The DART SPICE Data Archive
========================================================================
Last update: December 5, 2022
Introduction
============
This document describes the DART SPICE archive, containing
observation geometry and other ancillary data in the form of SPICE
System kernel files for the DART spacecraft and its instruments and
targets, and for the LICIACube (LICIA) spacecraft and its instruments and
structures. 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
Miscellaneous Files
Checksum Files
File Formats
SPICE Software and Documentation
Contact Information
Cognizant Persons
Overview
========
This archive includes the complete set of DART and LICIA 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 DART launch, 2021-11-18,
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 using HTML documents was compliant at the time when a
similar document was first provided in the MAVEN PDS4 archive and
since NAIF strives to make bundle description document format and
style consistent across all archives, this document continues
to exist in this archive as an HTML document.
2. The XML labels of the ancillary products have the reference_type
attribute of the Internal_Reference association within the
Reference_List class of the Context_Area class pointing to the latest
archive description document set to "ancillary_to_data" which is not
correct. The correct value "ancillary_to_document" could not be used
in these labels because it is not available in the PDS4 information
model (IM) 1.5.0.0 used by this archive. This value was added to IM
only in the version 1.14.0.0.
3. CK files generated for the DART spacecraft contain
several gaps in time coverage for different known reasons. These
gaps may be eliminated in the next release.
4. SPK file didymos_system_s501_v01.bsp has a 1 ms gap in time
coverage. This gap may be eliminated in the next release.
5. The SPK dart_2022_231_2022_269_rec_v01.bsp, reconstructed from telemetry,
and the SPK dart_2022_269_2022_269_spc_v01.bsp, reconstructed from
Stereophotoclinometry, differ by approximately 2.7 km down-track distance
and 0.45 seconds at the impact time of 2022-09-26T23:14:24.183 UTC. This
version of the _rec_ SPK did not consider the final four hours of imaging,
but future versions will include them.
6. The impact time according to SPK dart_2022_269_2022_269_spc_v01.bsp is
2022-SEP-26 23:14:24.164 UTC. This was found by determining the closest
approach of DART to the impact site SPK dart_2022_269_2099_001_imp_v01.bsp.
This differs from the impact time of 2022-SEP-26 23:14:24.183 UTC from
dart_2022_269_2022_269_spc_v01.bsp and didymos_system_s501_v01.bsp by ~19
milliseconds. Most, but not all, of this discrepancy is the travel time
of DART from the surface of Dimorphos to its center.
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_dart_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.
|
|-+-[miscellaneous] Directory miscellaneous files.
| |
| |- collection_miscellaneous_v*.xml PDS4 labels for miscellaneous collections.
| |- collection_miscellaneous_inventory_v*.tab
| | Miscellaneous collections' inventories.
| |
| +-[checksum] Directory containing checksum files.
| |
| |-- *.tab Text checksum files.
| +-- *.xml PDS4 labels for checksum 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 under 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.
- Asteroids Didymos and Dimorphos ephemeris SPKs
These SPKs contain ephemeris data for the Didymos System. They
are produced by the JPL Solar System Dynamics group.
- DART structure SPK
SPK containing fixed structures on the DART spacecraft
(e.g. solar arrays, LICIACube mount, thrusters).
- reconstructed spacecraft trajectory SPKs.
These SPKs contain the reconstructed DART spacecraft
trajectory determined by the DART Mission Design Team.
The SPK files are provided under the spice_kernels/spk
directory and are named according to the following schemes:
- 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.
- Jovian system ephemeris SPKs
jupVVV.bsp
where
VVV is the ephemeris version.
- Didymos system ephemeris SPKs
didymos_barycenter_sSSS_vVV.bsp
where
SSS is the solution version.
VV is the file version; the file with the latest
version supersedes all similarly named files
with earlier versions.
- Didymos and Dimorphos ephemeris SPKs
didymos_system_sSSS_vVV.bsp
where
SSS is the solution version.
VV is the file version; the file with the latest
version supersedes all similarly named files
with earlier versions.
- DART structure SPK
dart_struct_vVV.bsp
where
VV is the file version; the file with the latest
version supersedes all similarly named files
with earlier versions.
- reconstructed trajectory SPKs
SC_YYYY_DDD_YYYY_DDD_TYPE_vVV.bsp
where
SC is the spacecraft name, either "dart" or "licia".
YYYY is the file coverage start and stop year
DDD is the file coverage start and stop day of year
TYPE is the data type
imp impact kernel; this is the fixed
position of the DART impact site on
Dimorphos
rec reconstructed trajectory
spc derived from stereophotoclinometry
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 text and binary PCK files containing the following
kind of data:
- generic text PCKs
These PCKs contain data from the reports of the IAU Working
Group on Cartographic Coordinates and Rotational Elements.
