KPL/IK MAJIS Instrument Kernel =============================================================================== This instrument kernel (I-kernel) contains the JUICE Moons And Jupiter Imaging Spectrometer (MAJIS) instrument optics, detector and field-of-view (FOV) paramters. Version and Date ------------------------------------------------------------------------------- Version 0.2 -- May 11, 2016 -- Jorge Diaz del Rio, ODC Space Corrected typos in text. Preliminary version. Pending review by the MAJIS instrument team. Version 0.1 -- March 02, 2016 -- Jorge Diaz del Rio, ODC Space Preliminary version. Pending review by the MAJIS instrument and JUICE Science Operations Working Group team. Version 0.0 -- July 24, 2013 -- Marc Costa Sitja, ISDEFE/ESA Initial Release. References ------------------------------------------------------------------------------- 1. ``Kernel Pool Required Reading'' 2. ``C-kernel Required Reading'' 3. JUICE Frames Definition Kernel (FK), latest version. 4. ``JUICE - Jupiter Icy Moons Explorer. Exploring the emergence of habitable worlds around gas giants. Definition Study report,'' ESA/SRE(2014)1, September 2014 (JUICE Red book v1.0) 5. ``JUICE - JUpiter Icy Moons Explorer MAJIS - Moons And Jupiter Imaging Spectrometer Experiment Interface Document - Part B,'' JUI-IAS-MAJ-EID-001 Issue 1.2, 30 January 2014 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 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 [1] 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 ------------------------------------------------------------------------------- All names referencing values in this IK file start with the characters `INS' followed by the NAIF JUICE spacecraft ID number (-907) followed by a NAIF three digit ID code for one of the MAJIS ``sensors''. This is the full list of names and IDs for the MAJIS sensors described by this IK file: Name NAIF ID --------------------- --------- JUICE_MAJIS -907400 JUICE_MAJIS_VIRNIR -907410 JUICE_MAJIS_VIRNIR_B2 -907412 JUICE_MAJIS_VIRNIR_B4 -907414 JUICE_MAJIS_IR -907420 JUICE_MAJIS_IR_B2 -907422 JUICE_MAJIS_IR_B4 -907424 The remainder of the keyword name is an underscore character followed by the unique name of the data item. For example, the MAJIS Infrared sensor boresight direction in the JUICE_MAJIS_IR frame is specified by: INS-907420_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 and Overview ------------------------------------------------------------------------------- This section is extracted from the Experiment Interface Document - Part B (see [5]) Instrument Description: ----------------------- MAJIS instrument is composed by a compact double channel spectrometer sharing one single telescope. The telescope uses a three mirrors anastigmatic system design while the spectrometers adopt a double Czerny-Turner design. The two spectral channels cover the ranges between 0.4-1.9 microns (VIS-NIR channel) and 1.5-5.7 microns (IR channel). MAJIS concept design relies on a dual channel spectrometer architecture with a single slit sharing the same telescope equipped with a pointing/scanning mirror: a VIS-NIR channel, optimized to perform imaging spectroscopy in the 0.4-1.9 microns spectral range, and a IR channel operating simultaneously in the 1.5-5.7 microns. The spectral sampling of the VIS-NIR and IR channels is 2.3 nm/band and 6.6 nm/band, respectively. The minimum IFOV (by optical construction) is 125 micro-radians, which can be relaxed by operative modes through binning at any larger angle up to the FOV. The 3.4 degree FOV allows to cover a 30 km wide strip at 62.5 m/pixel resolution from a distance of 500 km. The bridging region of the two channels is set at 1.7 (+/-0.2) microns to guarantee an optimal overall SNR rather than a high spectral resolution in this range. Two 640x480 HgCdTe detectors are used as focal planes of the two channels. As typical for an imaging spectrometer, the instantaneous acquisition of the 2-D detectors consists of the slit image, 480 samples wide (spatial direction), diffracted by the grating across 640 bands (spectral direction). Repeating subsequent acquisitions, a hyperspectral data cube (or 3-D data set) is built, which associates a spectrum to each spatial pixel on ground. Since the two channels operate simultaneously, the instrument is able to collect an entire 0.4-5.7 microns spectrum for each pixel of the image, alternate designs of the focal plane are being considered retaining the same equivalent pixel pitch (30 microns).The instrument has the flexibility to operate both in pushbroom and in scanning modes, depending on the different phases of the mission. When the relative across-track MAJIS speed is too high or too low the instrument can operate by activating the scanning mode. In the first case the scanning mechanism will