The OSIRIS-REx SPICE Data Archive
========================================================================

   Last update: November 18, 2019


Introduction
============

   This document describes the OSIRIS-REx SPICE archive, containing
   observation geometry and other ancillary data in the form of SPICE
   System kernel files for the OSIRIS-REx spacecraft and its
   instruments and targets. It describes the archive directory
   structure, kernels included in the archive, their naming
   conventions, and provides pointers to the SPICE software and
   documentation.


Table of Contents
=================

   Introduction
   Table of Contents
   Overview
   Errata
   Archive Contents
   Kernel Types
   Archived Kernel Details
      SPK Files
      PCK Files
      IK Files
      CK Files
      LSK Files
      SCLK Files
      FK Files
      DSK Files
      MK Files
   File Formats
   SPICE Software and Documentation
   Contact Information
   Cognizant Persons



Overview
========
 
   This archive includes the complete set of OSIRIS-REx SPICE data files
   (kernel files), which can be accessed using SPICE software. The
   SPICE data contain geometric and other ancillary information needed
   to recover the full value of science instrument data. In particular
   SPICE kernels provide spacecraft and planetary ephemerides,
   spacecraft and instrument orientation, instrument mounting
   alignments, and data needed for relevant time conversions. Data in
   the SPICE kernel files must be accessed using the software called
   the SPICE Toolkit produced and distributed by the Navigation and
   Ancillary Information Facility (NAIF) Node of the Planetary Data
   System.

   This archive includes data covering from OSIRIS-REx launch, 2016-09-08,
   through the end time of the latest spacecraft orientation file
   supplied in the archive. Until the end of the spacecraft lifespan
   this archive will be accumulating with new data added according to
   the project archiving plan.

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Errata ====== 1. This document is a simple HTML document. Providing documents in a simple mark-up format was allowed by earlier versions of the PDS4 Standards but became prohibited in later versions starting summer 2015. Since the document was compliant at the time when its first version was released, it will continue to exist in the archive as an HTML document. 2. All IK files (except the OCAMS IK orx_ocams_v07.ti) included in the archive are placeholder versions containing only Field-Of-View (FOV) definitions. More complete versions of these IKs will be added to the archive in subsequent releases.

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Archive Contents =============== Files in this archive are organized into a set of subdirectories below the top-level directory. The following diagram shows the structure and content of these directories. The directory names are enclosed in square brackets ([]). [top-level-directory] | |- bundle_orex_spice_v*.xml Bundle PDS4 label, one or more versions. |- readme.txt Bundle top-level readme file. | |-[spice_kernels] Directory containing SPICE kernels. | | | |- collection_spice_kernels_v*.xml PDS4 labels for Spice Kernels collections. | |- collection_spice_kernels_inventory_v*.tab | | Spice Kernels collections' inventories. | | | |-[ck] Directory containing CK files. | | | | | |-- *.bc Binary CK files. | | +-- *.xml PDS4 labels for CK files. | | | |-[dsk] Directory containing DSK files. | | | | | |-- *.bds Binary DSK files. | | +-- *.xml PDS4 labels for DSK files. | | | |-[fk] Directory containing FK files. | | | | | |-- *.tf Text FK files. | | +-- *.xml PDS4 labels for FK files. | | | |-[ik] Directory containing IK files. | | | | | |-- *.ti Text IK files. | | +-- *.xml PDS4 labels for IK files. | | | |-[lsk] Directory containing LSK files. | | | | | |-- *.tls Text LSK files. | | +-- *.xml PDS4 labels for LSK files. | | | |--[mk] Directory containing MK files. | | | | | |-- *.tm Text Meta-kernel files. | | +-- *.xml PDS4 labels for MK files. | | | |-[pck] Directory containing PCK files. | | | | | |-- *.tpc Text PCK files. | | +-- *.xml PDS4 labels for PCK files. | | | |-[sclk] Directory containing SCLK files. | | | | | |-- *.tsc Text SCLK files. | | +-- *.xml PDS4 labels for SCLK files. | | | +-[spk] Directory containing SPK files. | | | |-- *.bsp Binary SPK files. | +-- *.xml PDS4 labels for SPK files. | +-[document] Directory containing documents. | |- collection_document_v*.xml PDS4 labels for document collections. |- collection_document_inventory_v*.tab | Document collections' inventories. | |- spiceds_v*.html This file and its earlier versions. +- spiceds_v*.xml PDS4 labels for this file and its earlier versions.