The generic text PCK version 00010 contains data from the 2009
report. Produced by NAIF, JPL.
- Didymos system text PCK files
These PCKs contain for the Didymos system provided by the DART
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.
- Didymos system text PCK files
didymos_system_VV.tpc
where
VV is the file 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 PCK 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
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 the DRACO camera on board DART and
for the Luke and Leia cameras on board LICIA.
The IK files are provided under the spice_kernels/ik
directory and are named according to the following scheme:
- instrument and antennae IK files
SC_NAME_VVV.ti
where
SC is the spacecraft name, either "dart" or "licia".
NAME is the instrument acronym:
draco Didymos Reconnaissance and Asteroid Camera
for OpNav (DRACO)
pl LICIA Luke and Leia combined payload
VVV 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 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:
- DART spacecraft, high gain antenna, and solar array CKs and
These CKs contain reconstructed and predicted DART spacecraft
solar arrays, and high gain antenna orientation information.
- LICIA spacecraft CKs
These CKs contain reconstructed and predicted LICIA spacecraft
orientation information.
The CK files are provided under the spice_kernels/ck
directory and are named according to the following scheme:
- DART spacecraft, high gain antenna, and solar array CKs and LICIA
spacecraft CKs
SC_YYYY_DDD_YYYY_DDD_TYPE_vVV.bc
where
SC is the spacecraft name, either "dart" or "licia".
YYYY is the start/end year
DDD is the start/end day of year
TYPE is the data type
rec reconstructed attitude from telemetry
spc derived from stereophotoclinometry
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 CK 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
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 DART on-board clock and the LICIA on-board clock.
The SCLK files are provided under the spice_kernels/sclk
directory and are named according to the following scheme:
- spacecraft clock SCLK files
SC_sclk_VVVV.tsc
where
SC is the name of the spacecraft in lower case; either
"dart" or "licia"
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 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.
This archive includes text FK files defining reference frames for
the DART 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 reference frames and surface
name/ID mappings for the Didymos system.
The FK files are provided under the spice_kernels/fk
directory and are named according to the following scheme:
- Spacecraft FK files
SC_VVV.tf
where
SC is the name of the spacecraft in lower case; either
"dart" or "licia"
VVV 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.
- Didymos system FK files
didymos_system_VVV.tf
where
VVV 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 DART mission target asteroids Didymos and Dimorphos. These DSKs
were produced by the DART Altimetry Working Group.
The DSK files are provided under the spice_kernels/dsk
directory and are named according to the following scheme:
- asteroid Didymos/Dimorphos DSK files
BODY_C_RRRRRmm_spc_LLLLDGGGGG_vVVV.bds
where
BODY is the body name in lower case; either "didymos" or
"dimorphos"
C is the spatial 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 stereophotoclinometry
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 version number.
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:
- DART MK files
dart_vVV.tm
where
VV is the version; the file with the latest
version supersedes all similarly named
files with earlier versions.
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 dart_vVV.tm meta-kernels:
- the latest archived versions of LSK, PCK, and each kind of
SCLKs, IKs, FKs, SPKs, and CKs were included
- no DSKs were included
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
Miscellaneous Files
===================
Miscellaneous files provide value added elements that are outside the
scope of the PDS archive requirements. Miscellaneous files included in
this archive are currently limited to checksum files.
The subsection below provides details for these files.
Back to Table of Contents
Checksum Files
A checksum file provides a table of MD5 checksums for all files in the
archive as of a particular archive (bundle) version, including
checksums for all previous checksums files and their labels but
excluding the checksum for the checksum file itself and its label.
The checksum files are provided under the miscellaneous/checksum
directory and are named according to the following scheme:
- DART checksum files
checksum_vVVV.tab
where
VVV is the version; the file with the latest
version supersedes all similarly named
files with earlier versions and can be
used to validate the archive in its
entirety.
Back to Table of Contents
File Formats
============
All text documents, checksum files, 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, FKs,
and MKs -- are UNIX text files, with a line feed character (ASCII 10)
at the end of the line, and binary kernel 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:
https://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
lessons are available at the NAIF Node of the PDS:
https://naif.jpl.nasa.gov
specifically:
Toolkit: https://naif.jpl.nasa.gov/naif/toolkit.html
Utilities: https://naif.jpl.nasa.gov/naif/utilities.html
Tutorials: https://naif.jpl.nasa.gov/naif/tutorials.html
Lessons: https://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 Hari Nair, Applied Physics Laboratory,
Johns Hopkins University, Laurel, Maryland, and
Marc Costa Sitja, Planetary Data System Navigation and Ancillary
Information Facility Node, Jet Propulsion Laboratory, Pasadena, California.
End of DART SPICE archive description.
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