KPL/IK ALICE Instrument kernel =========================================================================== This instrument kernel (I-kernel) contains Rosetta ALICE optics, detector, and field-of-view parameters. Version and Date --------------------------------------------------------------------------- Version 1.5 -- March 25, 2010 -- A. Steffl, SwRI Added coordinates of pixel centers. Version 1.4 -- January 26, 2010 -- J. Vazquez, ESAC/ESA / A. Steffl, SwRI Added boresight and instrument definitions for -X Wide Bottom and +X Wide Top, and the pinhole. Version 1.3 -- September 23, 2009 -- J. Vazquez, ESAC/ESA Removed non-printable characters from the kernel. Version 1.2 -- February 27, 2008 -- Andrew Steffl, SwRI Updated FOV corners to use values derived from in-flight observations Version 1.1 -- March 21, 2007 -- Andrew Steffl, SwRI Corrected erroneous instrument descriptions and changed slit shape to "POLYGON" to accurately reflect the shape of the Rosetta Alice entrance slit. Version 1.0 -- March 15, 2005 -- Boris Semenov, NAIF/JPL Version number change for the first official release. Version 0.2 -- March 15, 2005 -- Boris Semenov, NAIF/JPL Corrected FOV definition and relevant parameters and descriptions to ``line up'' the slit with +X axis of the ALICE frame. Version 0.1 -- September 2, 2004 -- Boris Semenov, NAIF/JPL Filled in instrument overview section (copied from [6]). Version 0.0 -- August 3, 2004 -- Boris Semenov, NAIF/JPL VERY PRELIMINARY VERSION. References --------------------------------------------------------------------------- 1. ``Kernel Pool Required Reading'' 2. ``C-kernel Required Reading'' 3. ``ALICE EID, Part B'', ROS-EST-RS-3005/EID B, 2001-02-15 4. Rosetta Frames Definition Kernel (FK), latest version. 5. ``ALICE: Experiment User Manual'', 8225-EUM-01, 2002-12-XX 6. ESA Science and Technology Web Server, Rosetta Instruments Area, http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=35061 7. ``Payload Boresight Alignment Details'', RO-EST-TN-3305, 2008/01/17 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 be used if the file contains instrument field-of-view (FOV) specification. See [1] 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 [1]. All keywords referencing values in this I-kernel start with the characters `INS' followed by the NAIF Rosetta instrument ID code, constructed using the spacecraft ID number (-226) followed by the NAIF three digit ID number for ALICE (120). ALICE ID(s) is defined in [4]. The remainder of the keyword is an underscore character followed by the unique name of the data item. For example, the focal length of the ALICE optics is specified by INS-226120_FOCAL_LENGTH The upper bound on the length of all keywords is 32 characters. If a keyword is included in more than one file, or if the same keyword appears more than once within a single file, the last assignment supersedes any earlier assignments. Overview -------------------------------------------------------- From [6]: ALICE, an Ultraviolet Imaging Spectrometer, will characterize the composition of the nucleus and coma, and the nucleus/coma coupling of comet 67 P/Churyumov-Gerasimenko. This will be accomplished through the observation of spectral features in the extreme and far ultraviolet (EUV/FUV) spectral regions from 70 to 205 nm. ALICE will make measurements of noble gas abundances in the coma, the atomic budget in the coma, and major ion abundances in the tail and in the region where solar wind particles interact with the ionosphere of the comet. ALICE will determine the production rates, variability, and structure of H2O and CO, and CO2 gas surrounding the nucleus and the