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Kernel Types ============ Different SPICE kernel types are used to store different kinds of ancillary data. SPK (Spacecraft Planet Kernel) files contain ephemerides (position and velocity) for spacecraft, planets, satellites, comets and asteroids as well as for moving or fixed spacecraft and instrument structures. SPK files are located under the spice_kernels/spk directory of this archive. PCK (Planetary Constants Kernel) files contain certain physical, dynamical and cartographic constants for target bodies, such as size and shape specifications, and orientation of the spin axis and prime meridian. PCK files are located under the spice_kernels/pck directory of this archive. IK (Instrument Kernel) files contain instrument parameters relevant for computing an instrument's geometry such as field-of-view definitions, CCD and optical distortion characteristics, and internal timing parameters. IK files are located under the spice_kernels/ik directory of this archive. CK (C-matrix Kernel) files contain time varying orientations for spacecraft, spacecraft structures, and articulating science instruments. CK files are located under the spice_kernels/ck directory of this archive. LSK (Leapseconds Kernel) files contain the leapseconds and the values of other constants required to perform a transformation between Universal Time Coordinated (UTC) and Ephemeris time (ET), which is also known as Barycentric Dynamical Time (TDB). LSK files are located under the spice_kernels/lsk directory of this archive. SCLK (Spacecraft Clock Kernel) files contain on-board clock calibration data required to perform a transformation between Ephemeris time (ET) and spacecraft on-board time (SCLK). SCLK files are located under the spice_kernels/sclk directory of this archive. FK (Frame definitions Kernel) files contain information required to define reference frames, sources of frame orientation data and connections between these frames and other frames supported within the SPICE system. The science instrument frame definitions provided in the FK files include mounting alignment information for the instruments. FK files also frequently contain NAIF name/ID mappings for bodies, spacecraft instruments and structures, and for DSK surfaces. FK files are located under the spice_kernels/fk directory of this archive. DSK (Digital Shape Kernel) files contain detailed shape models for extended objects such as planets, natural satellites, asteroids, and comet nuclei. DSK files are located under the spice_kernels/dsk directory of this archive. MK (Meta-Kernel) files list sets of related SPICE kernels that should be used together, providing an easy way to make data from these kernel sets available to a SPICE-based application by loading meta-kernels into the program using the high level SPICE data loader routine FURNSH. MK files are located the spice_kernels/mk directory of this archive. Archived Kernel Details ======================= The subsections below provide details, such as file naming conventions and specific details, for each of the kernel types included in this archive.

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SPK Files SPK (Spacecraft Planet Kernel) files contain ephemerides (position and velocity) for spacecraft, planets, satellites, comets and asteroids as well as for moving or fixed spacecraft and instrument structures. This archive includes binary SPK files containing the following kinds of ephemeris data: - planetary ephemeris SPKs These SPKs contain ephemeris data for the Solar System planet barycenters, and Sun, Mercury, Venus, Earth, and Moon. They are produced by the JPL Solar System Dynamics group and are named DEXXX, e.g. DE424. - Asteroid Bennu ephemeris SPKs These SPKs contain ephemeris data for asteroid Bennu. They are produced by the OSIRIS-REx science team. - reconstructed spacecraft trajectory SPKs. These SPKs contain the reconstructed OSIRIS-REx spacecraft trajectory determined by the OSIRIS-REx Flight Dynamics (FDS) team, KinetX. - structures SPKs These SPKs contain fixed locations of selected spacecraft structures and science instruments. They are produced by NAIF based on OSIRIS-REx engineering documentation. The SPK files are provided under the spice_kernels/spk directory and are named according to the following schemas: - planetary ephemeris SPKs deVVVs.bsp where VVV is the ephemeris version s (optional) indicates that the original file coverage was shortened to reduce the file size. - Asteroid Bennu ephemeris SPKs bennu_*_vV.bsp where V is the version; the file with the latest version supersedes all similarly named files with earlier versions. - reconstructed spacecraft trajectory SPKs orx_YYMMDD_YYMMDD_yymmdd_odDDD_vV.bsp where YYMMDD are the file coverage start and stop dates yymmdd is the data-cutoff (DCO) date, which is the stop date of the reconstructed part of the file. WARNING: the trajectory beyond this date is predicted and may differ substantially from from the actual flown trajectory. DDD is the three digit ID of the orbit determination (OD) solution. V is the version; the file with the latest version supersedes all similarly named files with earlier versions. - structures SPKs orx_struct_vVV.bsp where VV is the version; the file with the latest version supersedes all similarly named files with earlier versions. The most detailed description of the data in each SPK file is provided in metadata included inside the comment area of the file. This information can be viewed using the utility program COMMNT included in the NAIF Toolkit.

