Scientific numerical data and model attribution

This notice records the engineering basis and provenance of the specific
numeric tables below. It does not claim an Apache-2.0 or public-domain
license for all externally sourced scientific data. A mathematical model,
its numerical constants, and its computed output are distinct from the
copyrighted source code or explanatory prose used to implement or describe it.
No IERS implementation code or book prose is distributed in these tables.

Earth orientation: data/planetary_coeff/eopc04_08.62-now
  Preserve the provider attribution and permission record in IERS-EOP.txt.
  That file documents Christian Bizouard's 9 April 2017 permission for
  unlimited copying and use of EOP files with reference attribution, as
  archived at the exact public source URL:
    https://lists.iana.org/hyperkitty/list/tz%40iana.org/message/DSTTJE5RC3PSYHPBVNR7J3FFDZMFH4TW/
  The retained NASA/GMAT snapshot's numeric bytes are unchanged; its
  late-2026 forecast rows are not relabeled as current final observations.

The U.S. Copyright Office's primary guidance distinguishes procedures,
methods, systems, and their underlying principles from the copyrightable
expression describing them:
  https://www.copyright.gov/circs/circ33.pdf
  https://www.copyright.gov/title17/92chap1.html (Sections 102(b) and 105)

Time: data/time/tai-utc.dat
  The file is byte-identical to the U.S. Naval Observatory's authoritative
  TAI-minus-UTC historical standard values retrieved on 2026-10-01:
    https://maia.usno.navy.mil/ser7/tai-utc.dat
  USNO is the U.S. Government service providing these time-standard data.
  The file's numerical standard offsets/drifts are recorded as scientific
  time-standard facts and official Government data; they are not relabeled
  as Apache-2.0 source code. No book prose, illustrations, or unrelated
  third-party compilation is copied. Attribution: U.S. Naval Observatory.
  The table includes pre-1972 UTC drift segments and post-1972 leap seconds;
  its latest effective change is 2017-01-01. No updates are downloaded.

Nutation: data/planetary_coeff/NUTATION.DAT
  This is a new numeric-only presentation of the two models implemented
  by GMAT's coordinate transformations: 1980 (106 terms) and 1996 (263
  terms). The unused 1950 and unsupported 2000 sections are not included.
  All argument multipliers and numerical coefficients of both implemented
  models are unchanged. The implemented records retain the exact NASA
  baseline order, including ties, because native summation follows record
  order. Only numeric formatting and independently written headings differ.
  python/tools/generate_coordinate_data.py verifies the source coefficient
  multisets and the hash-pinned NASA order before writing those records.

  The 1980 values match ERFA 2.0.1 nut80.c exactly. Preserve the BSD-3-Clause
  notice in ERFA.txt for this component. ERFA is derived with permission
  from SOFA; this is an ERFA-derived table, not an official SOFA release.
    https://github.com/liberfa/erfa/releases/tag/v2.0.1
    https://raw.githubusercontent.com/liberfa/erfa/9915ba38c9365f8b0738269b8c2ac1fdd5f8dee3/src/nut80.c

  The 1996 values match all 263 luni-solar coefficient records in the
  official IERS Conventions (1996) KSV_1996_3 numerical model listing.
  Only its numerical argument multipliers and coefficient values are
  transcribed. Neither the Fortran algorithm nor explanatory prose is
  included. These functional mathematical model coefficients are the
  scientific-data basis; this is not a claim that all IERS software is
  freely relicensable. Attribution: IERS Conventions (1996), D. D. McCarthy
  (ed.), IERS Technical Note 21, KSV_1996_3 model.
    https://iers-conventions.obspm.fr/conventions_archive.php
    https://iers-conventions.obspm.fr/archive/1996/1996IERSConventionsArchive.tar.gz