compensate the S/C motion compensation for high spatial observations at low distance from the target. This mode will be also used to acquire hyperspectral cubes and mosaics of Jupiter and Galilean satellites during transfer, elliptical or high altitude circular orbits. The data cube is then built by repeating consecutive acquisitions after having moved the scanning mirror by one IFOV step. Scan mirror unit ---------------- The scan mirror unit has a double functionality: a) it allows to build up a 2-D image with similar spatial resolution on both directions (along and across slit, the latter being the scan direction) when the relative speed of the target and MAJIS is too low (large slant distance); b) it allows to virtually increase the dwell time through a motion compensation mode when the relative speed is too high (short slant distance). For the mirror mechanism in motion compensation mode, the 200 km altitude orbit is most demanding (although not critical), because it requires an angular speed of 0.23 deg/s, and a spanning angle of +/- 4.03 deg to build a sequence of 250 lines. Binning ------- In order to maximize the scientific return of the instrument and to minimize the resource usage, several scientific operative modes are implemented. This approach guarantees flexibility of operation as well as full support to the science operations goals. The on board software for the two VIS-NIR and IR channels shall be capable of re-sampling the full frame instantaneous acquisition of 480 spatial x 640 spectral pixels in bins of variable size (x2, x4) in the spatial and spectral domain. In this way the spatial and spectral resolutions shall vary while maintaining the nominal 3.4 degree FOV, according to the modes described hereafter: Spatial Spectral Frame size Mode Binning iFOV(*) Binning nm/band(**) Samples Bands ---- ------- ------- ------- ----------- ------- ----- 1x1 1 125nrad 1 2.3/5.7 480 640 2x1 2 250nrad 1 2.3/5.7 240 640 4x1 4 500nrad 1 2.3/5.7 120 640 1x2 1 125nrad 2 4.6/11.4 480 320 2x2 2 250nrad 2 4.6/11.4 240 320 4x2 4 500nrad 2 4.6/11.4 120 320 1x4 1 125nrad 4 9.2/22.8 480 160 2x4 2 250nrad 4 9.2/22.8 240 160 4x4 4 500nrad 4 9.2/22.8 120 160 (*) Spatial resolution resulting from adding the iFoV the number of binned pixels. (**) Spectral resolution for the VIS-NIR/IR sensors. Mounting Alignment ------------------------------------------------------------------------------- Refer to the latest version of the JUICE Frames Definition Kernel (FK) [3] for the MAJIS reference frame definitions and mounting alignment information. MAJIS Apparent Field-of-View Layouts ------------------------------------------------------------------------------- This diagram illustrates the MAJIS VIS-NIR and IR apparent FOV layout for "zero" scan mirror position in the corresponding reference frame when operating in normal mode (no-binning). These FOVs are associated with detector instrument IDs (-907410 and -907420). ^ +Yvisnir (along track) | +Yir ^ direction | | | of | 125nrad | | flight | | v Pixel 1 | Pixel 480 --- +---------|---------+ | 1 line | o-------------> +Xvisnir (across track) --- +-------------------+ +Xir ^ 480 pixels/line | | 3.4 degrees | |<----------------->| | | Boresight (+Z axis) is out of the page This diagram illustrates the MAJIS VIS-NIR and IR apparent FOV layout for "zero" scan mirror position in the corresponding reference frame when operating in 2xN binning (2 pixels spatial binning mode). These FOVs are associated with detector instrument IDs (-907412 and -907422). ^ +Yvisnir_b2 (along track) | +Yir_b2 ^ direction | | | of | 250nrad | | flight | | v Pixel 1 | Pixel 240 --- +---------|---------+ | 1 line | o-------------> +Xvisnir_b2 (across track) --- +-------------------+ +Xir_b2 ^ 240 pixels/line | | 3.4 degrees | |<----------------->| | | Boresight (+Z axis) is out of the page This diagram illustrates the MAJIS VIS-NIR and IR apparent FOV layout for "zero" scan mirror position in the corresponding reference frame when operating in 4xN binning (4 pixels spatial binning mode). These FOVs are associated with detector instrument IDs (-907414 and -907424). ^ +Yvisnir_b4 (along track) | +Yir_b4 ^ direction | | | of | 500nrad | | flight | | v Pixel 1 | Pixel 120 --- +---------|---------+ | 1 line | o-------------> +Xvisnir_b4 (across track) --- +-------------------+ +Xir_b4 ^ 120 pixels/line | | 3.4 degrees | |<----------------->| | | Boresight (+Z axis) is out of the page This diagram illustrates the MAJIS VIR-NIR and IR apparent FOV layout resulting from a full, 480 step, +/- 1.7 degree scan mirror sweep about X axis. This FOV is associated with instrument ID -907400 and is useful only for rough coverage analysis as in reality the instrument does not always articulate the mirror over the whole possible range. ^ +Ymajis (along track) | | Pixel 1,1 | ^ direction --- *---------|---------+ | of ^ | | | | flight | ~3.4377 | | | | degrees | | | | | | | | 480 lines | o-------------> +Xmajis (across track) | (each for | | | a step in | | | scan seq.)