KPL/IK ACS Instrument Kernel =============================================================================== This instrument kernel (I-kernel) contains the ExoMars-2016 Trace Gas Orbiter (TGO) Atmospheric Chemistry Suite (ACS) spectroscopic instruments and sensors optics, detectors and field-of-view (FOV) parameters. Version and Date ------------------------------------------------------------------------------- Version 0.4 -- September 26, 2016 -- Marc Costa Sitja, ESAC/ESA Corrected FOV parameters for TIRVIM. Preliminary version. Pending review by Anton Ledkov and the ACS instrument team. Version 0.3 -- September 8, 2016 -- Marc Costa Sitja, ESAC/ESA Corrected minor typos and text description. Version 0.2 -- August 2, 2016 -- Marc Costa Sitja, ESAC/ESA Corrected FOV parameters for ACS NIR, TIR and TIRVIM Spectometers Corrected minor typos and text description. Added Reference [7]. Version 0.1 -- May 22, 2016 -- Jorge Diaz del Rio, ODC Space Preliminary version. Version 0.0 -- September 17, 2014 -- Anton Ledkov, IKI Initial Release. References ------------------------------------------------------------------------------- 1. ``Frames Required Reading'' 2. ``Kernel Pool Required Reading'' 3. ``C-kernel Required Reading'' 4. ExoMars-2016 Frames Definition Kernel (FK), latest version. 5. ``Atmospheric Chemistry Suite (ACS): a Set of Infrared Spectrometers for Atmospheric Measurements onboard ExoMars Trace Gas Orbiter'', A. Trokhimovskiy et al. 6. ``High Resolution Middle Infrared Spectrometer, a Part of Atmospheric Chemistry Suite (ACS) for ExoMars 2016 Trace Gas Orbiter,'' International Conference on Space Optics, Tenerife 7-10 October 2014 7. Email from Alexander Trokhimovskiy ``Re: [EM16-SOC] [TGO] [SGS] [EM16.ACS] [EM16.NOMAD] SPICE review and misalignment update by 25th July'' on 8 August 2016. Contact Information ------------------------------------------------------------------------------- If you have any questions regarding this file contact SPICE support at ESAC: Marc Costa Sitja (+34) 91-8131-457 mcosta@sciops.esa.int, esa_spice@sciops.esa.int or SPICE support at IKI: Anton Ledkov +7 (495) 333-12-66 aledkov@rssi.ru or NAIF at JPL: Boris Semenov (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. The SPICE routine FURNSH loads a kernel file into the pool as shown below. CALL FURNSH ( 'frame_kernel_name' ) -- FORTRAN furnsh_c ( "frame_kernel_name" ); -- C cspice_furnsh, frame_kernel_name -- IDL cspice_furnsh( 'frame_kernel_name' ) -- MATLAB 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''. Once the file has been loaded, the SPICE routine GETFOV (getfov_c in C, cspice_getfov in IDL and MATLAB) can be used to retrieve FOV parameters for a given instrument or structure. The application program may obtain the value(s) for any other IK data item using the SPICELIB routines GDPOOL, GIPOOL, GCPOOL (gdpool_c, gipool_c, gcpool_c in C, cspice_gdpool, cspice_gipool, cspice_gcpool in IDL and MATLAB). See [2] for details. This file was created with, and can be updated with a text editor or word processor. Naming Conventions and Conventions for Specifying Data ------------------------------------------------------------------------------- Data items are specified using ``keyword=value'' assignments [2]. All keywords referencing values in this I-kernel start with the characters `INS' followed by the NAIF TGO instrument ID code, constructed using the spacecraft ID number (-143) followed by the NAIF three digit ID number for ACS module. These IDs are defined in [4] as follows: Name NAIF ID --------------------- --------- TGO_ACS_NIR_NAD -143111 TGO_ACS_NIR_OCC -143112 TGO_ACS_MIR -143120 TGO_ACS_TIRVIM -143130 TGO_ACS_TIRVIM_SPC -143131 TGO_ACS_TIRVIM_NAD -143132 TGO_ACS_TIRVIM_OCC -143133 The remainder of the keyword name is an underscore character followed by the unique name of the data item. For example, the MIR spectrometer boresight direction in the TGO_ACS_MIR frame is specified by: INS-143120_BORESIGHT The