far-UV properties of solid grains in the coma. ALICE will also map the cometary nucleus in the FUV, and study Mars and the Rosetta asteroid flyby targets while en route to Churyumov-Gerasimenko. Summary of ALICE Characteristics Wavelength range (nm): 70-205 Spectral resolution, (extended source, FWHM) (nm): 1.0 (at 70 nm), 1.3 (at 205 nm) Spectral resolution, (point source, FWHM) (nm): 0.3-0.5 Spatial resolution (degrees): 0.1 x 0.5 Nominal sensitivity (counts s-1 R-1): 0.5 (at 190 nm); 7.8 (at 115 nm) Field of view (degrees): 0.1 x 6.0 Pointing: Boresight approximately co-aligned with OSIRIS, VIRTIS Observation types: Nucleus imaging and spectroscopy; Coma spectroscopy; Jet and grain spectrophotometry; Stellar occultations (secondary observations) Telescope: 40 x 40 mm entrance pupil; 41 x 65 mm, f3, off-axis paraboloid primary mirror; 120 mm focal length Spectrograph: Rowland Circle style imaging spectrograph; 0.1 (0.05 in center) x 6 deg entrance slit; 50 x 50 mm toroidal holographic diffraction grating Detector: 2-D (1024 x 32 pixels) microchannel plate using a double delay line (DDL) readout Mass (kg): 2.7 Dimensions (l x w x h, mm): 204 x 413 x 140 Power consumption (average, W): 4.0 Mounting Alignment -------------------------------------------------------- Refer to the latest version of the Rosetta Frames Definition Kernel (FK) [4] for the ALICE reference frame definitions and mounting alignment information. Apparent FOV Layout -------------------------------------------------------- This section provides a diagram illustrating the ALICE apparent detector layout in the corresponding reference frame. ^ +X_alice (along slit) | | o Pinhole (Approximately Row 25)--- ^ | ^ | +---|---+ Row 23 | | | | | | | ----> | | |<---- 0.1 degrees | | | | | | | | | | | | | o | +X_WIDE_TOP | | | | | | 2 deg. | | | | | | | | | | | | | | | | | | | | | |_ | _| ___ _v_ | | | | ^ | ---->| | |<---- 0.05 degrees | | | | | | | | | | | | | | | | | +Y_alice (cross slit) | | | ROS_ALICE_CENTER | | <----------------------|-o-|---- | 2 deg. | 6 deg. | | | | | | | | | | | | | | | | | | | | | | | | | _| | |_ _v_ ___ | | | | ^ | | | | | | | | | | | | | | | | | | | | | | | | | | | o | -X_WIDE_BOTTOM | | | | | | 2 deg. | | | | | | | | | | | | | | | | | | | | | | | | | | | | | v v +---|---+ Row 5 --- --- | Alice instrument boresight (+Z_alice) out of the page There are 32 pixels in the along-slit, spatial direction. However, only rows 5-23 (inclusive) are illuminated by the entrance slit. In addition to the main slit, there is a 1-milliradian diameter pinhole that illuminates row 25. There is effectively no spatial resolution in the cross-slit (spectral) direction. Thus, the 1024 pixels in this direction are used to achieve the desired spectral resolution. Optical Distortion -------------------------------------------------------- The Alice primary mirror introduces some optical distortion (primarily coma). Thus, the projection of the Alice entrance slit onto the sky is not rectilinear. Optical Parameters -------------------------------------------------------- The following ALICE nominal first order optical parameters are included in the data section below, from [3]: ----------------------------------------------------------------- parameter value note ----------------------------------------------------------------- Focal Length, mm 120.0 f/ratio f/3 IFOV, rad/pixel Cross-track 0.001745 Along-track 0.005376 Field of view (deg) Cross-track 0.1 value is 0.05 in center Along-track 6.0 ----------------------------------------------------------------- FOV and IFOV parameters above are for the spatial direction. 