KPL/IK UVS Instrument Kernel =============================================================================== This instrument kernel (I-kernel) contains the JUICE Ultraviolet Spectrograph (UVS) instrument optics, detector and field-of-view (FOV) paramters. Version and Date ------------------------------------------------------------------------------- Version 0.2 -- May 11, 2016 -- Jorge Diaz del Rio, ODC Space Added instrument description section. Corrected typos in text. Modified INS-907851_FOV_FRAME keyword value (to JUICE_UVS) Version 0.1 -- February 24, 2016 -- Jorge Diaz del Rio, ODC Space Preliminary version. Pending review by the UVS 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) 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 UVS sensors. This is the full list of names and IDs for the UVS sensors described by this IK file: Name NAIF ID --------------------- --------- JUICE_UVS_AP -907851 JUICE_UVS_AP_NARROW -907852 JUICE_UVS_AP_WIDE -907853 JUICE_UVS_HP -907860 JUICE_UVS_SP -907870 The remainder of the keyword name is an underscore character followed by the unique name of the data item. For example, the UVS Airglow Aperture boresight direction in the JUICE_UVS frame is specified by: INS-907851_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 ------------------------------------------------------------------------------- UVS is a long-slit ultraviolet imaging spectrograph, with a spectral bandpass including extreme and far-ultraviolet wavelengths in the 55-210 nm range, which will be used to (see [4]): 1) Explore the atmospheres, plasma interactions, and surfaces of the Galilean satellites; 2) Determine the dynamics, chemistry, and vertical structure of Jupiter's upper atmosphere, from equator to pole; and 3) Investigate the Jupiter-Io connection by quantifying energy and mass flow in the Io atmosphere, neutral clouds, and torus. UVS will obtain airglow and auroral observations, stellar and solar occultations, Jupiter transit, mutual event and surface albedo maps to address JUICE science goals even in the worst-case radiation environment near Europa. The main characteristics of UVS are provided in the following table: ----------------------------------------------------------------------- PARAMETER VALUE --------------------------- ----------------------------------------- Wavelength Bandpass 55-210 nm Effective Area 0.6 cm2 at 125 nm for AP Slit FOV 0.1x7.3 degrees (AP) + 0.2 degrees (SP) Spectral Resolution (PSF) <0.6 nm FWHM, bandpass average Spectral Resolution 1.2 nm FWHM, bandpass average (filled slit) Spatial Resolution (PSF) Nyquist sampled: 0.16 degrees for AP/SP; 0.04 degrees for HP Pixel Resolution 0.02 degrees Stray Light Rejection <10-6 at 7 degreess off-boresight Detector Deadtime TD ~ 1.2 microseconds; ~ 30% loss at 360 kHz Detector Global Background Total array: less than 20 counts/s during Rate cruise; 2.5 counts/s on ground; typically 1-100 kHz Detector Output Continuous, time-tagged pixel list or programmable histogram mode with "ping-pong" memory fill. ------------------------------------------------------------------------ The telescope feeds a 15-cm Rowland circle spectrograph with a spectral bandpass of 55-210 nm. The telescope has an input aperture 4x4 cm2 and uses an off-axis parabolic (OAP) primary mirror. Light from the OAP is focused onto the spectrograph entrance slit, which has two contiguous segments with fields-of-view (FOV) of 0.1x7.3 degrees and 0.2x0.2 degrees projected onto the sky (the 0.2x0.2 degrees box is used to accommodate the 0.11 degrees diameter Sun during solar occultations). Light entering the slit is dispersed by a toroidal diffraction grating that focuses the UV bandpass onto a curved microchannel plate (MCP) cross delay line (XDL) detector with a solar blind, UV-sensitive CsI photocathode. Tantalum/Tungsten (TaW) plates contiguously surround the detector and electronics assemblies, shielding the detector and sensitive parts from general particle radiation and high-energy electrons in particular. The detector electronics are located behind the detector. In a chamber beside the spectrograph are located the high-voltage power supply (HVPS), low-voltage power supply (LVPS), command and data handling (C&DH) electronics, heater/actuator activation electronics, and event processing electronics. The detector electronics receive event pulses from the detector and provide a digital indication of the spatial and spectral location of each event to the C&DH. Event processing electronics receive valid individual events and process them into: 1) pixel list (a time ordered record of detected events) or 2) programmable histogram. A main entrance "airglow port" (AP) is used for most observations (e.g., airglow, aurora, surface mapping, and stellar occultations), while a separate "solar port" (SP), at an angle of 60 degrees to the AP, allows for solar occultations. Another aperture door, with a small hole through the centre, is used as a "high-spatial-resolution port" (HP) for detailed observations of bright targets. Time-tagging (pixel-list mode) and programmable spectral imaging (histogram mode) allow for observational flexibility and optimal data management. Mounting Alignment ------------------------------------------------------------------------------- Refer to the latest version of the JUICE Frames Definition Kernel (FK) [3] for the UVS reference frame definitions and mounting alignment information. UVS Slit Layout ------------------------------------------------------------------------------- This section provides a diagram illustrating the UVS apparent slit layout in the JUICE_UVS reference frame. ^ +Xuvs (along slit) | | | | v .--|--. ---------------------- ----> | _._ | <---- 0.2 degrees ^ | ' | JUICE_UVS_AP_WIDE | '-.|.-' --------- | ||| ^ ^ | ||| | | | ||| 0.2 deg. | | | ||| | | ||| | | ||| | | ||| | | ||| | | ---->|||<---- 0.1 degrees | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| | | +Yuvs (cross slit) ||| | | <-----------------------|o| JUICE_UVS_AP | 7.5deg. | ||| | | ||| | | |o| JUICE_UVS_AP_NARROW | | ||| | | ||| 7.3 deg. | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| | | ||| v v '-' ---------------------- UVS +Z axis (instrument main boresight) out of the page Optical Distortion ------------------------------------------------------------------------------- TBD; need consultation with UVS instrument team Optical Parameters ------------------------------------------------------------------------------- TBD; need consultation with UVS instrument team Detector Parameters -------------------------------------------------------- TBD; need consultation with UVS instrument team UVS Airglow Port Field of View Definition ------------------------------------------------------------------------------- The UVS Airglow Port field of view is defined based on the shape of the spectrograph entrance slit, which has two contiguous segments with fields of view of 0.1x7.3 degrees and 0.2x0.2 degrees (see [4], p.54). \begindata INS-907851_FOV_FRAME = 'JUICE_UVS' INS-907851_FOV_SHAPE = 'POLYGON' INS-907851_BORESIGHT = ( 0.000, 0.000, 1.000 ) INS-907851_FOV_CLASS_SPEC = 'CORNERS' INS-907851_FOV_BOUNDARY_CORNERS = ( -0.0654031044274081 0.0008708943631663 0.997858544821993 -0.0654031044274081 -0.0008708943631663 0.997858544821993 0.0619195296276383 -0.0008708943631663 0.998080764965291 0.0619194588007405 -0.0017453257076200 0.998079623306677 0.0654030296158094 -0.0017453257076200 0.997857403417567 0.0654030296158094 0.0017453257076200 