upper bound on the length of the name of any data item 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. Instrument Description ------------------------------------------------------------------------------- ACS includes three separate spectrometers, sharing common mechanical, thermal and electrical interfaces (see [5]). On the TGO spacecraft the instrument occupies the slot at the upper deck. ACS has several optical openings allowing observations in nadir (-Y in the spacecraft coordinate system), and in solar occultation, at ~67.07 degrees from -Y to -X in the XY plane, and possibly on the limb (using nadir apertures). These threes spectrometers are the Near-Infrared Spectrometer (NIR), the High Resolution Middle Infrared Spectrometer (MIR) and the Thermal Infrared V-shape Interferometer Mounting Spectrometer (TIRVIM). Near-Infrared Spectrometer (NIR): --------------------------------- The ACS NIR channel is a combination of an echelle spectrometer and an acousto-optic tunable filter (AOTF) for the selection of diffraction orders. ACS NIR is capable to perform nadir and occultation observations in the 0.7-1.6 microns spectral range with R greater than 20,000 resolution. A red filter at the entrance right after the periscope mirror cancels out all intense sun wavelengths shorter than 0.7 microns. AOTF-telescope assembling with improved energy transmission and implemented slit form the FOV of approximately 2x0.02 degrees. The echelle spectrometer employs the Littrow auto-collimation scheme, in which an off-axis parabolic mirror plays the role of the collimating and the imaging elements. To enhance the sensitivity the spectrometer uses a higher slit in combination with 2D array detector allowing to capture the flux of the dispersed light along the full dimension of the slit. The detector is based on a TE-cooled InGaAs array of 640x512 pixels. The spectral range is extended with respect to the standard InGaAs, and consists 0.4-1.7 microns. The detector's lines are averaged onboard into 5 bands of programmable position and height, each of 640 pixels long. The instrument can be programmed to register sequentially up to ten diffraction orders (10 different AOTF tunings, i.e. acoustic frequencies). The exposure time can be tuned from 1 ms to 1s depending on a observation regime. An onboard image averaging from 1 to 256 is also employed. For our custom size echelle grating (blaze angle 70 degrees, 24.35 grooves/mm, useful area of 46x102 mm2) and following Nyqvist sampling (2 pixels per resolution element), the resolving power of the aberration-free spectrometer could reach almost R = 30,000. The aberrations of the off-axis parabolic collimator reduce the resolving power to R greater than 20,000, optimized at 1.2 microns. High Resolution Middle Infrared Spectrometer (MIR): --------------------------------------------------- The MIR channel is a cross-dispersion spectrometer working in 2.3-4.2 microns spectral range, covering simultaneously up to 300 nm per measurement. A cross-dispersion concept on echelle and ordinary diffraction grating allows acquisition of the wide wavelength domain at once. That provides a strategic advantage for maximizing the number of gaseous species detected simultaneously. Moving the second grating allows to switch from one group of the diffraction orders to another prior to a series of measurements, or alternating two desired positions during one measurement sequence. Targeting very high spectral resolution the MIR channel operates in solar occultation only. A telescope with relative aperture of 1:3 forms the image of the solar disk on the slit. The FOV is determined by the slit and it consists 0.5x10 arc min (0.1x2.9 mrad). The spectral resolution of the spectrometer is fully slit-limited, and with a 30 microns slit the resolving power of lambda/delta-lambda greater than 50000 at 3.3 microns is supported. Two secondary cross-dispersion diffraction gratings (plain, 150 and 300 grooves per mm) are mounted back-to-back on a stepper motor to change observed echelle orders. Two secondary gratings are used depending on the long or short wavelength range being measured. Changing the position of the secondary grating in angular steps of 1.8 degrees, from 10 to 30 echelle orders are available for simultaneous record depending on the wavelength. 