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PCK Files PCK (Planetary Constants Kernel) files contain certain physical, dynamical, and cartographic constants for target bodies, such as size and shape specifications, and orientation of the spin axis and prime meridian. This archive includes generic text PCK files produced by NAIF, containing data from the reports of the IAU Working Group on Cartographic Coordinates and Rotational Elements, and asteroid Bennu text PCK files produced by NAIF from input provided by the OSIRIS-REx science team. The PCK files are provided under the spice_kernels/pck directory and are named according to the following schemas: - generic text PCKs pckVVVVV.tpc where VVVVV is the version; the file with the largest number is the latest, but the user of PCK data must decide if the latest version, or an earlier version, is appropriate for his/her analysis task. - asteroid Bennu text PCK files bennu_vVV.tpc where VV is the version; the file with the largest number is the latest, but the user of PCK data must decide if the latest version, or an earlier version, is appropriate for his/her analysis task. The most detailed description of the data in a text PCK file is provided in metadata included inside the description areas of the file. This information can be viewed using any text editor program.

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IK Files IK (Instrument Kernel) files contain instrument parameters relevant for computing an instrument's observation geometry such as field-of-view definitions, CCD and optical distortion characteristics, and internal timing parameters. This archive includes text IK files for all OSIRIS-REx science instruments and for selected OSIRIS-REx spacecraft structures (antennae, star trackers, etc.) These IKs were created by NAIF in cooperation with the OSIRIS-REx instrument teams. The IK files are provided under the spice_kernels/ik directory and are named according to the following scheme: - instrument and antennae IK files orx_NAME_vVV.ti where NAME is the instrument acronym lidar navcam ocams ola otes ovirs rexis stowcam struct (for antennae, star trackers, etc.) VV is the version; the file with the latest version supersedes all similarly named files with earlier versions, but the SPICE user must decide if the latest version, or an earlier version, is appropriate for his/her analysis task. The most detailed description of the data in a text IK file is provided in metadata included inside the description area of the file. This information can be viewed using any text editor program.

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CK Files CK (C-matrix Kernel) files contain time varying orientations for spacecraft, articulating spacecraft structures, and articulating science instruments. This archive includes binary CK files containing the following kinds of orientation data: - reconstructed spacecraft orientation CKs These CKs created by NAIF contain the reconstructed OSIRIS-REx spacecraft attitude determined on-board and downlinked in spacecraft telemetry. - reconstructed Solar Array (SA) orientation CKs These CKs created by NAIF contain the reconstructed OSIRIS-REx SA gimbal angles measured on-board and downlinked in spacecraft telemetry. - reconstructed OLA mirror orientation CKs These CKs created by the OLA science team at Applied Physics Laboratory, Johns Hopkins University, contain the reconstructed OSIRIS-REx OLA mirror orientation computed from OLA mirror azimuth and elevation angles from the corresponding OLA Level 1 (L1) product records. - reconstructed Touch-And-Go Sample Arm Mechanism (TAGSAM) orientation CKs These CKs created by NAIF contain the reconstructed OSIRIS-REx TAGSAM gimbal angles measured on-board and downlinked in spacecraft telemetry. The CK files are provided under the spice_kernels/ck directory and are named according to the following schemes: - spacecraft, solar array, and TAGSAM CKs orx_NAME_TYPE_YYMMDD_yymmdd_vVV.bc where NAME is the structure acronym sc for spacecraft sa for SA tag for TAGSAM TYPE is the data type rel for reconstructed, long rec for reconstructed YYMMDD is the file coverage start date yymmdd is the file coverage stop date VV is the version; the file with the latest version supersedes all similarly named files with earlier versions. - OLA CKs orx_ola_YYMMDD_scil2idxxxxx[_vVV].bc where YYMMDD is the file coverage start date for the first record in the associated OLA Level 2 (L2) science product scil2 identifies the CK file as being associated with an OLA L2 science data product idxxxxx denotes the 5 digit unique id (xxxxx) for the given YYMMDD. This handles the case where the scan ID may be rolled over; the combination of YYMMDD and xxxxx is enough to uniquely identify a given CK or an OLA science product. VV is the version, optional and omitted for version 01 products; the file with the latest version supersedes all similarly named files with earlier versions. The most detailed description of the data in each CK file is provided in metadata included inside the comment area of the file. For the OLA CKs covering from March 2019 this description also provides a detailed algorithm of how OLA mirror orientation was computed from OLA mirror azimuth and elevation angles. This information can be viewed using the utility program COMMNT included in the NAIF Toolkit.