| | V | | --- +-------------------+ | 480 pixels/line | 3.4 degrees | |<----------------->| | | Boresight (+Z axis) is out of the page Optical Parameters ------------------------------------------------------------------------------- TDB Detector Parameters ------------------------------------------------------------------------------- TBD MAJIS Field of View Definitions ------------------------------------------------------------------------------- The set of assignments in the data section below defines the MAJIS VIS-NIR and IR non-scanning FOVs with respect to the corresponding frames to be rectangles with the corners defined by the first and last pixels of the spatial, cross-track line and the boresight along the +Z axis. These FOV definitions use angular extent style specification with the cross and along track angular sizes taken from the ``Optics Parameters'' section above. Visible and Near-Infrared single line, no-binding FoV ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ \begindata INS-907410_FOV_FRAME = 'JUICE_MAJIS_VISNIR' INS-907410_FOV_SHAPE = 'RECTANGLE' INS-907410_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-907410_FOV_CLASS_SPEC = 'ANGLES' INS-907410_FOV_REF_VECTOR = ( 0.000000 1.000000 0.000000 ) INS-907410_FOV_REF_ANGLE = ( 0.00716197243913529 ) INS-907410_FOV_CROSS_ANGLE = ( 1.700 ) INS-907410_FOV_ANGLE_UNITS = 'DEGREES' \begintext Visible and Near-Infrared single line, 2-pixel spatial binding FoV ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ \begindata INS-907412_FOV_FRAME = 'JUICE_MAJIS_VISNIR' INS-907412_FOV_SHAPE = 'RECTANGLE' INS-907412_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-907412_FOV_CLASS_SPEC = 'ANGLES' INS-907412_FOV_REF_VECTOR = ( 0.000000 1.000000 0.000000 ) INS-907412_FOV_REF_ANGLE = ( 0.0143239448782706 ) INS-907412_FOV_CROSS_ANGLE = ( 1.700 ) INS-907412_FOV_ANGLE_UNITS = 'DEGREES' \begintext Visible and Near-Infrared single line, 4-pixel spatial binding FoV ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ \begindata INS-907414_FOV_FRAME = 'JUICE_MAJIS_VISNIR' INS-907414_FOV_SHAPE = 'RECTANGLE' INS-907414_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-907414_FOV_CLASS_SPEC = 'ANGLES' INS-907414_FOV_REF_VECTOR = ( 0.000000 1.000000 0.000000 ) INS-907414_FOV_REF_ANGLE = ( 0.0286478897565412 ) INS-907414_FOV_CROSS_ANGLE = ( 1.700 ) INS-907414_FOV_ANGLE_UNITS = 'DEGREES' \begintext Infrared single line, no-binding FoV ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ \begindata INS-907420_FOV_FRAME = 'JUICE_MAJIS_IR' INS-907420_FOV_SHAPE = 'RECTANGLE' INS-907420_BORESIGHT = ( 0.000000 0.000000 152.000000 ) INS-907420_FOV_CLASS_SPEC = 'ANGLES' INS-907420_FOV_REF_VECTOR = ( 0.000000 1.000000 0.000000 ) INS-907420_FOV_REF_ANGLE = ( 0.00716197243913529 ) INS-907420_FOV_CROSS_ANGLE = ( 1.700 ) INS-907420_FOV_ANGLE_UNITS = 'DEGREES' \begintext Infrared single line, 2-pixel spatial binding FoV ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ \begindata INS-907422_FOV_FRAME = 'JUICE_MAJIS_IR' INS-907422_FOV_SHAPE = 'RECTANGLE' INS-907422_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-907422_FOV_CLASS_SPEC = 'ANGLES' INS-907422_FOV_REF_VECTOR = ( 0.000000 1.000000 0.000000 ) INS-907422_FOV_REF_ANGLE = ( 0.0143239448782706 ) INS-907422_FOV_CROSS_ANGLE = ( 1.700 ) INS-907422_FOV_ANGLE_UNITS = 'DEGREES' \begintext Infrared single line, 4-pixel spatial binding FoV ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ \begindata INS-907424_FOV_FRAME = 'JUICE_MAJIS_VISNIR' INS-907424_FOV_SHAPE = 'RECTANGLE' INS-907424_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-907424_FOV_CLASS_SPEC = 'ANGLES' INS-907424_FOV_REF_VECTOR = ( 0.000000 1.000000 0.000000 ) INS-907424_FOV_REF_ANGLE = ( 0.0286478897565412 ) INS-907424_FOV_CROSS_ANGLE = ( 1.700 ) INS-907424_FOV_ANGLE_UNITS = 'DEGREES' \begintext MAJIS Full FoV ~~~~~~~~~~~~~~ The set of assignments in the data section below defines the MAJIS FOV resulting from a full, 480 step, +/- 1.7 degree scan mirror sweep about X axis with respect to MAJIS_BASE frame to be a rectangle with the corners defined by the first and last pixels of the spatial, along-track line in the first and last scan positions and the boresight along the +Z axis. \begindata INS-907400_FOV_FRAME = 'JUICE_MAJIS_BASE' INS-907400_FOV_SHAPE = 'RECTANGLE' INS-907400_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-907400_FOV_CLASS_SPEC = 'ANGLES' INS-907400_FOV_REF_VECTOR = ( 0.000000 1.000000 0.000000 ) INS-907400_FOV_REF_ANGLE = ( 1.7 ) INS-907400_FOV_CROSS_ANGLE = ( 1.7 ) INS-907400_FOV_ANGLE_UNITS = 'DEGREES' \begintext