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-226120_FOCAL_LENGTH = ( 120.0 ) INS-226120_F/RATIO = ( 3.0 ) INS-226120_FOV_ANGULAR_SIZE = ( 0.001745, 0.104720 ) INS-226120_IFOV = ( 0.001745, 0.005376 ) \begintext Detector Parameters -------------------------------------------------------- The nominal ALICE detector parameters from [6] are: ----------------------------------------------------------------- parameter value note ----------------------------------------------------------------- Detector Array Size ---- Physical Cross-slit 1024 spectral dimension Along-slit 32 spatial dimension Detector Array Size ---- Spatial Cross-slit 1 Effectively, there is no spatial resolution in the cross-slit direction Along-slit 32 only rows 5-23 illuminated Detector Array Center -- Spatial Cross-slit 0.5 Along-slit 15.5 ----------------------------------------------------------------- The values are given in counts for PIXEL_SAMPLES, PIXEL_LINES, and CENTER keywords. \begindata INS-226120_PIXEL_SAMPLES = ( 1 ) INS-226120_PIXEL_LINES = ( 32 ) INS-226120_CCD_CENTER = ( 0.5, 15.5 ) \begintext FOV Definitions --------------------------------------------------------------------------- This section contains definitions for the ALICE FOV. This definition is provided in the format required by the SPICE (CSPICE) function GETFOV (getfov_c). \begindata INS-226120_FOV_FRAME = 'ROS_ALICE' INS-226120_FOV_SHAPE = 'POLYGON' INS-226120_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-226120_FOV_CLASS_SPEC = 'CORNERS' INS-226120_FOV_BOUNDARY_CORNERS = ( 0.044721062315 -0.000704526509 1.000000000000 0.044348043165 -0.001132901540 1.000000000000 0.018202454381 -0.000896519481 1.000000000000 0.017692696428 -0.000685847442 1.000000000000 0.011949833432 -0.000378340802 1.000000000000 -0.011928236903 -0.000541432536 1.000000000000 -0.016703724088 -0.000880602400 1.000000000000 -0.017101663044 -0.001134745209 1.000000000000 -0.051532633282 -0.001829753266 1.000000000000 -0.051532791827 -0.000220135885 1.000000000000 -0.049830936432 0.000160445314 1.000000000000 -0.017667203258 0.000732004676 1.000000000000 -0.016687860334 0.000348078680 1.000000000000 0.017830104779 0.000595950114 1.000000000000 0.018582049915 0.001049392745 1.000000000000 0.041940365358 0.000891496662 1.000000000000 0.044568913704 0.000364935529 1.000000000000 ) INS-226120_PIXEL_CENTERS = ( -0.083912644543 -0.002114578970 1.000000000000 -0.078559414280 -0.001868062959 1.000000000000 -0.073177584329 -0.001636534053 1.000000000000 -0.067766922094 -0.001419991951 1.000000000000 -0.062327184828 -0.001218436357 1.000000000000 -0.056858119441 -0.001031866986 1.000000000000 -0.051359462297 -0.000860283556 1.000000000000 -0.045830939007 -0.000703685791 1.000000000000 -0.040272264216 -0.000562073417 1.000000000000 -0.034683141378 -0.000435446164 1.000000000000 -0.029063262536 -0.000323803762 1.000000000000 -0.023412308078 -0.000227145941 1.000000000000 -0.017729946501 -0.000145472432 1.000000000000 -0.012015834153 -0.000078782962 1.000000000000 -0.006269614979 -0.000027077259 1.000000000000 -0.000490920251 0.000009644952 1.000000000000 0.005320631712 0.000031383949 1.000000000000 0.011165435830 0.000038140014 1.000000000000 0.017043900556 0.000029913431 1.000000000000 0.022956448190 0.000006704487 1.000000000000 0.028903515188 -0.000031486526 1.000000000000 0.034885552504 -0.000084659315 1.000000000000 0.040903025918 -0.000152813581 1.000000000000 0.046956416399 -0.000235949026 1.000000000000 0.053046220470 -0.000334065346 1.000000000000 0.059172950582 -0.000447162237 1.000000000000 0.065337135514 -0.000575239393 1.000000000000 0.071539320780 -0.000718296507 1.000000000000 0.077780069048 -0.000876333272 1.000000000000 0.084059960584 -0.001049349384 1.000000000000 0.090379593705 -0.001237344537 1.000000000000 0.096739585251 -0.001440318432 1.000000000000 ) \begintext Alice has two extra boresights, situated approximately at the center of the top and bottom wide parts of the slit. The offset of these two vectors and the boresight from the Z axis of the spacecraft are given in [7]: Offset from Zs/c Offset from Zs/c along Xs/c (deg) along Ys/c (deg) (alpha) (betha) ------------------------------------------------------------------- Alice Narrow center 0.062 -0.098 Alice -X Wide Bottom -1.95 -0.129 Alice +X Wide Top 2.05 -0.101 In order to compute the two extra boresights in the ROS_ALICE frame, the following steps were taken: 1) Compute the vectors in the ROS_SPACECRAFT frame. The vectors are in the form [ x, y, 1 ], where x and y are computed as: x = tan( alpha ) y = tan( betha ) 2) Compute the coordinates of the vectors in the ROS_ALICE frame. For example, using IDL, for Alice -X Wide Bottom: cspice_pxform, 'ros_spacecraft', 'ros_alice', 0, tx x = tan( -1.95 * cspice_rpd() ) y = tan( -0.098 * cspice_rpd() ) cspice_mxv, tx, [ x, y, 1 ], v For each of the extra boresights, a complete instrument with its boresight and field of view is defined. The field of view is the same as the one for the main instrument (ROS_ALICE_CENTER). This way, users can fetch the boresight and field for the three different instruments in the same way, using, for instance, the GETFOV routine. -X_WIDE_BOTTOM: ------------- \begindata INS-226122_FOV_FRAME = 'ROS_ALICE' INS-226122_FOV_SHAPE = 'POLYGON' INS-226122_BORESIGHT = ( -0.035129152 -0.00054111906 0.99996496 ) INS-226122_FOV_CLASS_SPEC = 'CORNERS' INS-226122_FOV_BOUNDARY_CORNERS = ( 0.044721062315 -0.000704526509 1.000000000000 0.044348043165 -0.001132901540 1.000000000000 0.018202454381 -0.000896519481 1.000000000000 0.017692696428 -0.000685847442 1.000000000000 0.011949833432 -0.000378340802 1.000000000000 -0.011928236903 -0.000541432536 1.000000000000 -0.016703724088 -0.000880602400 1.000000000000 -0.017101663044 -0.001134745209 1.000000000000 -0.051532633282 -0.001829753266 1.000000000000 -0.051532791827 -0.000220135885 1.000000000000 -0.049830936432 0.000160445314 1.000000000000 -0.017667203258 0.000732004676 1.000000000000 -0.016687860334 0.000348078680 1.000000000000 0.017830104779 0.000595950114 1.000000000000 0.018582049915 0.001049392745 1.000000000000 0.041940365358 0.000891496662 1.000000000000 0.044568913704 0.000364935529 1.000000000000 ) INS-226122_PIXEL_CENTERS = ( -0.083912644543 -0.002114578970 1.000000000000 -0.078559414280 -0.001868062959 1.000000000000 -0.073177584329 -0.001636534053 1.000000000000 -0.067766922094 -0.001419991951 1.000000000000 -0.062327184828 -0.001218436357 1.000000000000 -0.056858119441 -0.001031866986 1.000000000000 -0.051359462297 -0.000860283556 1.000000000000 -0.045830939007 -0.000703685791 1.000000000000 -0.040272264216 -0.000562073417 1.000000000000 -0.034683141378 -0.000435446164 1.000000000000 -0.029063262536 -0.000323803762 1.000000000000 -0.023412308078 -0.000227145941 1.000000000000 -0.017729946501 -0.000145472432 1.000000000000 -0.012015834153 -0.000078782962 1.000000000000 -0.006269614979 -0.000027077259 1.000000000000 -0.000490920251 0.000009644952 1.000000000000 0.005320631712 0.000031383949 1.000000000000 0.011165435830 0.000038140014 1.000000000000 0.017043900556 0.000029913431 1.000000000000 0.022956448190 0.000006704487 1.000000000000 0.028903515188 -0.000031486526 1.000000000000 0.034885552504 -0.000084659315 1.000000000000 0.040903025918 -0.000152813581 1.000000000000 0.046956416399 -0.000235949026 