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LSK Files LSK (Leapseconds Kernel) files contain the leapseconds and the values of other constants required to perform a transformation between Universal Time Coordinated (UTC) and Ephemeris time (ET), also known as Barycentric Dynamical Time (TDB). This archive includes generic text LSK files produced by NAIF, containing leapsecond information based on the IERS announcements. The LSK files are provided under the spice_kernels/lsk directory and are named according to the following scheme: - generic text LSKs naifVVVV.tls where VVVV is the version; the file with the latest version supersedes all similarly named files with earlier versions. The most detailed description of the data in a text LSK file is provided in metadata included inside the description area of the file. This information can be viewed using any text editor program.

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SCLK Files SCLK (Spacecraft Clock Kernel) files contain on-board clock calibration data required to perform a mapping between Ephemeris time (ET) and spacecraft on-board time (SCLK). This archive includes text SCLK files containing correlation data for the main OSIRIS-REx on-board clock, created by NAIF from the SCLK_SCET files generated by the Spacecraft Team, LMCO. The SCLK files are provided under the spice_kernels/sclk directory and are named according to the following scheme: - main OSIRIS-REx spacecraft clock SCLK files orx_sclkscet_VVVVV.tsc where VVVVV is the version; the file with the latest version supersedes all similarly named files with earlier versions. The most detailed description of the data in a text SCLK file is provided in metadata included inside the description area of the file. This information can be viewed using any text editor program.

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FK Files FK (Frame definitions Kernel) files contain information required to define reference frames, sources of frame orientation data and connections between these frames and other frames supported within the SPICE system. The science instrument frame definitions provided in the FK files include mounting alignment information for the instruments. FK files also frequently contain NAIF name/ID mappings for bodies, spacecraft instruments and structures, and for DSK surfaces. This archive includes text FK files defining reference frames for the OSIRIS-REx spacecraft, its structures, and science instruments. These FKs were produced by NAIF using the spacecraft and instrument design documentation as well as actual instrument alignment values determined pre-launch and as the result of in-flight calibrations. It also includes text FK files defining surface name/ID mappings for the surfaces provided in Bennu DSK files. These FKs were produced by the OSIRIS-REx Altimetry Working Group (AltWG). The FK files are provided under the spice_kernels/fk directory and are named according to the following scheme: - OSIRIS-REx mission FK files orx_vVV.tf where VV is the version; the file with the latest version supersedes all similarly named files with earlier versions, although a SPICE user might decide decide to use an earlier version if trying to be consistent with some earlier computed results. - OSIRIS-REx DSK surface name/ID mapping FK files orx_shape_vVV.tf where VV is the version; the file with the latest version supersedes all similarly named files with earlier versions, although a SPICE user might decide decide to use an earlier version if trying to be consistent with some earlier computed results. The most detailed description of the data in a text FK file is provided in metadata included inside the description area of the file. This information can be viewed using any text editor program.

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DSK Files DSK (Digital Shape Kernel) files contain detailed shape models for extended objects such as planets, natural satellites, asteroids, and comet nuclei. This archive includes binary DSK files containing digital shape data for the OSIRIS-REx mission target asteroid Bennu. These DSKs were produced by the OSIRIS-REx science team. The DSK files are provided under the spice_kernels/dsk directory and are named according to the following scheme: - asteroid Bennu DSK files bennu_C_RRRRRmm_SSS_obj_LLLLDGGGGG_vVVV.bds where C is the spacial coverage token: g global coverage; if the file contains a complete closed body surface l local (partial) coverage; if the single file contains only a part of the a complete body surface, whether as part of a global tileset or just a small disjoint region RRRRR is the average vertex spacing, in mm SSS is the shape model source: spc Stereo Photoclinometry ola OLA tru Combined, true solution LLLLD is the center latitude of the file LLLL latitude in degrees; implicit decimal point after the second digit; D n for North or s for South; 0000n for files with global coverage GGGGG is the center longitude of the file; in degrees; implicit decimal point after the third digit; 00000 for files with global coverage VVV is the internal OSIRIS-REx version number; only selected fully validated models are included in the archive. The most detailed description of the data in each DSK file is provided in metadata included inside the comment area of the file. This information can be viewed using the utility program COMMNT included in the NAIF Toolkit.