100 steps are evidently used to switch between gratings prior measurements. The full spectral range is covered on 107 diffraction orders, from 142 to 248. For each observation detector area is covered by 10 to 30 stripes, each corresponding to single echelle diffraction order. The height of the stripes ranges from 150 to 200 microns depending on the wavelength. It is planned that there will be a possibility to change the position of the stepper motor during the occultation measurements, and to register two adjacent groups of diffraction orders. The detector is a space-grade version of the standard Scorpio MW K508 Sofradir product, with optimized spectral range. This detector includes a 640x512 MWIR retina made of a MCT (Mecury Cadmium Telluride, HgCdTe) hybridized onto a silicon ROIC (read-out integrated circuit) by indium bumps. The pixel pitch is 15x15 microns. Given the complexity of the diffraction orders pattern, full detector frames will be transmitted to the ground, with lossless compression. However, similarly to NIR, the onboard averaging is possible. Single data frame will be accumulated for each 0.5 or 1 second, stacking of a number of shorter exposures. Thermal Infrared V-shape Interferometer Mounting Spectrometer (TIRVIM): ----------------------------------------------------------------------- TIRVIM is a 2-inch double pendulum Fourier-transform spectrometer covering in one interferometric channel the spectral range of 1.7-17 microns. The whole spectral range is covered in one channel with KBr beamsplitter. The maximal optical path difference (OPD) is 6 cm, allowing to reach apodized spectral resolution of 0.2 cm-1, and two PV-MCT detectors (one for 1.7-17 microns, the other for 1.7-4.5 microns), cooled by one Stirling-machine, thus increasing the sensitivity of the instrument by a factor of 50-80. The third detector, the pyroelectric one, will work at RT in 1.7-25 microns range and serve as a redundant channel. All detectors can operate for both Sun occultations and nadir measurements. For Sun observations with MCT detectors there is a special optical inlet ("periscope"), pointed at Sun. For nadir measurements TIRVIM has a single-axis pointer (scanner). The optical scheme of TIRVIM consists of the following main parts: Sun periscope, Scanner, blackbody simulator, interferometer, detector units with focusing optics and proximity electronics. The reference channel is based on 760-nm DFB Laser Diode. Scanner allows to point optical axis to nadir, to the Sun, to the internal blackbody and to the open space to obtain absolute radiometric calibration. On-board FFT and scissor mode for spectra will be implemented. Mounting Alignment ------------------------------------------------------------------------------- Refer to the latest version of the ExoMars-2016 Frames Definition Kernel (FK) [4] for the ACS reference frame definitions and mounting alignment information. ACS NIR Spectrometer Field-of-View Layouts --------------------------------------------------------------------------- This diagram illustrates the ACS NIR apparent FOV layout in the TGO_ACS_NIR_NAD reference frame, providing a reference to the TGO_SPACECRAFT frame. +Ysc x--------> | +Zsc | | v ^ +Yacs_nir* +Xsc | | | (0,0 | (639,0) v .