KPL/IK SIR-2 Instrument kernel =========================================================================== This instrument kernel (I-kernel) contains CHANDRAYAAN-1 Near Infrared Spectrometer (SIR-2) optics, detector, and FOV parameters. Version and Date --------------------------------------------------------------------------- Version 0.1 -- 2008 November 18 -- Bjoern Grieger, ESA/SRE-OS Changed the instrument ID from 200 to 700, as defined in the preliminary frames kernel ch1_sample.tf from 2008-Nov-12. Confirmed that the fiber shape is circle. Changed the fiber size from 0.200 mm to 0.400 mm. Confirmation of spectral range and approval by team is still pending. Version 0.0 -- 2008 October 13 -- Bjoern Grieger, ESA/SRE-OS Preliminary Version. Copied from the SMART-1 SIR kernel (created by Jorge Diaz del Rio) and updated spacecraft name and ID, instrument name, and the IFOV. Copied the instrument overview from the SIR-2 ICD. The instrument ID is still set to the SMART-1 value (200); this has certainly to be updated when the FK is available. Pending review and approval by SIR-2 instrument team. References --------------------------------------------------------------------------- 1. ``Kernel Pool Required Reading'' 2. ``C-kernel Required Reading'' 3. ``SIR-2 ICD'', C1-SIR-ICD-3001, V2.3, 2007-Sep-26 4. CH1 Frames Definition Kernel (FK), (not yet available). Contact Information ------------------------------------------------------------------------ Bjoern Grieger, ESA/SRE-OS, +34 91 81 31 107, bgrieger@sciops.esa.int 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 also be used if the file contains instrument field-of-view (FOV) specifications. See [1] for details. This file was created and can be updated with a text editor or word processor. Conventions for Specifying Data ------------------------------------------------------------------------ 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 CHANDRAYAAN-1 instrument ID code, constructed using the spacecraft ID number, -86, followed by the NAIF three digit ID number for SIR-2 (700). This ID is defined in [4] as follows: Instrument name ID -------------------- ------- CH1_SIR2 -86700 The remainder of the keyword is an underscore character followed by the unique name of the data item. For example, the number of pixels of the SIR-2 is specified by INS-86700_NUMBER_OF_PIXELS The upper bound on the length of all keywords is 32 characters. If a keyword is included in more then one file, or if the same keyword appears more than once within a single file, the last assignment supersedes any earlier assignments. Instrument Overview ------------------------------------------------------------------------ From [3]: SIR-2 is a highly compact, grating, near-infrared point spectrometer, covering the wavelength range between 0.9 and 2.4 microns, with a spectral resolution of 6 nm. The near-infrared spectrometer SIR-2 consists of three individual units: - O-Box (front-end optics), located on an extension of the Anti-SS panel - Sensor-Head/Radiator Unit (spectrometer), located on the Anti-SS panel - E-Box (digital electronics and power converter), located inside the S/C cube on the Anti-SS panel These units are linked by: - An optical fiber connecting O-Box and Sensor-Head/Radiator Unit - An electrical harness (ILH) connecting Sensor-Head/Radiator Unit and E-Box SIR-2 collects the Sun's light reflected by the Moon with the help of the optical box (O-Box) which houses a main and secondary mirror. This light then enters an optical fiber, which transmits the light to the Sensor-Head/Radiator Unit. Inside the Sensor-Head the light passes filter, slit and the quartz body and reaches the dispersing grating. The dispersed light then passes the quartz body again to reach a second order filter, which is glued onto the detector window. After passing this window the light is detected by the photosensitive pixels. The electrons released by the individual pixels are collected and a sequential read out is performed after the integration time has ended. The adjacent voltage will be measured for each pixel and the obtained values are converted to digits. The obtained values (counts) are finally embedded in the TM packages in order to send them to the spacecraft's mass memory. Mounting Alignment ------------------------------------------------------------------------ Refer to the latest version of the CHANDRAYAAN-1 Frames Definition Kernel (FK) [4] for the SIR-2 reference frame definitions and mounting alignment information. Optics and Detector Parameters ------------------------------------------------------------------------ This section contains assignments specifying the SIR-2 optics and detector parameters. The following SIR-2 optical and fiber shape/size parameters are included in the data section below, taken from [3]: ----------------------------------------------------------------- parameter SIR-2 ----------------------------------------------------------------- Focal Length, mm 180 f/ratio 2.5 Fiber shape circle Fiber size, mm 0.400 Number of pixels 1 IFOV, rad/pixel nominal 0.0022 ----------------------------------------------------------------- These values are provided in the assignments below, with the same units as in the table. \begindata INS-86700_FOCAL_LENGTH = ( 180 ) INS-86700_F/RATIO = ( 2.5 ) INS-86700_FIBER_SIZE = ( 0.200 ) INS-86700_NUMBER_OF_PIXELS = ( 1 ) INS-86700_IFOV = ( 0.0022 ) \begintext FOV Definitions ------------------------------------------------------------------------ This section contains assignments defining the SIR-2 FOV. These definitions are based on the SIR-2 detector and optics parameters provided in the previous section and are provided in a format consistent with/required by the SPICE (CSPICE) function GETFOV (getfov_c). The SIR-2 FOV is defined as a cone with a half angle of 0.0011 radians. It is defined with respect to the CH1_SIR2 frame. The boresight vector, along the +Z axis of the frame, was scaled to be equal to the focal length. The cross-reference vector is a unit vector along the +X axis of the frame. \begindata INS-86700_FOV_FRAME = 'CH1_SIR2' INS-86700_FOV_SHAPE = 'CIRCLE' INS-86700_BORESIGHT = ( 0.0 0.0 180.0 ) INS-86700_FOV_CLASS_SPEC = 'ANGLES' INS-86700_FOV_REF_VECTOR = ( 1.0 0.0 0.0 ) INS-86700_FOV_REF_ANGLE = ( 0.0011 ) INS-86700_FOV_CROSS_ANGLE = ( 0.0011 ) INS-86700_FOV_ANGLE_UNITS = 'RADIANS' \begintext Spectral Parameters ------------------------------------------------------------------------ This section contains assignments specifying SIR-2 spectral resolution parameters. The SIR-2 spectral resolution parameters, included in the data section below, are taken from [3]. ----------------------------------------------------------------- parameter SIR-2 ----------------------------------------------------------------- Spectral range, microns nominal 0.9 - 2.40 (S1-SIR was 0.94 ???) Number of spectral bins 256 ----------------------------------------------------------------- These values are provided in the assignments below, with the same units as in the table. \begindata INS-86700_SPECTRAL_RANGE = ( 0.9, 2.40 ) INS-86700_NUMBER_OF_BINS = ( 256 ) \begintext Platform ID ------------------------------------------------------------------------ This number is the NAIF instrument ID of the platform on which the instrument is mounted. SIR-2 is mounted directly on the spacecraft. \begindata INS-86700_PLATFORM_ID = ( -86000 ) \begintext