PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 2008-02-22 NOTE = " This file is the current NH ALICE SPICE Instrument Kernel with an attached PDS label prepended to it. It is only provided as a convenience to the user, As such, it is a trivial text file not meant to be relocatable with the archive which is why it does not have a detached PDS label. Furthermore, is not likely to be updated in a timely fashion as part of any SPICE kernel updates, and should therefore not be used as a SPICE kernel in any scientific investigation. - This file is included in the /DOCUMENT/ directory of most if not all volumes for this instrument as a convenience to the user because it documents the geometry of the ALICE instrument Field(s) Of View (FOV(s)). As such, and also because it is not likely to be updated in a timely fashion as - The original name of the source of this file was NH_ALICE_V###.TI where ### is a version number. - The format of this file, starting five lines after this TEXT OBJECT, is a SPICE Kernel Pool text file - The Instrument Kernel itself is (or will be) formally archived with the New Horizons SPICE dataset. - See the SPICE documentation for details of that format - http://naif.jpl.nasa.gov/ - Even without understanding that format, the Instrument Kernel, and especially its comments, are human readable. Comments are any line for which one of the following three statements is true: 1) The line is before the first data marker line in the file 2) The line is in a section of lines between a text marker line and a data marker line with no intervening text or data marker lines 3) The line is in a section of lines between the last text marker and the end of the file with no intervening text or data marker lines - a data marker line has the single token '\begindata' on it with all other characters on the line being whitespace - a text marker line has the single token '\begintext' on it with all other characters on the line being whitespace - N.B. Because padding and a carriage return have been added to each line of this file, it may or may not be functional as a valid SPICE kernel. " END_OBJECT = TEXT END ######################################################################## ##################### SPICE IK Starts after next line ################## ######################################################################## KPL/IK ALICE Instrument Kernel ============================================================================== This instrument kernel (I-kernel) contains references to the mounting alignment, internal and FOV geometry for the New Horizons ALICE UV imaging spectroscopy remote sensing package. Version and Date ---------------------------------------------------------- The TEXT_KERNEL_ID stores version information of loaded project text kernels. Each entry associated with the keyword is a string that consists of four parts: the kernel name, version, entry date, and type. For example, the ALICE I-kernel might have an entry as follows: TEXT_KERNEL_ID += 'NEWHORIZONS_ALICE V1.0.0 22-FEBRUARY-2007 IK' | | | | | | | | KERNEL NAME <-------+ | | | | | V VERSION <-------+ | KERNEL TYPE | V ENTRY DATE ALICE I-Kernel Version: \begindata TEXT_KERNEL_ID += 'NEWHORIZONS_ALICE V1.0.1 11-APRIL-2007 IK' NAIF_BODY_NAME += ( 'NH_ALICE_SOC' ) NAIF_BODY_CODE += ( -98100 ) NAIF_BODY_NAME += ( 'NH_ALICE_AIRGLOW' ) NAIF_BODY_CODE += ( -98101 ) \begintext Version 1.0.1 -- April 11, 2007 -- Lillian Nguyen -- Corrected the airglow field of view. Version 1.0.0 -- February 22, 2007 -- Lillian Nguyen -- Removed an incorrect annotation from the Alice Slit Design diagram and updated the remaining diagrams. -- Clarified that the entire Alice slit is visible through both Alice apertures and updated the field of view definitions appropriately. -- Noted that the standard acronym for the