ICRF: data/icrf/ICRF_Table.txt
  Exact numeric bytes and original unequal sampling grid restored from
  NASA GMAT commit 9363e129be366520c6edb0b4079204ed60666007. The table has
  49,063 numeric-only rotation-vector rows, A1MJD 6935.000000397937 through
  58070.00000039794, with gaps up to 16 days. Its original historical
  generator and provider-specific grant remain unidentified. Copying the
  hash-pinned NASA file preserves its values; it does not regenerate or
  independently validate the original physical model.
    https://raw.githubusercontent.com/nasa/GMAT/9363e129be366520c6edb0b4079204ed60666007/application/data/icrf/ICRF_Table.txt

  Reuse is recorded on a narrow U.S. scientific-numerical-data assessment,
  distinguishing numeric facts/methods from authored expression. No authored
  prose or table artwork is present in this file. This is not a verified
  provider license, blanket Government/public-domain designation, or finding
  about all compilation, contractual or non-U.S. rights. Preserve NASA/GMAT
  attribution and the explicit unknown-generator limitation.
    https://www.copyright.gov/help/faq/faq-protect.html
    https://www.copyright.gov/title17/92chap1.html (Sections 102 and 103)

  The previous ERFA-derived 51,136-row daily alternative changed both values
  and grid. Its saved validation is historical evidence about that excluded
  alternative, not the default table. The offline generator retains an
  explicit --erfa-icrf-output option for research; it is neither installed
  nor used implicitly. Preserve ERFA.txt for any ERFA-derived output and
  identify it as GMAT Py output, not an official ERFA/SOFA release.

Earth orientation PCK: data/planetary_coeff/earth_latest_high_prec.bpc
  Exact NASA-baseline bytes restored, including embedded NAIF metadata.
  This is the NAIF-created 2026-03-16 snapshot, identified in its comments
  as earth_000101_260612_260316.bpc. It covers ET -43135.816087188054 through
  834494469.184639 (2000-01-01 through 2026-06-12), with last input datum
  2026-03-16; later coverage includes prediction. The runtime alias does not
  mean it is the latest snapshot. No automatic refresh is performed.
    https://raw.githubusercontent.com/nasa/GMAT/9363e129be366520c6edb0b4079204ed60666007/application/data/planetary_coeff/earth_latest_high_prec.bpc
    https://naif.jpl.nasa.gov/pub/naif/generic_kernels/pck/earth_000101_260612_260316.bpc
    https://naif.jpl.nasa.gov/naif/rules.html
  NASA Git-blob identity and embedded NAIF producer metadata are verified.
  No fresh direct NAIF-download byte comparison was performed for this
  restored snapshot. The documented reuse basis combines that lineage,
  NAIF's unchanged-kernel rules and the numeric-data assessment above;
  it is not labeled a newly verified provider license. Keep embedded
  comments and NAIF-CSPICE.txt. September 2026 PCK validation saved earlier
  describes the replaced snapshot, not this restored June coverage.

Atmosphere: data/atmosphere/earth/EarthExponentialAtmosphereData.txt
  Regenerated from the 28 refHeight/refDensity/scaleHeight constants in
  NASA GMAT's Apache-2.0 ExponentialAtmosphere.cpp. All 84 numeric values
  are unchanged, including GMAT's documented 350 km density correction.
  Preserve GMAT.txt and the NASA/source attribution in NOTICE.txt.
  Scientific attribution: the exponential model and standard atmospheric
  constants discussed by Vallado and Wertz; no book prose or table artwork
  is copied into this generated CSV. The U.S. Standard Atmosphere (1976)
  is a related Government scientific reference, explicitly identified by
  NASA NTRS as Government work with public use permitted. It is not asserted
  to be a byte-identical source for every value in this particular table.
    https://raw.githubusercontent.com/nasa/GMAT/9363e129be366520c6edb0b4079204ed60666007/src/base/solarsys/ExponentialAtmosphere.cpp
    https://ntrs.nasa.gov/citations/19770009539

Consult DATA_MANIFEST.json for exact identities, generator inputs, and
scientific validation. No scientific-accuracy or legal guarantee is made.