0.997857403417567 0.0619194588007405 0.0017453257076200 0.998079623306677 0.0619195296276383 0.0008708943631663 0.998080764965291 ) \begintext UVS has two extra boresights, situated approximately at the center of the wide and narrow parts of the slit. The offset of these two vectors and the boresight from the UVS Z axis are: Offset from Zuvs Offset from Zuvs along Xuvs (deg) along Yuvs (deg) (alpha) (betha) ------------------------------------------------------------------- UVS AP Narrow center -0.100 0.000 UVS AP Wide center +3.850 0.000 In order to compute the two extra boresights in the JUICE_UVS frame, the following steps were taken: 1) Compute the vectors in the JUICE_UVS frame. The vectors are in the form [ x, y, 1 ], where x and y are computed as: x = tan( alpha ) y = tan( betha ) 2) Normalize the resulting vector For each of the extra boresights, a complete instrument with its boresight and field of view is defined. The 'combined' field of view is the same as the one for the Airglow Port sensor (JUICE_UVS_AP). This way, users can fetch the boresight and field for the three different instruments in the same way. UVS Airglow Port Narrow FoV: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ \begindata INS-907852_FOV_FRAME = 'JUICE_UVS' INS-907852_FOV_SHAPE = 'RECTANGLE' INS-907852_BORESIGHT = ( -0.00174532836589831 0.00000000 0.999998476913288 ) INS-907852_FOV_CLASS_SPEC = 'ANGLES' INS-907852_FOV_REF_VECTOR = ( 0.000000 1.000000 0.000000 ) INS-907852_FOV_REF_ANGLE = ( 0.05 ) INS-907852_FOV_CROSS_ANGLE = ( 3.65 ) INS-907852_FOV_ANGLE_UNITS = 'DEGREES' \begintext UVS Airglow Port Wide FoV: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ \begindata INS-907853_FOV_FRAME = 'JUICE_UVS' INS-907853_FOV_SHAPE = 'RECTANGLE' INS-907853_BORESIGHT = ( 0.0636614381316129 0.000000 0.997971553349531 ) INS-907853_FOV_CLASS_SPEC = 'ANGLES' INS-907853_FOV_REF_VECTOR = ( 0.000000 1.000000 0.000000 ) INS-907853_FOV_REF_ANGLE = ( 0.1 ) INS-907853_FOV_CROSS_ANGLE = ( 0.1 ) INS-907853_FOV_ANGLE_UNITS = 'DEGREES' \begintext UVS High-spatial-resolution (HS) Field of View Definition ------------------------------------------------------------------------------- The UVS High-spatial-resolution (HS) field of view is defined based on a small hole of 5mm in the centre of the Airglow Port Aperture Door. This hole, along with the main slit, corresponds to a field of view of 0.1 degrees in the UVS +Y direction and 0.9375 degrees (TBC) in the UVS +X direction. The value 0.9375 is obtained assuming that 40mm aperture along the +X UVS axis corresponds to 7.5 degrees, and that the 5mm hole is located at the same distance from the focal point as the 40mm aperture. THIS ASPECT NEEDS TO BE CONFIRMED BY THE UVS INSTRUMENT TEAM. \begindata INS-907860_FOV_FRAME = 'JUICE_UVS' INS-907860_FOV_SHAPE = 'RECTANGLE' INS-907860_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-907860_FOV_CLASS_SPEC = 'ANGLES' INS-907860_FOV_REF_VECTOR = ( 0.000000 1.000000 0.000000 ) INS-907860_FOV_REF_ANGLE = ( 0.05 ) INS-907860_FOV_CROSS_ANGLE = ( 0.46875 ) INS-907860_FOV_ANGLE_UNITS = 'DEGREES' \begintext UVS Sun Port Field of View Definition ------------------------------------------------------------------------------- The UVS Sun Port field of view is defined based on the shape of the spectrograph entrance slit wide part, which has square field of view of 0.2x0.2 degrees (see [4], p.53). \begindata INS-907870_FOV_FRAME = 'JUICE_UVS_SP' INS-907870_FOV_SHAPE = 'RECTANGLE' INS-907870_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-907870_FOV_CLASS_SPEC = 'ANGLES' INS-907870_FOV_REF_VECTOR = ( 0.000000 1.000000 0.000000 ) INS-907870_FOV_REF_ANGLE = ( 0.1 ) INS-907870_FOV_CROSS_ANGLE = ( 0.1 ) INS-907870_FOV_ANGLE_UNITS = 'DEGREES' \begintext