Solar Occultation Channel is SOCC. -- Promoting to version 1.0.0 denoting approval of kernel set by instrument teams. Version 0.0.2 -- October 4, 2006 -- Lillian Nguyen -- Removed the 3-letter frame NH_ALI and the Alice base frame. -- Renamed the SOC and Airglow instrument IDs to match the IDs in the frames kernel. Version 0.0.1 -- April 4, 2006 -- Lillian Nguyen -- Alice SOC and Airglow fields of view redefined according to orientation diagram received from instrument team. Version 0.0.0 -- December 1, 2005 -- Lillian Nguyen -- Draft Version. NOT YET APPROVED BY INSTRUMENT TEAM. References ---------------------------------------------------------- 1. ALICE Instrument Specification, 05310.02-ISPEC-01. 2. ``Kernel Pool Required Reading'' 3. Spacecraft to ALICE Interface Control Document (ICD), 7399-9046. 4. APL New Horizons web site, http://pluto.jhuapl.edu/spacecraft/overview.html. 5. New Horizons Spacecraft Frames Kernel. 6. New Horizons Mission Science Definitions (MSD), NH7399-9000v1.6. 7. New Horizons SOC to Instrument Pipeline ICD, 0531-SOCINST-01 Rev 0 Chg 0. 8. P-ALICE_Orientation_on_SC, received from Joel Parker in an e-mail dated Jan. 25, 2006; discussions with Dave Slater on Mar. 16 and 23, 2006, and e-mail exchange with Dave Slater on Mar. 28-29, 2006 regarding the diagram. 9. E-mail from Maarten Versteeg clarifying that the entire Alice slit is visible through both Alice apertures, received 2/22/2007, and from Joel Parker confirming that we should change the Alice fields of view to the entire lollipop-shaped slit, received 2/28/2007. 10. Telephone conversation with Hal Weaver about the Alice instrument. 11. E-mail from Andrew Steffl regarding Alice pointing offsets, received on 2/13/2007 and 3/22/2007. Contact Information ---------------------------------------------------------- Lillian Nguyen, JHU/APL, (443)-778-5477, Lillian.Nguyen@jhuapl.edu Implementation Notes ---------------------------------------------------------- This file is used by the SPICE system as follows: programs that make use of this instrument kernel must ``load'' the kernel, normally during program initialization. Loading the kernel associates data items with their names in a data structure called the ``kernel pool''. The SPICELIB routine FURNSH, CSPICE routine furnsh_c, and IDL routine cspice_furnsh load SPICE kernels as shown below: FORTRAN (SPICELIB) CALL FURNSH ( 'kernel_name' ) C (CSPICE) furnsh_c ( "kernel_name" ) ICY (IDL) cspice_furnsh, 'kernel_name' In order for a program or subroutine to extract data from the pool, the SPICELIB routines GDPOOL, GCPOOL, and GIPOOL are used. See [2] for details. This file was created and may be updated with a text editor or word processor. Naming Conventions ---------------------------------------------------------- All names referencing values in this I-kernel start with the characters `INS' followed by the NAIF New Horizons spacecraft ID number (-98) followed by a NAIF three digit ID code for the ALICE instrument. The remainder of the name is an underscore character followed by the unique name of the data item. For example, the airglow boresight direction in the airglow frame (``NH_ALICE_AIRGLOW'' -- see [5] ) is specified by: INS-98102_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. ALICE description ---------------------------------------------------------- From [4]: ``Alice is an ultraviolet imaging spectrometer that will probe the atmospheric composition of Pluto. A "spectrometer" is an instrument that separates light into its constituent wavelengths, like a prism, only better. An "imaging spectrometer" both separates the different wavelengths of light and produces an image of the target at each wavelength. Alice has two modes of operation: an "airglow" mode, which allows measurement of emissions from atmospheric constituents, and