Required Reading'' 5. ``The Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) for the BepiColombo mission'', Planetary and Space Science 58 (2010) 144-165. 6. ``MERTIS User Manual'' 7. ``MERITS Experiment Interface Document B (EID-B)'' 8. E-Mail ``BepiColombo New Operational Kernels Available - Earth-Flyby Kernels'' from Alessandro Maturilli (DLR), 2 April 2020. Contact Information ----------------------------------------------------------------------------- If you have any questions regarding this file contact the ESA SPICE Service at ESAC: Marc Costa Sitja (+34) 91-8131-457 marc.costa@esa.int, esa_spice@sciops.esa.int Implementation Notes ----------------------------------------------------------------------------- This file is used by the SPICE system as follows: programs that make use of this frame kernel must "load" the kernel normally during program initialization. Loading the kernel associates the data items with their names in a data structure called the "kernel pool". The SPICELIB routine FURNSH loads a kernel into the pool as shown below: FORTRAN: (SPICELIB) CALL FURNSH ( frame_kernel_name ) C: (CSPICE) furnsh_c ( frame_kernel_name ); IDL: (ICY) cspice_furnsh, frame_kernel_name MATLAB: (MICE) cspice_furnsh ( 'frame_kernel_name' ) PYTHON: (SPICEYPY)* furnsh( frame_kernel_name ) In order for a program or routine to extract data from the pool, the SPICELIB routines GDPOOL, GIPOOL, and GCPOOL are used. See [2] for more details. This file was created and may be updated with a text editor or word processor. * SPICEYPY is a non-official, community developed Python wrapper for the NAIF SPICE toolkit. Its development is managed on Github. It is available at: https://github.com/AndrewAnnex/SpiceyPy 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 MPO instrument ID code, constructed using the spacecraft ID number (-121) followed by the NAIF three digit ID number for one of the MERTIS data item. These IDs are as follows Instrument name ID -------------------- ------- MPO_MERTIS_PLANET -121201 MPO_MERTIS_PLANET_TIS -121211 MPO_MERTIS_PLANET_TIR -121221 MPO_MERTIS_SPACE -121202 MPO_MERTIS_SPACE_TIS -121212 MPO_MERTIS_SPACE_TIR -121222 The remainder of the name is an underscore character followed by the unique name of the data item. For example, the TIS boresight direction in the MPO_MERTIS_PLANET frame (see [2]) is specified by: INS-121211_BORESIGHT The upper bound on the length of the name of any data item identifier is 32 characters. If the same item is included in more than one file, or if the same item appears more than once within a single file, the latest value supersedes any earlier values. Overview --------------------------------------------------------------------------- From [5]: The Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) is an innovative instrument for studying the surface composition and mineralogy of planet Mercury. MERTIS combines an uncooled grating push broom IR-spectrometer (TIS) with a radiometer (TIR), which will operate in the wavelength region of 7-14 and 7-40 um, respectively. The spatial resolution of the MERTIS observations will be about 500 m globally and better than 500 m for approximately 5-10 percent of the surface. MERTIS has heritage from the Mars Express Planetary Fourier Spectrometer (PFS), the Visual and Thermal Imaging Spectro-meter (VIRTIS) for the Rosetta and Venus Express missions, and the Bispectral Infrared Detection (BIRD). Due to the integrated instrument approach of the proposed design, MERTIS-TIS and MERTIS-TIR share the same optics, instrument electronics and in-flight calibration components, similar to PFS on Mars Express. MERTIS features two channels, the spectrometric and the radiometric channel. Both channels are highly integrated and use the same entrance optics and the same calibration