The Venus Climate Orbiter Akatsuki SPICE Data Archive
=======================================================================
Last update: March 23, 2022
Introduction
============
This document describes the Venus Climate Orbiter (VCO, also
known as PLANET-C and AKATSUKI) SPICE archive, containing
observation geometry and other ancillary data in the form of SPICE
System kernel files for the Venus Climate Orbiter Akatsuki 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
MK Files
Miscellaneous Files
Checksum Files
Orbit Number Files
File Formats
SPICE Software and Documentation
Contact Information
Cognizant Persons
Overview
========
This archive includes the complete set of VCO 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 VCO launch, 2010-05-20,
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.
This archive supersedes the Venus Climate Orbiter PDS3 data set:
Murakami, S., Y. Yamamoto, K. McGouldrick, G. L. Hashimoto,
N. Hirata, VENUS CLIMATE ORBITER SPICE KERNELS V1.0,
VCO-V-SPICE-6-V1.0, NASA Planetary Data System, 2017.
https://doi.org/10.17597/isas.darts/vco-00001
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. Some of The SPICE kernels present in the first release of this bundle
have embedded PDS3 labels. This is intentional in order to preserve
the original kernels from the PDS3 data set that this PDS4 bundle
supersedes.
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_vco_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.
| |
| |-[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.
| |
| +-[orbnum] Directory containing orbit number files.
| |
| |-- *.orb Text orbit number files.
| +-- *.xml PDS4 labels for orbit number 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, detector 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 are located under the spice_kernels/fk
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.
Back to Table of Contents
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 under the spice_kernels/spk
directory (Only the leading portions of the file names are shown; the file
name extensions of the binary SPK files are always ``.bsp''):
vco_YYYY_vVV SPK files containing the trajectory of the
Venus Climate Orbiter Akatsuki spacecraft relative
to the Sun or Venus barycenter, mostly
created during operations by the ISAS orbit
determination group, JAXA. Most of source
data for 2010 and for some periods around
orbital maneuvers in 2015 were created by
the NASA JPL Navigation Team. YYYY in the
file name that represents the year identify
the period covered by the file.
vco_de423_de430 vco_de423_de430 combined planetary ephemeris
SPK containing data from both de423 and
de430. This kernel contains the results of
merging portions of DE423 with DE430, to
produce a single SPK file that should be
valid for the bulk of the entire Venus
Climate Orbiter Akatsuki mission.
If this data set contains multiple SPK files for a particular period,
the one with the latest version (VV) supersedes all previous 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 (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.
The PCK files are provided under the spice_kernels/pck
directory (Only file names are shown; the file name extensions of the text
PCK kernel files are always ``.tpc''):
vco_gm_de431_vVV PCK file containing mass parameters used in
the Venus Climate Orbiter Akatsuki mission. This
file is based on gm_de431.tpc, created by NAIF,
and then modified only GM values for Venus and
Venus barycenter, where VV is the version number.
pck00010 generic PCK file containing IAU 2009 rotation
and shape constants for planets, satellites, and
some asteroids, created by NAIF.
If this data set contains multiple PCK files, the one with the latest
version (VV) supersedes all previous versions.
In most cases these two PCK files
pck00010.tpc
vco_gm_de431_vVV.tpc
should be loaded into a user's application to process data for
the science phase(s) of the mission.
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 (Instrument Kernel) files contain instrument parameters relevant
for computing an instrument's observation geometry such field-of-view
definitions, detector and optical distortion characteristics, and internal
timing parameters.
The following IK files are provided under the spice_kernels/ik
directory (only the leading portion of the file name is shown; the extension
of all file names is ``.ti''):
vco_ir1_vVV IK file containing FOV and reference frame
definitions for the VCO 1-MICRON camera (IR1)
instrument, created by the PLANET-C IR1 Team.
vco_ir2_vVV IK file containing FOV and reference frame
definitions for the VCO 2-MICRON camera (IR2)
instrument, created by the PLANET-C IR2 Team.
vco_lac_vVV IK file containing FOV and reference frame
definitions for the VCO Lightning and Airglow
Camera (LAC) instrument, created by the
PLANET-C LAC Team.
vco_lir_vVV IK file containing FOV and reference frame
definitions for the VCO Longwave Infrared
Camera (LIR) instrument, created by the
PLANET-C LIR Team.
vco_uvi_vVV IK file containing FOV and reference frame
definitions for the VCO Ultra Violet Imager
(UVI) instrument, created by the PLANET-C UVI
Team.