an "occultation" mode, when either the Sun or a bright star is viewed through the atmosphere producing absorption by the atmospheric constituents. The Alice occultation mode will be used just after New Horizons passes behind Pluto and looks back at the Sun through Pluto's atmosphere.'' From [1]: ``ALICE consists of a dedicated telescope that feeds a 0.15-m Rowland circle spectrograph with a spectral passband that spans the extreme and far ultraviolet (EUV/FUV) wavelength region of 520-1870 angstrom. Two separate input channels, the airglow and the solar occultation channels, direct light to the telescope. The airglow channel has an input aperture 40 mm x 40 mm with a boresight parallel to the RALPH boresight. The solar occultation channel (SOC) has a small 0.9 mm diameter aperture located on the telescope side of the ALICE housing with a boresight near parallel to the NH spacecraft's High Gain Antenna. A flat relay mirror at the center of the airglow channel directs the light entering the SOC aperture to the primary telescope mirror. The reduced SOC aperture limits the solar UV flux entering the telescope to prevent detector saturation at the spectrograph focal plane during solar occultation measurements. A microchannel plate (MCP) double-delay line (DDL) detector with dual, solar blind, UV-sensitive photocathodes (KBr/CsI), makes up the instrument's focal plane. . . . The detector electronics receive detected event pulses from the detector and provide a digital indication of the spatial and spectral location of each event being processed. The event processing electronics receive individual events and process them in one of two operational modes, pixel-list or histogram, based on commands from the IEM [Integrated Electronics Module]. Histogram mode is used to generate a two dimensional map of the pixel events with the magnitude of a particular pixel location indicating the number of times that pixel has been stimulated. Pixel-list mode is used to generate a time ordered record of detected events. Special periodic data markers (i.e. time hacks) are inserted in the list of pixels to provide a fixed time reference for the events. Pixel lists are accumulated continuously in a "ping-pong" memory with the data in one memory bank being transmitted to the IEM over the science telemetry channel while the other memory is used to continue data acquisition. The last set of pixel list data and the complete histogram data are transmitted to the IEM upon the command to stop data acquisition. . . . Field of View Airglow Mode The airglow slit opening shall have a FOV of 0.1 deg +/- 0.01 deg in the spectral dimension (slit width) by 4 deg +/- 0.1 deg in the spatial dimension (slit length). The center of the airglow slit shall be offset from the ALICE optical boresight by 1 +/- 0.1 deg. SOC Mode The SOC slit opening shall have a FOV of 2 deg +/- 0.1 deg in the spectral dimension (slit width) by 2 deg +/- 0.1 deg in the spatial dimension (slit length). The center of the SOC slit shall be offset from the ALICE optical boresight by 2 +/- 0.1 deg, and shall be a contiguous opening with the airglow slit. The boresight of the SOC FOV shall be aligned to the HGA (i.e. REX) boresight as specified in the Alice ICD (7399-9046). The co-alignment error between the ALICE SOC boresight and the REX boresight shall be as specified in the Alice ICD (7399-9046). The SOC aperture shall be sized to limit the detector output count rate to less than 30 kHz during the Pluto-Charon solar occultation. . . . ORIENTATION AIRGLOW CHANNEL APL shall align the ALICE Airglow channel to the identical requirements as RALPH/MVIC [25] section 6.5.2.2.1; namely: a. The boresight shall be aligned to the spacecraft -X axis to within 0.90 deg. b. The direction perpendicular to the 1024-element lines, and lying in the focal