1.000000000000 0.053046220470 -0.000334065346 1.000000000000 0.059172950582 -0.000447162237 1.000000000000 0.065337135514 -0.000575239393 1.000000000000 0.071539320780 -0.000718296507 1.000000000000 0.077780069048 -0.000876333272 1.000000000000 0.084059960584 -0.001049349384 1.000000000000 0.090379593705 -0.001237344537 1.000000000000 0.096739585251 -0.001440318432 1.000000000000 ) \begintext +X_WIDE_TOP: ----------- \begindata INS-226123_FOV_FRAME = 'ROS_ALICE' INS-226123_FOV_SHAPE = 'POLYGON' INS-226123_BORESIGHT = ( 0.034712399 -5.2296517e-05 1.0000397 ) INS-226123_FOV_CLASS_SPEC = 'CORNERS' INS-226123_FOV_BOUNDARY_CORNERS = ( 0.044721062315 -0.000704526509 1.000000000000 0.044348043165 -0.001132901540 1.000000000000 0.018202454381 -0.000896519481 1.000000000000 0.017692696428 -0.000685847442 1.000000000000 0.011949833432 -0.000378340802 1.000000000000 -0.011928236903 -0.000541432536 1.000000000000 -0.016703724088 -0.000880602400 1.000000000000 -0.017101663044 -0.001134745209 1.000000000000 -0.051532633282 -0.001829753266 1.000000000000 -0.051532791827 -0.000220135885 1.000000000000 -0.049830936432 0.000160445314 1.000000000000 -0.017667203258 0.000732004676 1.000000000000 -0.016687860334 0.000348078680 1.000000000000 0.017830104779 0.000595950114 1.000000000000 0.018582049915 0.001049392745 1.000000000000 0.041940365358 0.000891496662 1.000000000000 0.044568913704 0.000364935529 1.000000000000 ) INS-226123_PIXEL_CENTERS = ( -0.083912644543 -0.002114578970 1.000000000000 -0.078559414280 -0.001868062959 1.000000000000 -0.073177584329 -0.001636534053 1.000000000000 -0.067766922094 -0.001419991951 1.000000000000 -0.062327184828 -0.001218436357 1.000000000000 -0.056858119441 -0.001031866986 1.000000000000 -0.051359462297 -0.000860283556 1.000000000000 -0.045830939007 -0.000703685791 1.000000000000 -0.040272264216 -0.000562073417 1.000000000000 -0.034683141378 -0.000435446164 1.000000000000 -0.029063262536 -0.000323803762 1.000000000000 -0.023412308078 -0.000227145941 1.000000000000 -0.017729946501 -0.000145472432 1.000000000000 -0.012015834153 -0.000078782962 1.000000000000 -0.006269614979 -0.000027077259 1.000000000000 -0.000490920251 0.000009644952 1.000000000000 0.005320631712 0.000031383949 1.000000000000 0.011165435830 0.000038140014 1.000000000000 0.017043900556 0.000029913431 1.000000000000 0.022956448190 0.000006704487 1.000000000000 0.028903515188 -0.000031486526 1.000000000000 0.034885552504 -0.000084659315 1.000000000000 0.040903025918 -0.000152813581 1.000000000000 0.046956416399 -0.000235949026 1.000000000000 0.053046220470 -0.000334065346 1.000000000000 0.059172950582 -0.000447162237 1.000000000000 0.065337135514 -0.000575239393 1.000000000000 0.071539320780 -0.000718296507 1.000000000000 0.077780069048 -0.000876333272 1.000000000000 0.084059960584 -0.001049349384 1.000000000000 0.090379593705 -0.001237344537 1.000000000000 0.096739585251 -0.001440318432 1.000000000000 ) \begintext PINHOLE: ----------- \begindata INS-226124_FOV_FRAME = 'ROS_ALICE' INS-226124_FOV_SHAPE = 'CIRCLE' INS-226124_BORESIGHT = ( 0.052407779 -0.00022084111 1.00000000 ) INS-226124_FOV_CLASS_SPEC = 'ANGLES' INS-226124_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-226124_FOV_REF_ANGLE = ( 0.02 ) INS-226124_FOV_ANGLE_UNITS = 'DEGREES' \begintext Platform ID --------------------------------------------------------------------------- This number is the NAIF instrument ID of the platform on which the instrument mounted. For Alice, it is the spacecraft. \begindata INS-226120_PLATFORM_ID = ( -226000 ) INS-226122_PLATFORM_ID = ( -226000 ) INS-226123_PLATFORM_ID = ( -226000 ) INS-226124_PLATFORM_ID = ( -226000 ) \begintext