sources according an in-plane separation arrangement. The highly miniaturized radiometer is positioned at the slit of the spectrometer. Data is obtained in a push-broom mode. The radiometer has two channels of 15 thermopiles, one channel on each side of the slit. Filters placed directly on the thermopile arrays will select the range from 7-14 mico m for one channel and 7-40 micro m. While the first channel is used for cross calibration with the spectrometric channel, the latter will allow measurements of the surface temperature down to 100K with accuracy better than 1K. The spectrometric channel is an IR-imaging spectrometer based on the push-broom principle. It is based on an un-cooled micro-bolometer array providing spectral separation and spatial resolution according to its 2 dimensional shape. The operation concept principle for both channels is characterized by intermediate scanning of the planet surface and 3 different calibration targets - free space and on-board black body sources at 300K and 700K. The measurement of free space as a zero radiance reference allows determining the instrument energy. The black body sources will allow a radiometric calibration of both channels. The temperatures are selected to reflect the instrument temperature (~300K) and the temperature of the dayside of Mercury. The general instrument architecture comprises two functionally independent parts - the Sensor Head and the Electronics Unit. Due to the need for a high degree of miniaturisation the physical layout of these units are inseparable. The suite is completed by a pointing device which orients the optical path to incoming radiation sequentially from Mercury, free space and black body devices emitting at 300 and 700 K as calibration targets. Passing a highly reflective baffle in front of the instrument the IR radiation is guided via the pointing device through an IR-window to the entrance optics. This part ends up with a slit at the intermediate focus which is the interface to the spectrometer optics. Diffracted by a curved grating the beam is focused onto the bolometer. Within the Sensor Head all proximity electronics is contained. A critical issue is the thermal design of this unit because the changes in temperature will cause significant misinterpretation of the measurements. The following table summarizes the instrument optics, performances and resolution: Parameter | Units | Spectrometer | Radiometer ========================+============+=================+=================== Focal length | mm | 50 Focal number | | 2 Optical efficiency | | 0.540 ----------------------+------------+-----------------+----------------- Spectrometer detector | | Bolometer | Thermopile line | | array | array ----------------------+------------+-----------------+----------------- Detector physical | | 160 x 120 pix | 2 x 15 pix pixels | | @ 35 micro m | @ 250 micro m ----------------------+------------+-----------------+----------------- Detector illuminated | | 100 x 80 pix | 2 x 15 pix pixels | | @ 35 micro m | @ 250 micro m ----------------------+------------+-----------------+----------------- Spectral range | micro m | 7-14 | 7-40 ----------------------+------------+-----------------+----------------- Spectral Channel | nm/pixel | 90 | width | | | Line Array 1 | micro m | | 7-14 (filter) Line Array 2 | micro m | | 7-40 ----------------------+------------+-----------------+----------------- Spectral resolution / | nm | 78-156 | Spectral sampling | | | distance | | | ----------------------+------------+-----------------+----------------- Detectivity | | | D* | cm*Hz^0.5* | | 7*10^8 | Hz^(-1) | | NEP | pW | 15 | ----------------------+------------+-----------------+----------------- Field of view (FOV) | degrees | 4 x 0 | 4 x 1 ----------------------+------------+-----------------+----------------- Instantaneous