plane, shall be aligned at 90 deg +/- 0.90 to the scan axis of the spacecraft. {11/19/02} SOLAR OCCULTATION CHANNEL APL shall align the solar occultation channel (SOC) boresight to lie within 0.5 deg of a line in the Y-Z plane right-hand rotated by 2 deg around the X axis from the REX boresight. {11/19/02}'' From [3]: ``PERSI PERSI [Pluto Exploration Remote Sensing Investigation] consists of two separate instruments mounted close together on the New Horizons spacecraft: A. RALPH, the name (not an acronym) for the instrument consisting of: (1) MVIC, the Multispectral Visible Imaging Camera, including focal plane, electronics, telescope and mechanical structure, and (2) LEISA, the Linear Etalon Imaging Spectral Array, a focal plane assembly inside the MVIC structure that performs as an infrared (IR) mapping spectrometer. B. ALICE, the name (not an acronym) for PERSI's ultraviolet mapping spectrometer {8/8/02} . . . ALICE will be mounted directly to the +Z side of the spacecraft'' ALICE Field of View Parameters ---------------------------------------------------------- The Alice instrument has two apertures, the Solar Occulation Channel (SOC), and the Airglow opening. The SOC is also referred to as SOCC (Solar OCcultation Channel). Since the documents to which this kernel refers still use the SOC acronym for the Solar Occultation Channel, we continue to use it here as well, although SOCC is becoming the standard term [9]. Light travels through a lollipop-shaped slit described below for both the SOC and airglow apertures. Although [3], Rev A, defines the SOC field of view as only the 2.0 x 2.0 degree "box" portion of the lollipop-shaped slit and the Airglow field of view as the 0.1 x 4.0 degree "stem" of the lollipop-shaped slit, the complete lollipop shape is visible through both apertures [9]. The spectral resolution of airglow is degraded in the 2.0 x 2.0 degree "box" portion of the slit, but data is nevertheless still available in that portion of the slit. The 2.0 x 2.0 degree "box" portion of the slit is wider than the narrow "stem" portion to observe the sun during Solar Occulation Channel operations, but it is also possible for the sun to appear in the narrower "stem" portion [10]. Hence, the fields of view for both apertures have been defined here to be the entire lollipop-shaped slit even though they are defined differently in [3], Rev A. The diagram below (reproduced from Figure 19 of [3]) illustrates the ALICE field of view. The ALICE entrance slit design shows the 2.0 deg x 2.0 degree "box" portion of the lollipop-shaped slit and the 0.1 x 4.0 degree "stem" portion of the lollipop-shaped slit. The airglow channel feeds the SOC field of view along the entire 6.0 degree spatial dimension in the spacecraft Z direction. This diagram shows the actual position of the Alice slit on the spacecraft, using the spacecraft coordinate system. It is important to note that the entire 'lollipop' shape of the Alice slit is visible through both the SOC and the airglow apertures [9]. ALICE SLIT DESIGN _____________________4_________________________ | | | | | | | .---3-------. | | | | | | ^ | | | | | +Z | | | 2 | | | (deg) | | | | | | | | | | | | | | '---1-------' | | | | | | | | | | | |-----+-----+-----+----| |----+-----+-----+-----| -4 -3 -2 -1 | | 1 2 3 4 | | | | | -1| | | | | | | | | | | | -2| | | | | | | | | | | | -3'-' | | | | | | | |____________________-4_|_______________________| ----------------> +X (deg) for SOC +Y (deg) for airglow Note that because of the 2.0 degree instrument tip to rotate the +Y axis (the REX antenna boresight) to the center of the SOC field of view [8], the axis labeling for airglow in the diagram above is incorrect. The horizontal axis for airglow is not exactly +Y, as it is labeled, but actually +2.0 degrees rotated about spacecraft +X from spacecraft +Y. The same is true of the vertical axis for airglow. SOC Channel FOV Definition In SOC instrument coordinates, the boresight is the +Y axis, and the X and Z axes are close to the spacecraft X and Z axes, respectively [8]. A discussion of the SOC coordinate frame relative to the spacecraft frame can be found in [5]. The boresight of the SOC field of view is in the center of the 2.0 x 2.0 degree 'box' portion of the lollipop [9]. We use a polygon to describe the lollipop-shaped field of view, and will determine eight boundary corner vectors defining the vertices of the polygon. The SOC coordinate system, field of view center, and vertices V0 to V7 of the polygonal field of view are illustrated below. SOC Instrument ___ V1 _ V0 Coordinate System ^ | | | | | ^ +Z | | | | inst | | | | | | | | | | | | | | | x---------> | | | +Y (in) +X | | | inst inst | | | | 6 deg | | | | | | | | | | | | | | | ___ V3_____| |_____V6 | ^ | V2 V7 | | | | | | | | | | | 2 deg | x | <--- SOC boresight --- | | | | ^ | | | | | 1 deg _v_ _v_ |_____________| _v_ V4 V5 |<----------->| 2 deg The two diagrams below illustrate the calculations used to determine the X and Z components of the eight SOC boundary corner vectors. The Y component of each of the boundary corner vectors is arbitrarily set to 1 to simplify the calculations (i.e. for ease of computation, the field of view vectors are terminated at the plane Y = 1). View looking down the SOC X axis -------------------------------- ^ Z | inst | | z0, z1 o---------------o V0, V1 --- | /| | | | | | / | | | | | | / | | | | | | / | | | | | | / | | | | | | / | | | | | 4.0 deg | / | | | | | | / | | | | | | / | | | | | | / | | | | | | / | | | | | | / | | z2, z3, z6, z7 |--------------.o V2, V3, V6, V7 --- | / .-'| | | .-' | | | / .-' | | 1.0 deg | .-' | | |/-' | y=1 | X (out) o---------------+--------> Y (boresight) --- inst |`-. | inst | | `-. | | | `-. | | 1.0 deg | `-. | | | `-.| | z4, z5 o---------------o V4, V5 --- | | | v View looking up the SOC Z axis -------------------------------- ^ X | inst | | x5, x6 o---------------o V5, V6 --- | .'| | | .' | | | .' | | 0.95 deg | .' | | | .' | | x0, x7 o .' ___...o V0, V7 --- | .'.--''' | y=1 | 0.05 deg Z (in) x---------------+-------> Y (boresight) --- inst | `.`--...___ | inst | 0.05 deg x1, x2 o `. ```o V1, V2 --- | `. | | | `. | | | `. | | 0.95 deg | `. | | | `.| | x3, x4 o---------------o V3, V4 --- | | v From the upper diagram, we have (in degrees): tan(5.0) = z0 = z1 tan(1.0) = z2 = z3 = z6 = z7 tan(-1.0) = z4 = z5 From the lower diagram, we have (in degrees): tan(1.0) = x5 = x6 tan(0.05) = x0 = x7 tan(-0.05) = x1 = x2 tan(-1.0) = x3 = x4 Which yields the eight boundary corner vectors: V0 = [x0, y, z0] = [tan( 0.05), 1, tan( 5.0)] V1 = [x1, y, z1] = [tan(-0.05), 1, tan( 5.0)] V2 = [x2, y, z2] = [tan(-0.05), 1, tan( 1.0)] V3 = [x3, y, z3] = [tan(-1.0), 1, tan( 1.0)] V4 = [x4, y, z4] = [tan(-1.0), 1, tan(-1.0)] V5 = [x5, y, z5] = [tan( 1.0), 1, tan(-1.0)] V6 = [x6, y, z6] = [tan( 1.0), 1, tan( 1.0)] V7 = [x7, y, z7] = [tan( 0.05), 1, tan( 1.0)] The eight SOC boundary corner vectors are given in the field of view definition below, starting with V0. \begindata INS-98100_FOV_FRAME = 'NH_ALICE_SOC' INS-98100_FOV_SHAPE = 'POLYGON' INS-98100_BORESIGHT = ( 0.0, 1.0, 0.0 ) INS-98100_FOV_CLASS_SPEC = 'CORNERS' INS-98100_FOV_BOUNDARY_CORNERS = ( 0.000872664847521 1.000000000000000 0.087488663525924 -0.000872664847521 1.000000000000000 0.087488663525924 -0.000872664847521 1.000000000000000 0.017455064928218 -0.017455064928218 1.000000000000000 0.017455064928218 -0.017455064928218 1.000000000000000 -0.017455064928218 0.017455064928218 1.000000000000000 -0.017455064928218 0.017455064928218 1.000000000000000 0.017455064928218 0.000872664847521 1.000000000000000 0.017455064928218 ) \begintext Airglow Channel FOV Definition