KPL/IK NOMAD Instrument Kernel =============================================================================== This instrument kernel (I-kernel) contains the ExoMars-2016 Trace Gas Orbiter (TGO) Nadir and Occultation for MArs Discovery (NOMAD) instrument optics, detector and field-of-view (FOV) parameters definitions. Version and Date ------------------------------------------------------------------------------- Version 0.3 -- September 23, 2016 -- Marc Costa Sitja, ESAC/ESA Renamed the NOMAD LNO nadir and occultation field of view definitions (TGO_NOMAD_LNO_*) to NOMAD LNO nadir and occultation sience operations field of view definitions (TGO_NOMAD_LNO_OPS_*). Version 0.2 -- August 2, 2016 -- Marc Costa Sitja, ESAC/ESA Corrected FOV parameters for NOMAD LNO, SO and UVIS Spectometers. Corrected minor typos. Preliminary version. Pending review by the NOMAD instrument team. Version 0.1 -- May 24, 2016 -- Jorge Diaz del Rio, ODC Space Removed bad characters from the comments' area. Version 0.0 -- May 22, 2016 -- Jorge Diaz del Rio, ODC Space Preliminary version. Pending review by the TGO Science Operations and NOMAD instrument teams. 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. ``NOMAD spectrometer on the ExoMars trace gas orbiter mission: part 1 - design, manufacturing and testing of the infrared channels,'' Neefs, E. et al., Applied Optics Vol. 54, No. 28, 01-10-2015. 6. ``The NOMAD spectrometer on the ExoMars trace gas orbiter mission: part 2 - design and testing of the ultraviolet and visible channel,'' Patel, M. et al., Optics Express Vol.23, No. 23, 16-Nov-2015. 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 +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. 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. 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 NOMAD module. These IDs are defined in [4] as follows: Name NAIF ID --------------------- --------- TGO_NOMAD_LNO -143310 TGO_NOMAD_LNO_OPS_NAD -143311 TGO_NOMAD_LNO_OPS_OCC -143312 TGO_NOMAD_SO -143320 TGO_NOMAD_UVIS_NAD -143331 TGO_NOMAD_UVIS_OCC -143332 The remainder of the keyword name is an underscore character followed by the unique name of the data item. For example, the SO spectrometer boresight direction in the TGO_NOMAD_SO frame is specified by: INS-143320_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 ------------------------------------------------------------------------------- NOMAD consists of three separate channels, solar occultation (SO), limb nadir and occultation (LNO), and ultraviolet and visible spectrometer (UVIS), all controlled via a single main electronics interface (see [5]). NOMAD has two nadir lines of sight (one in the LNO and one in the UVIS channel) that are parallel to the spacecraft -Y axis, which nominally is always pointing towards and perpendicular to the surface of Mars. Therefore, NOMAD's nadir viewports are always directed to Mars. The orbital configuration of TGO fixes the angle between its -Y axis and the direction of the Martian limb to 67.07 degrees away from the -Y axis in the -Y/-X plane. NOMAD's three solar lines of sight (one in each of the channels) will be parallel to this limb direction, and hence form an angle of 67.07 degrees with the nadir lines of sight. To perform SO measurements, the spacecraft will need to yaw rotate around its Y axis twice per orbit, once during the day, once during the night, so that, well before sunrise or sunset, the solar lines of sight point to the limb. During SOs the spacecraft will adopt an inertial pointing mode, fixed on the center of the Sun, resulting in an apparent ingress into or egress from the Martian disk. Solar Occultation Channel ------------------------- The Solar Occultation (SO) Channel is based on the principle of combining an AOTF as an order sorter and an echelle grating spectrometer. The spectral observation band covers the 2.3 to 4.3 microns range, the instrument line profile (ILP) is 0.22 cm-1 full width at half-maximum (FWHM) or better over the whole spectral range, to be sampled by at least two detector pixels. The instrument is optimized close to 3000 cm-1, resulting in an ILP of 0.15 cm-1 FWHM at 3.3 microns. The FOV of the SO channel is driven by the