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MK Files Meta-kernel (MK) files (a.k.a 'furnsh' files) provide lists of the archived kernels included in this archive suitable for loading into a SPICE-based application via the high level SPICE data loader routine FURNSH. Using meta-kernels makes it easy to load, with one call, a comprehensive SPICE data collection for a given period. The text MK files are provided under the spice_kernels/mk directory and are named according to the following scheme: - OSIRIS-REx yearly MK files orx_YYYY_vVV.tm - OSIRIS-REx yearly MK files without OLA CKs orx_noola_YYYY_vVV.tm where YYYY is the year covered by the kernels listed in the MK VV is the version; the file with the latest version supersedes all similarly named files with earlier versions. Multiple versions of a meta-kernel for the same year may exist if new kernels were added to the archive in a later release and the meta-kernel for that year had to be updated to incorporate them. The reasons for adding new kernels include (but are not limited to) adding new kinds of kernels, adding new versions of existing kernels containing more complete or more accurate data, and adding new versions of existing kernels superseding the existing kernels that had errors. If more than one meta-kernel file for the same year is present, then the file with the latest version number supersedes all earlier versions. The latest yearly meta-kernels can be loaded together sorted by year to provide coverage for more than one year. (Note that on some environments loading too many kernels at once may slow down data access.) Although the meta-kernels were created such that on a UNIX workstation they can be loaded into a SPICE-based application directly from the directory in which they reside -- because the PATH_VALUES keyword is set to '..' and '/' is used as the path delimiter -- it is recommended that users make local copies of these files and update the PATH_VALUES keyword in each of them to point to the actual location of the archive's 'spice_kernels' directory on their system. Additional changes including replacing '/' and '\' in all path specifications and converting UNIX line terminators to terminators native to the user's system may be required to use these meta-kernels on non-UNIX workstation. The following guidelines were followed to pick and set priority -- determined by the order in which the kernel files are listed, with the latest one taking precedence -- for the kernel files included in the orx_YYYY_vVV.tm meta-kernels: - the latest archived versions of LSK, PCKs, SCLK, IKs, FK, generic SPKs, and fixed offset SPKs were included - the latest reconstructed OSIRIS-REx FDS SPKs were included - the latest reconstructed spacecraft, solar array, and TAGSAM CKs were included - the latest reconstructed OLA CKs were included - no DSKs were included The orx_noola_YYYY_vVV.tm MKs include exactly same set of kernels as the orx_YYYY_vVV.tm MKs while omitting OLA CKs that are very large in size, have many segments, and are not needed for applications that don't seek computing the actual OLA view geometry. It is recommended any such applications use this set of MKs and, if desired to reduce the total size of the archive, delete all OLA CKs (spice_kernels/ck/orx_ola_*.bc) from the archive. Additional description of the kernels sets listed in a text MK file is provided in metadata included inside the description area of the file. This information can be viewed using any text editor program.

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File Formats ============ All text documents and other meta information files such as descriptions, detached PDS4 labels, and inventory tables are stream format files, with a carriage return (ASCII 13) and a line feed character (ASCII 10) at the end of the records. This allows the files to be read by most operating systems. The text kernel files in this archive -- LSKs, PCKs, SCLKs, IKs, and FKs -- are UNIX text files, with a line feed character (ASCII 10) at the end of the line, and binary kernels files -- SPKs, CKs, and DSKs -- are IEEE LSB binary files. While data files in this archive can be used 'as is' with SPICE toolkits for the majority of supported environments, converting the files to the binary or text format native to the user's computer may be required for use of the data with FORTRAN toolkits on incompatible environments. Refer to the documentation provided with the SPICE Toolkit to find out whether conversion is needed in each specific case. NAIF provides a tool (BINGO) that can convert either binary or text kernels from one format to another. This means that text files can have their line terminator changed and binary files can be converted to the native format of the platform of interest. BINGO is available from the utilities page at the NAIF Node of the PDS: http://naif.jpl.nasa.gov/naif/utilities.html

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SPICE Software and Documentation ================================ The latest SPICE Toolkit for a variety of computer platforms, additional utility programs, documentation, tutorials, and hands-on SPICE-focused programming lessons are available at the NAIF Node of the PDS: http://naif.jpl.nasa.gov specifically: Toolkit: http://naif.jpl.nasa.gov/naif/toolkit.html Utilities: http://naif.jpl.nasa.gov/naif/utilities.html Tutorials: http://naif.jpl.nasa.gov/naif/tutorials.html Lessons: http://naif.jpl.nasa.gov/naif/lessons.html

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Contact Information =============================== PDS Navigation and Ancillary Information Facility (NAIF), MAIL STOP 301-121 Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Drive Pasadena, CA, 91109-8099 818-354-8136 WWW Site: http://naif.jpl.nasa.gov

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Cognizant Persons ================= This archive was produced by Boris Semenov, Planetary Data System Navigation and Ancillary Information Facility Node, Jet Propulsion Laboratory, Pasadena, California. End of OSIRIS-REx SPICE archive description.

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