FOV | mrad | 0.7 | ----------------------+------------+-----------------+----------------- Dwell time | | | Periherm 400km | ms | 109 | 775 Apoherm 1500km | ms | 784 | 5597 ----------------------+------------+-----------------+----------------- Swath Width | km | 28 Instrument dimension | mm^3 | 192 x 181 x 126 External baffles dim. | mm^3 | 200 x diam 73 & 85 x diam 75 Mass | kg | 3.3 Power Consumption | W | 7.2 - 13 (16W sensor head heated) Data Rate | KBit/s | 1-1263 Mounting Alignment --------------------------------------------------------------------------- Refer to the latest version of the BepiColombo Frames Definition Kernel (FK) [2] for the MERTIS reference frame definitions and mounting alignment information. Optical Parameters --------------------------------------------------------------------------- The following MERTIS TIR and TIS nominal first order optical parameters are included in the data section below: Parameter | Units | Value ========================+============+================= Focal length | mm | 50 ----------------------+------------+----------------- Focal number | | 2 ----------------------+------------+----------------- Optical efficiency | | 0.540 ----------------------+------------+----------------- Instantaneous FOV | mrad | 0.7 The keywords below provide nominal values from the table above. Angular size values in the keywords are given radians, with the cross-track size being the first value and the along-track size being the second value in each pair. \begindata INS-121210_FOCAL_LENGTH = ( 50.0 ) INS-121210_F/RATIO = ( 2.0 ) INS-121210_FOV_ANGULAR_SIZE = ( 0.069813, 0.000698 ) INS-121210_IFOV = ( 0.000700, 0.000700 ) INS-121211_FOCAL_LENGTH = ( 50.0 ) INS-121211_F/RATIO = ( 2.0 ) INS-121211_FOV_ANGULAR_SIZE = ( 0.069813, 0.000698 ) INS-121211_IFOV = ( 0.000700, 0.000700 ) INS-121212_FOCAL_LENGTH = ( 50.0 ) INS-121212_F/RATIO = ( 2.0 ) INS-121212_FOV_ANGULAR_SIZE = ( 0.069813, 0.000698 ) INS-121212_IFOV = ( 0.000700, 0.000700 ) INS-121220_FOCAL_LENGTH = ( 50.0 ) INS-121220_F/RATIO = ( 2.0 ) INS-121220_FOV_ANGULAR_SIZE = ( 0.069813, 0.017453 ) INS-121220_IFOV = ( 0.000700, 0.000700 ) INS-121221_FOCAL_LENGTH = ( 50.0 ) INS-121221_F/RATIO = ( 2.0 ) INS-121221_FOV_ANGULAR_SIZE = ( 0.069813, 0.017453 ) INS-121221_IFOV = ( 0.000700, 0.000700 ) INS-121222_FOCAL_LENGTH = ( 50.0 ) INS-121222_F/RATIO = ( 2.0 ) INS-121222_FOV_ANGULAR_SIZE = ( 0.069813, 0.017453 ) INS-121222_IFOV = ( 0.000700, 0.000700 ) \begintext Detector Parameters --------------------------------------------------------------------------- The nominal MERTIS detector parameters are: Spectrometer detector | | Bolometer | Thermopile line | | array | array ========================+============+==================================== Detector physical | | 160 x 120 pix | 2 x 15 pix pixels | | @ 35 micro m | @ 250 micro m ----------------------+------------+-----------------+----------------- Detector illuminated | | 100 x 80 pix | 2 x 15 pix pixels | | @ 35 micro m | @ 250 micro m ----------------------+------------+-----------------+----------------- Pixels projected on | | 100 x 1 pix | 2 x 15 pix the target (spectral | | @ 35 micro m | @ 250 micro m direction is splitted | | | inside the instrument)| | | ----------------------+------------+-----------------+----------------- Spectral range | micro m | 7-14 | 7-40 ----------------------+------------+-----------------+----------------- Spectral Channel | nm/pixel | 90 | width | | | Line Array 1 | micro m | | 7-14 (filter) Line Array 2 | micro m | | 7-40 ----------------------+------------+-----------------+----------------- Spectral resolution / | nm | 78-156 | Spectral sampling | | | distance | | | ----------------------+------------+-----------------+----------------- Detectivity | | | D* | cm*Hz^0.5* | | 7*10^8 | Hz^(-1) | | NEP | pW | 15 | and the values which are defined as SPICE data: parameter | TIS (Bolometer) | TIR (Thermopile) =================================+==================|==================== Detector Array Size/Physical | | Along-track | 1 | 2 Cross-track | 100 | 15 ------------------------------+------------------+-------------------- Detector Array Size/Spatial | | Along-track | 420 micro m | 50 micro m Cross-track | 560 micro m | 3640 micro m ------------------------------+------------------+-------------------- Detector Array Center/Spatial | | Along-track | 210 micro m | 25 micro m Cross-track | 280 micro m | 1820 micro m ------------------------------+------------------+-------------------- Pixel Size, microns/Spatial | | Cross-track | 35 | 1100 Along-track | 35 | 200 The values are given in microns for PIXEL_SIZE keywords and in counts for PIXEL_SAMPLES, PIXEL_LINES, and CENTER keywords. \begindata INS-121210_PIXEL_SIZE = ( 35, 35) INS-121210_PIXEL_SAMPLES = ( 1 ) INS-121210_PIXEL_LINES = ( 100 ) INS-121210_CCD_CENTER = ( 1, 50.0 ) INS-121211_PIXEL_SIZE = ( 35, 35) INS-121211_PIXEL_SAMPLES = ( 1 ) INS-121211_PIXEL_LINES = ( 100 ) INS-121211_CCD_CENTER = ( 1, 50.0 ) INS-121212_PIXEL_SIZE = ( 35, 35) INS-121212_PIXEL_SAMPLES = ( 1 ) INS-121212_PIXEL_LINES = ( 100 ) INS-121212_CCD_CENTER = ( 1, 50.0 ) INS-121220_PIXEL_SIZE = ( 1100.00, 200.00 ) INS-121220_PIXEL_SAMPLES = ( 2 ) INS-121220_PIXEL_LINES = ( 15 ) INS-121220_CCD_CENTER = ( 1, 7.5 ) INS-121221_PIXEL_SIZE = ( 1100.00, 200.00 ) INS-121221_PIXEL_SAMPLES = ( 2 ) INS-121221_PIXEL_LINES = ( 15 ) INS-121221_CCD_CENTER = ( 1, 7.5 ) INS-121222_PIXEL_SIZE = ( 1100.00, 200.00 ) INS-121222_PIXEL_SAMPLES = ( 2 ) INS-121222_PIXEL_LINES = ( 15 ) INS-121222_CCD_CENTER = ( 1, 7.5 ) \begintext FOV Definitions --------------------------------------------------------------------------- The following is a summary of the MERTIS fields of views: ----------------- ---------------- ---------------- Slit Horizontal Vertical ----------------- ---------------- ---------------- TIS 4.0 degrees 0.04 degrees TIR 4.0 degrees 1.0 degrees ----------------- ---------------- ---------------- where the horizontal direction lies along the spacecraft Y-axis and the vertical is along the spacecraft X-axis (from [8]). The rotating pointing mechanism in MERTIS allows the TIR field of view to be pointed at either the surface (PLANET), cold space (SPACE) or one of the 2 onboard calibration sources. MERTIS TIS FOV: ~~~~~~~~~~~~~~~ The rotating pointing mechanism in MERTIS allows the TIS field of view to be pointed at either the surface (PLANET), cold space (SPACE) or one of the 2 onboard calibration sources. The TIS slit creates a rectangular field of view with angular dimensions of 4.0 x 0.040107 degrees. The larger of the two angles extends along the S/C +Y axis for the planet view and along the S/C +X axis for the space view. ^ +Ymer (cross track) | ^ direction | | | of | 0.040107 degrees | | flight | | v Pixel 1 | Pixel 100 --- +---------|---------+ | 1 line | x-------------> +Xmer (across track) --- +-------------------+ ^ 100 pixels/line | | 4.0 degrees | |<----------------->| | | Boresight (+Z axis) is into the page The following diagrams illustrate the above field of view in the instrument frame: X Y mer mer ^ / ^ / | / | / | / | / | / | / Y | / o X | / o mer |/ 2.0 mer |/ 0.02 x--------> o--------> |\ Z |\ Z | \ ins | \ ins | \ | \ | \ | \ | \ | \ | \ | \ Plane X = 0 Plane Y = 0 The TIS FOV is nominaly defined with respect to the MPO_MERTIS reference frame. There are two additional auxiliary definitions to use the FOV in the MPO_MERTIS_PLANET and MPO_MERTIS_SPACE reference frames. Please note that the FOV reference and cross angles are defined with half angle values. The