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.
Back to Table of Contents
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.
Back to Table of Contents
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.
Back to Table of Contents
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.
Back to Table of Contents
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.
Back to Table of Contents
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.
Back to Table of Contents
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.
Back to Table of Contents
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.
Back to Table of Contents
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.
Back to Table of Contents
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.
Back to Table of Contents
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.
Back to Table of Contents
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.
Back to Table of Contents
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.
Back to Table of Contents
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
Back to Table of Contents
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
Back to Table of Contents
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
Back to Table of Contents
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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