PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 2009-03-04 NOTE = " This file is the current NH SDC 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 SDC 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_SDC_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 SDC Instrument Kernel ============================================================================== This instrument kernel (I-kernel) contains references to the mounting alignment, internal and FOV geometry for the New Horizons Student Dust Counter (SDC) instrument. 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 SDC I-kernel might have an entry as follows: TEXT_KERNEL_ID += 'NEWHORIZONS_SDC V1.0.0 22-FEBRUARY-2007 IK' | | | | | | | | KERNEL NAME <-------+ | | | | | V VERSION <-------+ | KERNEL TYPE | V ENTRY DATE SDC I-Kernel Version: \begindata TEXT_KERNEL_ID += 'NEWHORIZONS_SDC V1.0.1 4-AUGUST-2008 IK' NAIF_BODY_NAME += ( 'NH_SDC' ) NAIF_BODY_CODE += ( -98700 ) \begintext Version 1.0.1 -- August 4, 2008 -- Lillian Nguyen -- Fixed a typo in the text. Version 1.0.0 -- February 22, 2007 -- Lillian Nguyen -- Defined a celestial position angle reference vector. -- Promoting to version 1.0.0 denoting approval of kernel set by instrument teams. Version 0.0.1 -- January 15, 2006 -- Lillian Nguyen -- Draft Version. NOT YET APPROVED BY INSTRUMENT TEAM. -- Added field of view diagram. Version 0.0.0 -- January 15, 2006 -- Lillian Nguyen -- Draft Version. NOT YET APPROVED BY INSTRUMENT TEAM. References ---------------------------------------------------------- 1. New Horizons Spacecraft to SDC Interface Control Document, 7399-9050 Rev A. 2. ``Kernel Pool Required Reading'' 4. APL New Horizons web site, http://pluto.jhuapl.edu/spacecraft/overview.html. 5. E-mail exchange with David James (Laboratory for Atmospheric and Space Physics at the University of Colorado (LASP)), Jan. 26, 2006 - Feb. 1, 2006. 6. New Horizons Spacecraft Frames Kernel. 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 SDC instrument. The remainder of the name is an underscore character followed by the unique name of the data item. For example, the SDC boresight direction in the SDC frame (``NH_SDC'' -- see [6] ) is specified by: INS-98700_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. SDC description ---------------------------------------------------------- From [4]: ``The Student Dust Counter (SDC) will count and measure the sizes of dust particles along New Horizons' entire trajectory, which covers regions of interplanetary space never before sampled. Such dust particles are created by comets shedding material and Kuiper Belt Objects colliding with one another. The SDC is managed and was built primarily by students at the University of Colorado in Boulder, with supervision from professional space scientists.'' From [1]: ``The SDC's primary goal is to map the dust distribution from 1 to 50 AU in our solar system. Its secondary goal is to detect the putative dust ring/halo at Pluto. To do this, it uses detector patches consisting of permanently polarized polyvinylidine fluoride (PVDF) thin film. A dust grain that penetrates this film generates a de-polarization charge in the film whose amplitude is a function of the grain's mass and velocity. [This is adapted from an undated LASP document entitled "The Student Dust Counter Experiment"].'' SDC Field of View Parameters ---------------------------------------------------------- The SDC frame is defined such that the boresight is the instrument Z axis. From [5], the field of view is circular with a 180 degree angular separation. The field of view can also be described as the half-space given in instrument coordinates by Z > 0. In the following diagram, the field of view is the entire half-space to the right of the XY plane. Y ^ ins | | | | |-. 90 deg | ` +X (in) x---'-----------> +Z ins | ins | | | | | V Because the SDC field of view is circular, the FOV reference vector (keyword FOV_REF_VECTOR) is any vector with a component that lies in a plane normal to the field of view boresight. We chose the +Y axis of the instrument frame. These FOV values are given in the keywords below: \begindata INS-98700_FOV_FRAME = 'NH_SDC' INS-98700_FOV_SHAPE = 'CIRCLE' INS-98700_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-98700_FOV_CLASS_SPEC = 'ANGLES' INS-98700_FOV_REF_VECTOR = ( 0.0, 1.0, 0.0 ) INS-98700_FOV_REF_ANGLE = ( 90.0 ) INS-98700_FOV_ANGLE_UNITS = 'DEGREES' \begintext Also defined here is the celestial position angle reference vector. This vector defines the position angle, or angle from celestial north (and passing through celestial east) to the reference vector. \begindata INS-98700_REFERENCE_VECTOR = ( 1.0, 0.0, 0.0 ) \begintext