The LADEE SPICE Data Archive
========================================================================
Last update: August 25, 2021
Introduction
============
This document describes the LADEE SPICE archive, containing
observation geometry and other ancillary data in the form of SPICE
System kernel files for the LADEE 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
MK Files
Miscellaneous Files
Checksum Files
File Formats
SPICE Software and Documentation
Contact Information
Cognizant Persons
Overview
========
This archive includes the complete set of LADEE, 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 the later phase of the LADEE
launch, 2013-09-07, through the approximate lunar impact end-of-mission,
2014-04-18.
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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 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.
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_ladee_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 and binary 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 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 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, determined by the JPL Solar System Dynamics group and
are named DEXXX, e.g. DE432.
- reconstructed spacecraft trajectory SPKs
These SPKs contain the reconstructed LADEE spacecraft
trajectory for cruise determined by the LADEE Navigation
(NAV) team, GSFC.
- actual impact site position SPKs
These SPKs contain the actual location of the LADEE
end-of-mission impact site in the Moon body-fixed frame,
determined by the LADEE Navigation (NAV) team, GSFC.
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.
- reconstructed spacecraft cruise trajectory SPKs
ladee_r_YYMMDD_YYMMDD_PPP_vVV.bsp
where
YYMMDD are the file coverage start and stop dates
PPP is the mission phase:
pha launch and phasing loop
loa lunar orbit acquisition and commissioning
sci primary and extended science phases
VV is the version; the file with the latest
version supersedes all similarly named files
with earlier versions.
- actual impact site position SPKs
ladee_r_YYMMDD_YYMMDD_imp_vVV.bsp
where
YYMMDD are the file coverage start and stop dates
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, JLP.
- high accuracy lunar orientation binary PCKs
These PCKs contain high accuracy lunar orientation data from the
JPL Solar System Dynamics Group's planetary ephemeris DE421. This
kernel yields the orientation the the lunar principal axes (PA)
reference frame (defined by DE421) relative to the ICRF.
Applications using this file will also need to load a generic
lunar frame kernel also provided in this archive. Produced by
NAIF, JLP.
The PCK files are provided under the spice_kernels/pck
directory and are named according to the following scheme:
- 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.
- high accuracy lunar orientation PCKs
moon_pa_deVVV_YYYY_YYYY.bpc
where
VVV is the ephemeris version
YYYY are the file coverage start and stop years.
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.
The most detailed description of the data in a binary PCK 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
IK Files
IK (Instrument Kernel) files contain instrument parameters relevant
for computing an instrument's observation geometry such
field-of-view definitions, CCD and optical distortion
characteristics, and internal timing parameters.
This archive includes text IK files for LADEE instruments, for
which common instrument geometric parameters normally stored in IKs
are applicable, such as Lunar Dust EXperiment (LDEX), Neutral Mass
Spectometer (NMS), and Ultraviolet and Visible light Spectrometer (UVS).
The IK files are provided under the spice_kernels/ik
directory and are named according to the following scheme:
- instruments IK files
ladee_NAME_vVV.ti
where
NAME is the instrument acronym:
ldex Lunar Dust EXperiment (LDEX)
nms Neutral Mass Spectometer (NMS)
uvs Ultraviolet and Visible light
Spectrometer (UVS)
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 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 reconstructed
spacecraft orientation covering the whole mission.
The CK files are provided under the spice_kernels/ck
directory and are named according to the following scheme:
- reconstructed spacecraft cruise orientation CKs
ladee_YYMMDD_YYMMDD_vVV.bc
where
YYMMDD are the file coverage start and stop dates
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 generic text LSK version 0010 contains leap second data up to
and including the June 30, 2012 leapsecond.
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 nominal and actual
correlation data for the main LADEE on-board clock.
The SCLK files are provided under the spice_kernels/sclk
directory and are named according to the following scheme:
- main LADEE spacecraft clock SCLK files containing actual data
ladee_clkcor_YYMMDD_YYMMDD_vVV.tsc
where
YYMMDD are the file applicability start and stop dates
VV is the version; the file with the latest
version supersedes all similarly named
files with earlier versions.
- main LADEE spacecraft clock SCLK files containing nominal data
ladee_clkcor_YYYYDOY_vVV.tsc
where
YYYYDOY is the product creation time in day of year format
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 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 LADEE spacecraft, its structures, and science instruments.
It also includes text FK files specifying lunar body-fixed reference
frames associated with high-accuracy lunar orientation data and text
FK files to either associate ``Mean Earth'' (ME) or ``Principal Axis''
(PA) frames with the Moon.
The FK files are provided under the spice_kernels/fk
directory and are named according to the following scheme:
- LADEE mission FK files
ladee_vVV.tf
where
VV is the version; the file with the latest
version supersedes all similarly named
files with earlier versions.
- Lunar reference frame specification FK files
moon_YYMMDD.tf
where
YYMMDD is the original release date of the file.
- Lunar reference frame association FK files
moon_assoc_FF.tf
where
FF is the frame to associate with the Moon:
me Mean Earth
pa Principal Axis.
The most detailed description of the data 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
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:
- LADEE whole mission MK files
ladee_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
these meta-kernels:
- the latest archived versions of LSK, PCK, and each kind of
SCLKs, IKs, FKs, SPKs, and CKs were included
- the lunar reference frame is associated with the 'Principal Axes'
frame.
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:
- LADEE 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 PCKs --
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: https://naif.jpl.nasa.gov
Back to Table of Contents
Cognizant Persons
=================
This archive was produced by Marc Costa Sitja and Boris Semenov,
Planetary Data System Navigation and Ancillary Information
Facility Node, Jet Propulsion Laboratory, Pasadena, California.
End of LADEE SPICE archive description.
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