fact that it has to observe solely during SO. This FOV has a spatial dimension of 30 arcmin. It is required that all the detector lines illuminated by the solar disk can be downloaded to Earth. Perpendicular to the spatial direction a FOV of 2 arcmin is maintained resulting in sufficient height resolution while vertically scanning through the Martian atmosphere (vertical sampling less than 1 km). From dimensional constraints it follows that the entrance aperture diameter of the SO channel shall be at maximum 20 mm. SO has a SNR greater than 900 over the complete spectral range, measured over a zone of 200 detector columns centered on the column with the maximum signal, for a minimum solar signal (i.e., at maximum Mars-Sun distance) and including all instrument sources of noise. Table #1 gives an overview of the characteristics of the SO channel. Table 1: SO and LNO channel parameters ----------------------------------------------------- Parameter SO LNO --------------------- ------------- ------------ Wavelength, microns 2.3 - 4.3 2.3 - 3.8 Wavenumber, cm-1 4250 - 2320 4250 - 2630 ILP, cm-1 0.22 0.5 ILP for CH4, cm-1 0.15 Resolving power 20,000 10,000 FoV, arcmin. 30.0x2.0 150.0x4.0 Spatial sampling, 1 1 arcmin. SRN >= 900 >= 400 ----------------------------------------------------- Limb, Nadir and Occultation Channel ------------------------------------ The Limb, Nadir and Occultation (LNO) Channel has a SNR of greater than 400 over the complete spectral domain, after binning of all detector rows by column, measured over a zone of 200 columns centered on the column with the maximum signal, for a minimum solar signal (i.e., at maximum Mars-Sun distance), and including all instrument sources of noise. In the region that contains the methane absorption line, LNO has an SNR of greater than 1000. As a price to pay for the challenging SNR specification, the wavelength range (between 2.3 and 3.8 microns) and ILP (0.5 cm-1, sampled by at least two pixels) are reduced in comparison with SO. While defining an appropriate instantaneous FOV for the LNO channel, a compromise had to be found between the channel performance in SO (vertical sampling) and in nadir mode (SNR, footprint). LNO has a FOV of 150 x 4 arc minutes. Since LNO uses this FOV also for solar occultions, the vertical sampling capacity of LNO is reduced by a factor of 2 compared to the SO channel. The entrance aperture diameter of the LNO channel is nearly 30 mm, which is greater than that of the SO channel, to provide higher signal input. Table #1 gives an overview of the characteristics of the LNO channel. Ultraviolet and Visible Channel ------------------------------- The Ultraviolet and Visible (UVIS) Channel UVIS operates in the wavelength domain between 200 and 650 nm. The spectrometer has two telescopes, one for each viewing channel. The spectrometer is based on the conventional Czerny-Turner configuration. The main components are the entrance slit, the aperture, the collimating mirror, the diffraction grating, the focusing mirror, the 2nd order filter and the detector CCD. The light is delivered by an optical fibre. The spectrometer configuration combines simplicity and high-performances. In particular, the spectral range is very broad (200-650nm) with optimized performance in the UV range. Blaze angle and incidence angle achieve the highest reflectance of the first diffraction order at 220nm. The 2nd order filter solves the issue of the overlap between the 1st diffraction order and the 2nd diffraction order of the grating. Indeed, due to the wide spectral range of the observed signal, first diffraction order rays and second diffraction order rays overlap on the detector. Hence a long-pass filter has been placed in front of the detector to block the second order contribution. The cutoff is chosen at 340nm. The filter is a window partially coated. The 2nd order signal goes through a coated area. As such the 2nd order signal is completed blocked as long as the signal at wavelength shorter than the wavelength corresponding to the uncoated-coated transition of the filter. The slit width is 65 microns which corresponds to a resolution better than 1.5nm. This width results from a trade-off between