following FOV definition corresponds to the NAIF Body Names: MPO_MERTIS_TIS, MPO_MERTIS_TIS_PLANET and MPO_MERTIS_TIS_SPACE. \begindata INS-121210_NAME = 'MPO_MERTIS_TIS' INS-121210_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-121210_FOV_FRAME = 'MPO_MERTIS' INS-121210_FOV_SHAPE = 'RECTANGLE' INS-121210_FOV_CLASS_SPEC = 'ANGLES' INS-121210_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-121210_FOV_REF_ANGLE = ( 0.02 ) INS-121210_FOV_CROSS_ANGLE = ( 2.0 ) INS-121210_FOV_ANGLE_UNITS = 'DEGREES' INS-121211_NAME = 'MPO_MERTIS_TIS_PLANET' INS-121211_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-121211_FOV_FRAME = 'MPO_MERTIS_PLANET' INS-121211_FOV_SHAPE = 'RECTANGLE' INS-121211_FOV_CLASS_SPEC = 'ANGLES' INS-121211_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-121211_FOV_REF_ANGLE = ( 0.02 ) INS-121211_FOV_CROSS_ANGLE = ( 2.0 ) INS-121211_FOV_ANGLE_UNITS = 'DEGREES' INS-121212_NAME = 'MPO_MERTIS_TIS_SPACE' INS-121212_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-121212_FOV_FRAME = 'MPO_MERTIS_SPACE' INS-121212_FOV_SHAPE = 'RECTANGLE' INS-121212_FOV_CLASS_SPEC = 'ANGLES' INS-121212_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-121212_FOV_REF_ANGLE = ( 2.0 ) INS-121212_FOV_CROSS_ANGLE = ( 0.02 ) INS-121212_FOV_ANGLE_UNITS = 'DEGREES' \begintext MERTIS TIR FOV: ~~~~~~~~~~~~~~~ The TIR surface slit creates a rectangular field of view with angular dimensions of 4.0 x 1.0 degrees. The larger of the two angles extends along the S/C +Y axis for the planet view and along the S/C +X axis for the space view. ^ +Ymer (cross track) | ^ direction | | | of | 1.0 degree | | flight | | v Pixel 1 | Pixel 15 --- +---------|---------+ | 2 lines | x-------------> +Xmer (across track) --- +-------------------+ ^ 15 pixels/line | | 4.0 degrees | |<----------------->| | | Boresight (+Z axis) is into the page The following diagrams illustrate the above field of view in the instrument frame: X Y mer mer ^ / ^ / | / | / | / | / | / | / Y | / o X | / o mer |/ 2.0 mer |/ 0.5 x--------> o--------> |\ Z |\ Z | \ ins | \ ins | \ | \ | \ | \ | \ | \ | \ | \ Plane X = 0 Plane Y = 0 The TIR FOV is nominaly defined with respect to the MPO_MERTIS reference frame. There are two additional auxiliary definitions to use the FOV in the MPO_MERTIS_PLANET and MPO_MERTIS_SPACE reference frames. Please note that the FOV reference and cross angles are defined with half angle values. The following FOV definition corresponds to the NAIF Body Names: MPO_MERTIS_TIR, MPO_MERTIS_TIR_PLANET and MPO_MERTIS_TIR_SPACE. \begindata INS-121220_NAME = 'MPO_MERTIS_TIR' INS-121220_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-121220_FOV_FRAME = 'MPO_MERTIS' INS-121220_FOV_SHAPE = 'RECTANGLE' INS-121220_FOV_CLASS_SPEC = 'ANGLES' INS-121220_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-121220_FOV_REF_ANGLE = ( 0.5 ) INS-121220_FOV_CROSS_ANGLE = ( 2.0 ) INS-121220_FOV_ANGLE_UNITS = 'DEGREES' INS-121221_NAME = 'MPO_MERTIS_TIR_PLANET' INS-121221_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-121221_FOV_FRAME = 'MPO_MERTIS_PLANET' INS-121221_FOV_SHAPE = 'RECTANGLE' INS-121221_FOV_CLASS_SPEC = 'ANGLES' INS-121221_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-121221_FOV_REF_ANGLE = ( 0.5 ) INS-121221_FOV_CROSS_ANGLE = ( 2.0 ) INS-121221_FOV_ANGLE_UNITS = 'DEGREES' INS-121222_NAME = 'MPO_MERTIS_TIR_SPACE' INS-121222_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-121222_FOV_FRAME = 'MPO_MERTIS_SPACE' INS-121222_FOV_SHAPE = 'RECTANGLE' INS-121222_FOV_CLASS_SPEC = 'ANGLES' INS-121222_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-121222_FOV_REF_ANGLE = ( 2.0 ) INS-121222_FOV_CROSS_ANGLE = ( 0.5 ) INS-121222_FOV_ANGLE_UNITS = 'DEGREES' \begintext Optical Distortion -------------------------------------------------------- N/A. End of IK file.