If this data set contains multiple IK files for a particular instrument,
the one with the latest version (VV) supersedes all previous versions.
In most cases these IK files
vco_ir1_vVV.ti
vco_ir2_vVV.ti
vco_lac_vVV.ti
vco_lir_vVV.ti
vco_uvi_vVV.ti
should be loaded into a user's application to process data for
the science phase(s) of the mission.
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 under th spice_kernels/ck
directory and are named according to the following scheme:
The following CK files are provided in the spice_kernels/ck
directory (only the leading portion of the file name is shown; the extension
of all CK file names is ``.bc''):
vco_YYYY_vVV CK files containing reconstructed Venus
Climate Orbiter Akatsuki spacecraft orientation,
created during operations by the PLANET-C
Project Team. YYYY in the file name that
represents the year identify the period
covered by the file and VV is the version
number.
vco_YYYY_pred_vVV CK files containing predicted orientation
of the Venus Climate Orbiter Akatsuki spacecraft,
covering only ``gaps'', i.e., periods
without data in the yearly reconstructed CK
files, vco_YYYY_vVV, created by the
PLANET-C Project Team. YYYY in the file
name that represents the year identify the
period covered by the file and VV is the
version number. For the case of YYYY with
2012 and 2013, there aren't any gaps in the
reconstructed CKs, so the predicted CKs for
2012 and 2013 don't exist.
vco_sap_nominal_vVV CK files containing two Solar Array
Paddles' orientation of the Venus Climate
Orbiter Akatsuki spacecraft, with respect to the
dynamic frame named ``VCO_SAP_NOMINAL''.
VV in the file name is the version number.
vco_sap_YYYY_vVV CK files containing two Solar Array
Paddles' orientation of the Venus Climate
Orbiter Akatsuki spacecraft, with respect to the
Venus Climate Orbiter Akatsuki spacecraft body-fixed
frame, created by the PLANET-C Project
Team. YYYY in the file name that represents
the year identify the period covered by the
file and VV is the version number.
vco_xmga_YYYY_vVV CK files containing two X-band Medium Gain
Antennas' orientation of the Venus Climate
Orbiter Akatsuki spacecraft, with respect to the
Venus Climate Orbiter Akatsuki spacecraft body-fixed
frame, created by the PLANET-C Project
Team. YYYY in the file name that represents
the year identify the period covered by the
file and VV is the version number.
If this data set contains multiple CK files for a particular period,
the one with the latest version (VV) supersedes all previous versions.
In most cases these CK files
vco_YYYY_pred_vVV.bc
vco_YYYY_vVV.bc
vco_sap_nominal_vVV.bc
vco_sap_YYYY_vVV.bc
vco_xmga_YYYY_vVV.bc
should be loaded in this order into a user's application to process
data for the mission.
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 following LSK file is provided under the spice_kernels/lsk
directory:
naifVVVV.tls
where VVVV is the file version. The latest LSK file supersedes all
previous 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).
The following Frames Kernel files are provided under the spice_kernels/sclk
directory (only the leading portion of the file name is shown; the extension
of all file names is ``.tsc''):
vco_vVV SCLK file containing clock correlation data for the
Venus Climate Orbiter Akatsuki spacecraft on-board clock,
created by the PLANET-C Project Team, where VV is the
version number.
If this data set contains multiple SCLK files for a particular period,
the one with the latest version (VV) supersedes all previous 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.
The following Frames Kernel files are provided under the spice_kernels/fk
directory (only the name portion of the file name is shown on the right;
the extension of all file names is ``.tf''):
rssd0002 Generic Frames Definition Kernel for ESA
Planetary Missions. 0002 is the version number.
This file is used in the Venus Climate Orbiter
Akatsuki mission to calculate orbit number for the Venus
Climate Orbiter Akatsuki spacecraft.
vco_spacecraft_vVV FK file containing the definition of the Venus
Climate Orbiter Akatsuki spacecraft body-fixed frame
and frames for its engineering structures and
science instruments, created by the PLANET-C
Project Team, where VV is the version number.