resolution and the SNR. Table #2 summarizes the characteristics of the UVIS channel. Table 2: UVIS ``nadir'' and ``solar occultation'' channel parameters ------------------------------------------------------------------- Parameter Solar Occultation Nadir -------------------------- ------------------- ---------------- Spectral range, nm 200-650 200-650 Spectral resolution,nm 1.5 1.5 Numerical aperture fibre 0.22 0.22 F-number 2.15 2.18 FOV, arcminutes 2 43 Binning, rows 8 64 Observation time, s 0.2 15 ------------------------------------------------------------------- Each telescope includes a single parabolic mirror for space and weight minimization. Light is focused on a single fibre and a bundle of fibres for the solar occultation channel and the nadir channel respectively. The field of views (2 arcmin for solar occultation and 43 arcmin for nadir) are determined by the focal length of the mirror and the entrance aperture of the fibre(s). UVIS has one periscope in front of the solar telescope with a mirror allowing the pointing towards the Sun and a cut out hole in the NOMAD cover for the nadir viewing telescope. UVIS switches between nadir and solar viewing angles by alternating which optic fibre cable is placed at the input of the spectrometer. The selector mechanism is a rotating motor mechanism that moves the fibres in front of the slit. Fibre positioning is accurately defined by two hard stops. Mounting Alignment ------------------------------------------------------------------------------- Refer to the latest version of the ExoMars-2016 Frames Definition Kernel (FK) [4] for the NOMAD reference frame definitions and mounting alignment information. NOMAD LNO Spectrometer Field-of-View Layouts --------------------------------------------------------------------------- This diagram illustrates the NOMAD LNO apparent FOV layout in the TGO_NOMAD_LNO reference frame, providing a reference to the TGO_SPACECRAFT frame when the LNO flip mirror is in the "nadir position". ^ +Zsc | | | x--------> +Ysc +Xsc ^ +Ylno | | | | v .------------------------|------------------------. ----- | o---------> | 4.00 arcmin '------------------------------ +Xlno ------------' ----- ^ | | | |<----------------------------------------------->| | 150.0 arcmin | +Zlno is out of the page; +Ysc is into the page. The apparent FOV layouts in the TGO_NOMAD_LNO_OPS_NAD and TGO_NOMAD_LNO_OPS_OCC reference frames are exactly the same. For the alignment of the TGO_NOMAD_LNO_OPS_NAD and TGO_NOMAD_LNO_OPS_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 -143310 (TGO_NOMAD_LNO), -143311 (TGO_NOMAD_LNO_OPS_NAD) and -143312 (TGO_NOMAD_LNO_OPS_OCC). NOMAD SO Spectrometer Field-of-View Layout --------------------------------------------------------------------------- This diagram illustrates the NOMAD SO apparent FOV layout in the TGO_NOMAD_SO reference frame. ^ +Yso | | | | v .------------------------|------------------------. ----- | o---------> | 2.00 arcmin '------------------------------ +Xso -------------' ----- ^ | | 30.00 arcmin | |<----------------------------------------------->| +Zso is out of the page. Note that the +Zso (NOMAD SO boresight) is pointing at ~67.07 degrees from -Y s/c axis towards -X s/c axis in the XY plane. The +Xso is aligned to the +X spacecraft axis. For the alignment of the TGO_NOMAD_SO frame with respect to the TGO_SPACECRAFT frame, pelase refer to [4]. This FOV is associated to instrument ID -143320 (TGO_NOMAD_SO) NOMAD UVIS Spectrometer Field-of-View Layout --------------------------------------------------------------------------- This diagram illustrates the NOMAD UVIS apparent FOV layout in the TGO_NOMAD_UVIS_NAD and TGO_NOMAD_UVIS_OCC reference frames. | | ^ V | +Yuvis* ------------- . | . (NAD) 43.0 arcmin / | \ | o--------> (OCC) 2.0 arcmin \ / +Xuvis* ------------- ` - ' ^ | +Zuvis* is out of the | page; * refers to _NAD and _OCC For the alignment of the TGO_NOMAD_UVIS_NAD and TGO_NOMAD_UVIS_OCC frames with respect to the TGO_SPACECRAFT frame and with respect to each other, please refer to [4]. These FOVs are associated to instrument IDs -143331 (TGO_NOMAD_UVIS_NAD) and -143332 (TGO_NOMAD_UVIS_OCC), respectively. FOV Definition --------------------------------------------------------------------------- This section contains assignments defining the NOMAD LNO, SO and UVIS FOVs. These definitions are based on the NOMAD spectrometers parameters provided in the previous sections and are provided in a format consistent with/required by the SPICE TOOLKIT function GETFOV. NOMAD Limb, Nadir and Occultation Channel (TGO_NOMAD_LNO*) FoVs: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The LNO FOV is defined as a rectangular pyramid with a full angle of 150x4 arc-minutes. It is defined with respect to the TGO_NOMAD_LNO_OPS_NAD and TGO_NOMAD_LNO_OPS_OCC frames for nadir and solar occultation observations (see [5]). In addition a third FoV definition is provided for using the LNO Field-of-View together with the TGO_NOMAD_LNO 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-143310_FOV_FRAME = 'TGO_NOMAD_LNO' INS-143310_FOV_SHAPE = 'RECTANGLE' INS-143310_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-143310_FOV_CLASS_SPEC = 'ANGLES' INS-143310_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-143310_FOV_REF_ANGLE = ( 75.000000 ) INS-143310_FOV_CROSS_ANGLE = ( 2.000000 ) INS-143310_FOV_ANGLE_UNITS = 'ARCMINUTES' INS-143311_FOV_FRAME = 'TGO_NOMAD_LNO_OPS_NAD' INS-143311_FOV_SHAPE = 'RECTANGLE' INS-143311_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-143311_FOV_CLASS_SPEC = 'ANGLES' INS-143311_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-143311_FOV_REF_ANGLE = ( 75.000000 ) INS-143311_FOV_CROSS_ANGLE = ( 2.000000 ) INS-143311_FOV_ANGLE_UNITS = 'ARCMINUTES' INS-143312_FOV_FRAME = 'TGO_NOMAD_LNO_OPS_OCC' INS-143312_FOV_SHAPE = 'RECTANGLE' INS-143312_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-143312_FOV_CLASS_SPEC = 'ANGLES' INS-143312_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-143312_FOV_REF_ANGLE = ( 75.000000 ) INS-143312_FOV_CROSS_ANGLE = ( 2.000000 ) INS-143312_FOV_ANGLE_UNITS = 'ARCMINUTES' \begintext NOMAD Solar Occultation Channel (TGO_NOMAD_SO) FoV: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The SO FOV is defined as a rectangular pyramid with a full angle of 30x2 arc-minutes. It is defined with respect to the TGO_NOMAD_SO 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-143320_FOV_FRAME = 'TGO_NOMAD_SO' INS-143320_FOV_SHAPE = 'RECTANGLE' INS-143320_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-143320_FOV_CLASS_SPEC = 'ANGLES' INS-143320_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-143320_FOV_REF_ANGLE = ( 15.000000 ) INS-143320_FOV_CROSS_ANGLE = ( 1.000000 ) INS-143320_FOV_ANGLE_UNITS = 'ARCMINUTES' \begintext NOMAD Ultraviolet and Visible Channel (TGO_NOMAD_UVIS*) FoV: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The UVIS ``Nadir'' FOV is defined as a cone with a full angle of 43.0 arc-minutes and the ``occultation'' FOV as a cone with a full angle of 2.0 arc-minutes. They are defined with respect to the TGO_NOMAD_UVIS_NAD and TGO_NOMAD_UVIS_OCC frames respectively. 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-143331_FOV_FRAME = 'TGO_NOMAD_UVIS_NAD' INS-143331_FOV_SHAPE = 'CIRCLE' INS-143331_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-143331_FOV_CLASS_SPEC = 'ANGLES' INS-143331_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-143331_FOV_REF_ANGLE = ( 21.50000 ) INS-143331_FOV_ANGLE_UNITS = 'ARCMINUTES' INS-143332_FOV_FRAME = 'TGO_NOMAD_UVIS_OCC' INS-143332_FOV_SHAPE = 'CIRCLE' INS-143332_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-143332_FOV_CLASS_SPEC = 'ANGLES' INS-143332_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-143332_FOV_REF_ANGLE = ( 1.00000 ) INS-143332_FOV_ANGLE_UNITS = 'ARCMINUTES' \begintext Optical Distortion -------------------------------------------------------- [TBD] Platform ID --------------------------------------------------------------------------- This number is the NAIF instrument ID of the platform on which the instrument mounted. For all NOMAD components it is the spacecraft. \begindata INS-143310_PLATFORM_ID = ( -143000 ) INS-143311_PLATFORM_ID = ( -143000 ) INS-143312_PLATFORM_ID = ( -143000 ) INS-143320_PLATFORM_ID = ( -143000 ) INS-143331_PLATFORM_ID = ( -143000 ) INS-143332_PLATFORM_ID = ( -143000 ) \begintext End of IK file.