------------------------|------------------------. ----- | o---------> | 0.02 deg '------------------------------ +Xacs_nir* -------' ----- (0,1) (639,1) ^ | | | |<----------------------------------------------->| | 2 deg | +Zacs_nir* is out of the page; +Ysc is into the page. The apparent FOV layout in the TGO_ACS_NIR_OCC reference frame is exactly the same. For the alignment of the TGO_ACS_NIR_NAD and TGO_ACS_NIR_OCC frames with respect to the TGO_SPACECRAFT frame and with respect to each other, please refer to [4]. This FOV is associated to instrument IDs -143111 (TGO_ACS_NIR_NAD) and -143112 (TGO_ACS_NIR_OCC). ACS MIR Spectrometer Field-of-View Layout --------------------------------------------------------------------------- This diagram illustrates the ACS MIR apparent FOV layout in the TGO_ACS_MIR reference frame. ^ +Yacs_mir | | | | (639,0) v .------------------------|------------------------. ----- | o---------> | 0.02 deg '------------------------------ +Xacs_mir --------' ----- (0,1) (639,1) ^ | | 0.23 deg | |<----------------------------------------------->| +Zacs_mir is out of the page. Note that the +Zacs_mir (ACS MIR boresight) is pointing at ~67.07 degrees from -Y s/c axis towards -X s/c axis in the XY plane. The +Xacs_mir is aligned to the +X spacecraft axis. For the alignment of the TGO_ACS_MIR frame with respect to the TGO_SPACECRAFT frame, pelase refer to [4]. This FOV is associated to instrument ID -143120 (TGO_ACS_MIR) ACS TIRVIM Spectrometer Field-of-View Layout --------------------------------------------------------------------------- This diagram illustrates the ACS TIRVIM apparent FOV layout in the TGO_ACS_TIRVIM reference frame, providing a reference to the TGO_SPACECRAFT frame when the TIRVIM scanning mirror is in the "zero position" as defiened in [7]. This FOV is associated to instrument IDs -143130 (TGO_ACS_TIRVIM), -143131 (TGO_ACS_TIRVIM_SPC), -143132 (TGO_ACS_TIRVIM_NAD) and -143133 (TGO_ACS_TIRVIM_OCC). +Ysc x-------> | +Zsc ^ | | +Yacs_tirvim | ------------- . | . v ^ / | \ +Xsc 2.0 degrees | o--------> v \ / +Xacs_tirvim ------------- ` - ' +Zacs_tirvim is out of the page; +Ysc is into the page. For the alignment of the TGO_ACS_TIRVIM_NAD, TGO_ACS_TIRVIM_OCC and TGO_ACS_TIRVIM_SPC frames with respect to the TGO_SPACECRAFT frame and with respect to each other, please refer to [4]. ACS Spectrometers Spectral Parameters --------------------------------------------------------------------------- This section contains assignments specifying ACS spectral resolution parameters. The following ACS spectral resolution parameters are included in the data section below, taken from [5] (nominal values): ----------------------------------------------------------------- parameter NIR MIR TIRVIM ----------------------------------------------------------------- Spectral range, microns nominal 0.73 - 1.6 2.3 - 4.3 1.7 - 17 ----------------------------------------------------------------- These values are provided in the assignments below, with the same units as in the table. \begindata INS-143111_SPECTRAL_RANGE = ( 0.73, 1.6 ) INS-143112_SPECTRAL_RANGE = ( 0.73, 1.6 ) INS-143120_SPECTRAL_RANGE = ( 2.3, 4.3 ) INS-143130_SPECTRAL_RANGE = ( 1.7, 17 ) \begintext FOV Definition --------------------------------------------------------------------------- This section contains assignments defining the ACS NIR, MIR and TIRVIM FOVs. These definitions are based on the ACS spectrometer parameters provided in the previous sections and are provided in a format consistent with/required by the SPICE TOOLKIT function GETFOV. ACS Near Infrared Spectrometer (TGO_ACS_NIR*) FoVs: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The NIR FOV is defined as a rectangular pyramid with a full angle of 20x0.02 arcmin. It is defined with respect to the TGO_ACS_NIR_NAD and TGO_ACS_NIR_OCC frames for nadir and solar occultation observations (see [5] and [6]). The boresight and the cross-reference vectors are unit along the +Z axis and the +X axis of the frame(s), respectively. Please note that the FOV reference and cross angles are defined with half angle values. \begindata INS-143111_FOV_FRAME = 'TGO_ACS_NIR_NAD' INS-143111_FOV_SHAPE = 'RECTANGLE' INS-143111_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-143111_FOV_CLASS_SPEC = 'ANGLES' INS-143111_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-143111_FOV_REF_ANGLE = ( 1.00 ) INS-143111_FOV_CROSS_ANGLE = ( 0.01 ) INS-143111_FOV_ANGLE_UNITS = 'DEGREES' INS-143112_FOV_FRAME = 'TGO_ACS_NIR_OCC' INS-143112_FOV_SHAPE = 'RECTANGLE' INS-143112_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-143112_FOV_CLASS_SPEC = 'ANGLES' INS-143112_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-143112_FOV_REF_ANGLE = ( 1.00 ) INS-143112_FOV_CROSS_ANGLE = ( 0.01 ) INS-143112_FOV_ANGLE_UNITS = 'DEGREES' \begintext ACS High Resolution Middle Infrared Spectrometer (TGO_ACS_MIR) FoV: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The MIR FOV is defined as a rectangular pyramid with a half angle of 0.23x0.02 degrees. It is defined with respect to the TGO_ACS_MIR frame (see [5]). The boresight and the cross-reference vectors are unit along the +Z axis and the +X axis of the frame, respectively. Please note that the FOV reference and cross angles are defined with half angle values. \begindata INS-143120_FOV_FRAME = 'TGO_ACS_MIR' INS-143120_FOV_SHAPE = 'RECTANGLE' INS-143120_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-143120_FOV_CLASS_SPEC = 'ANGLES' INS-143120_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-143120_FOV_REF_ANGLE = ( 0.115 ) INS-143120_FOV_CROSS_ANGLE = ( 0.010 ) INS-143120_FOV_ANGLE_UNITS = 'DEGREES' \begintext ACS Thermal Infrared V-shape Interferometer Mounting (TGO_ACS_TIRVIM*) FoV: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The TIRVIM FOV is defined as a cone with a full angle of 2.0 degrees. It is defined with respect to the TGO_ACS_TIRVIM frame but could also be used with the TGO_ACS_TIRVIM_NAD, TGO_ACS_TIRVIM_OCC and TGO_ACS_TIRVIM_SPC frames specified for nadir, solar occultation and cold space observations (see [5] and [6]). In addition a fourth FoV definition is provided for using the TIRVIM Field-of-View together with the TGO_ACS_TIRVIM CK-based instrument frame. The boresight and the cross-reference vectors are unit along the +Z axis and the +X axis of the frame(s), respectively. Please note that the FOV reference and cross angles are defined with half angle values. \begindata INS-143130_FOV_FRAME = 'TGO_ACS_TIRVIM' INS-143130_FOV_SHAPE = 'CIRCLE' INS-143130_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-143130_FOV_CLASS_SPEC = 'ANGLES' INS-143130_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-143130_FOV_REF_ANGLE = ( 1.00000 ) INS-143130_FOV_ANGLE_UNITS = 'DEGREES' INS-143131_FOV_FRAME = 'TGO_ACS_TIRVIM_SPC' INS-143131_FOV_SHAPE = 'CIRCLE' INS-143131_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-143131_FOV_CLASS_SPEC = 'ANGLES' INS-143131_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-143131_FOV_REF_ANGLE = ( 1.00000 ) INS-143131_FOV_ANGLE_UNITS = 'DEGREES' INS-143132_FOV_FRAME = 'TGO_ACS_TIRVIM_NAD' INS-143132_FOV_SHAPE = 'CIRCLE' INS-143132_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-143132_FOV_CLASS_SPEC = 'ANGLES' INS-143132_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-143132_FOV_REF_ANGLE = ( 1.00000 ) INS-143132_FOV_ANGLE_UNITS = 'DEGREES' INS-143133_FOV_FRAME = 'TGO_ACS_TIRVIM_OCC' INS-143133_FOV_SHAPE = 'CIRCLE' INS-143133_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-143133_FOV_CLASS_SPEC = 'ANGLES' INS-143133_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-143133_FOV_REF_ANGLE = ( 1.00000 ) INS-143133_FOV_ANGLE_UNITS = 'DEGREES' \begintext Optical Distortion -------------------------------------------------------- [TBD] Platform ID --------------------------------------------------------------------------- This number is the NAIF instrument ID of the platform on which the instrument mounted. For all ACS components it is the spacecraft. \begindata INS-143111_PLATFORM_ID = ( -143000 ) INS-143112_PLATFORM_ID = ( -143000 ) INS-143120_PLATFORM_ID = ( -143000 ) INS-143130_PLATFORM_ID = ( -143000 ) INS-143131_PLATFORM_ID = ( -143000 ) INS-143132_PLATFORM_ID = ( -143000 ) INS-143133_PLATFORM_ID = ( -143000 ) \begintext End of IK file.