If this data set contains multiple FK files, the one with the latest
version (VV) supersedes all previous versions.
In most cases both FK files should be loaded into a user's
application to process data for the science phase(s) of the mission.
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
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.
The text MK files are provided under the spice_kernels/mk
directory follow this pattern:
vco_pds4_vVV.tm
where ``VV'' is the file version and ``pds4'' indicates that the text
and PATH_VALUE key in meta-kernel versions 01 to 05 differ from the
meta-kernels present in the superseded PDS3 data set.
Multiple versions of a meta-kernel may exist if new kernels were
added to the archive in a later release and the meta-kernel for
that it 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 is present, then the
file with the latest version number supersedes all earlier
versions.
(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
these meta-kernels:
- the latest archived versions of LSK and FK were included
- the sets of the CKs, SPKs, PCKs, IKs, and SCLKs were picked
according to the recommendations made in the corresponding
sections of this document
- the predicted CKs where produced for Venus Climate Orbiter Akatsuki
spacecraft attitude are also included in the metakernel, listed
before each reconstructed CK kernel for the spacecraft attitude.
This way, the reconstructed information will have preference,
and the predicted attitude will be used only for periods of time
when there is no reconstructed attitude
- the nominal CK where produced for solar array paddles
of Venus Climate Orbiter Akatsuki spacecraft is also included in the
metakernel, listed before each reconstructed CK kernel for the
solar array paddles orientations. This way, the reconstructed
information will have preference, and the nominal orientation
will be used only for periods of time when there is no
reconstructed orientation
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 and orbit number 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:
checksum_vVVV.tab
where ``VVV'' is the file version.
The file with the latest version supersedes all files with earlier versions
and can be used to validate the archive in its entirety.
Back to Table of Contents
Orbit Number Files
An orbit number (ORBNUM) file provides a table of records ordered
by an increasing orbit numbering scheme. The orbit number changes
at every periapsis event and the information contained for each
record includes:
- Orbit number ("No".)
- Periapsis UTC time ("Event UTC PERI")
- SCLK time ("Event SCLK PERI" )
- Apoapsis UTC time ("OP-Event UTC APO")
- Sub-solar geodetic longitude and latitude (SolLon, SolLat), in
the IAU_VENUS reference frame.
- Sub-spacecraft geodetic longitude and latitude (SC Lon, SC Lat),
in the IAU_VENUS reference frame.
- Altitude of the vehicle above the primary body (Alt)
- Inclination of the vehicle orbit (Inc)
- Eccentricity of the orbit plane about the primary body (Ecc)
- Longitude of the ascending node of the orbit (LonNode)
- Argument of periapsis of the orbit (Arg Per)
- Solar distance the time of the orbit event (Sol Dist)
- Semimajor axis of the orbit (Semi Axis)
All the orbital elements are calculated in the VME2000 reference
frame. See rssd0002.tf for details about this frame.
The ORBNUM files have been generated during the mission using the
NAIF's ORBNUM utility program for consolidated spacecraft trajectory
SPK files for the orbital phases of the mission. Orbit number 1
corresponds to the first orbit, started from 2015-12-07.
The ORBNUM files are provided under the miscellaneous/orbnum
directory and are named:
vco_vVV.orb
where ``VV'' is the file version.
The file with the latest version supersedes all files with earlier versions.
The files included in this dataset are the most recent files
available at the moment of the compilation of each release of this
dataset, which should span at least the same time interval as all
the SPK files included in the dataset.
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, FKs,
and MKs --, the ORBNUM files, and the checksum files are UNIX text files,
with a line feed character (ASCII 10) at the end of each line. Binary
kernel files -- SPKs and CKs -- 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
===============================
Institute of Space and Astronautical Science (ISAS),
Japan Aerospace Exploration Agency (JAXA)
3-1-1 Yoshinodai, Chuo-ku, Sagamihara-shi,
Kanagawa 252-5210, Japan
WWW Site: https://darts.isas.jaxa.jp/about.html.en
Electronic mail address: darts-admin@ml.isas.jaxa.jp
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: https://naif.jpl.nasa.gov
Back to Table of Contents
Cognizant Persons
=================
This archive was designed and produced by Shin-ya Murakami,
Yukio Yamamoto, and Kevin McGouldrick.
End of Venus Climate Orbiter Akatsuki SPICE archive description.
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