In airglow instrument coordinates, the boresight is the -X axis, and the +Y and +Z axes in the instrument frame are close to the spacecraft +Y and +Z axes, respectively [8]. A discussion of the airglow coordinate frame relative to the spacecraft frame can be found in [5]. Because the airglow frame has been rotated an additional 0.1 degree about the Y axis, the boresight of the airglow field of view is 0.1 degrees below the center of the 6.0 degree long slit portion of the lollipop in the diagram below [11]. We use a polygon to describe the lollipop-shaped field of view, and will determine eight boundary corner vectors defining the vertices of the polygon. The airglow coordinate system, field of view center, and vertices V0 to V7 of the polygonal field of view are illustrated below. Airglow Instrument ___ V1 _ V0 ___ Coordinate System ^ | | ^ | | | | ^ +Z | | | | | inst | | | | | | | | | | | | | | 3.1 deg | | | | | x---------> | | | | -X (in) +Y | | | | inst inst | | | | | 6 deg | | | | | | v | |x| <--- Airglow boresight --- | | | ^ | | | | | ___ V3_____| |_____V6 | 1.9 degree difference | ^ | V2 V7 | | between SOC boresight | | | | | and airglow boresight | | | | v | | 2 deg | * | --- | | | | ^ | | | | | 1.0 degree _v_ _v_ |_____________| _v_ V4 V5 Note that from [11], the airglow boresight is not at the center of the 6.0 degree long entrance slit; the airglow frame has been rotated by 0.1 degree (1/3 of one 0.3 degree detector row) about the Y axis so that when the boresight aims toward a point source, the spectrum falls onto a single detector row (or as close as possible). The eight airglow boundary corner vectors can be determined using a similar calculation as was done for the SOC, but since the airglow field of view shape is identical to the SOC shape, the airglow field of view can be determined by rotating the boundary corner vectors of the SOC field of view into the airglow frame, then shifting the Z coordinate of each the vectors down by 1.9 degrees so that the airglow boresight is in the center of the Alice slit, rather than in the center of the 'box' portion of the slit as in the SOC definition. The 1.9 degree shift is illustrated above. The coordinate transformation taking vectors in the SOC instrument frame to vectors in the airglow instrument frame is as follows: SOC Airglow X Y Y -X Z Z The above rotation yields the following intermediate set of boundary corner vectors in the airglow frame: V0 = [-1, tan( 0.05), tan( 5.0)] V1 = [-1, tan(-0.05), tan( 5.0)] V2 = [-1, tan(-0.05), tan( 1.0)] V3 = [-1, tan(-1.0), tan( 1.0)] V4 = [-1, tan(-1.0), tan(-1.0)] V5 = [-1, tan( 1.0), tan(-1.0)] V6 = [-1, tan( 1.0), tan( 1.0)] V7 = [-1, tan( 0.05), tan( 1.0)] The 1.9 degree translation in each of the Z coordinates yields the airglow boundary corner vectors: V0 = [-1, tan( 0.05), tan( 3.1)] V1 = [-1, tan(-0.05), tan( 3.1)] V2 = [-1, tan(-0.05), tan(-0.9)] V3 = [-1, tan(-1.0), tan(-0.9)] V4 = [-1, tan(-1.0), tan(-2.9)] V5 = [-1, tan( 1.0), tan(-2.9)] V6 = [-1, tan( 1.0), tan(-0.9)] V7 = [-1, tan( 0.05), tan(-0.9)] The eight airglow boundary corner vectors are given in the field of view definition below, starting with V0. \begindata INS-98101_FOV_FRAME = 'NH_ALICE_AIRGLOW' INS-98101_FOV_SHAPE = 'POLYGON' INS-98101_BORESIGHT = ( -1.0, 0.0, 0.0 ) INS-98101_FOV_CLASS_SPEC = 'CORNERS' INS-98101_FOV_BOUNDARY_CORNERS = ( -1.000000000000000 0.000872664847521 0.054158064087029 -1.000000000000000 -0.000872664847521 0.054158064087029 -1.000000000000000 -0.000872664847521 -0.015709255323665 -1.000000000000000 -0.017455064928218 -0.015709255323665 -1.000000000000000 -0.017455064928218 -0.050657814643101 -1.000000000000000 0.017455064928218 -0.050657814643101 -1.000000000000000 0.017455064928218 -0.015709255323665 -1.000000000000000 0.000872664847521 -0.015709255323665 ) \begintext