Data Sources and Licenses¶

Huira’s code is released under the MIT License. The data that Huira’s examples use is not part of Huira. Some of it is hosted at media.huira.space: 3D models, textures and star catalogs. The rest comes straight from its provider, such as SPICE kernels from NASA’s NAIF. Each dataset has its own license, listed on this page, and each example’s README lists the files it uses.

Please credit the data’s providers when you publish work made with it, including rendered images.

The Tycho-2 star catalog is licensed for non-commercial use only. Huira’s MIT license does not change that. If you render stars for commercial work, check that your use is allowed: see Tycho-2 star catalog.

Data	Where to get it	License
Tycho-2 star catalog	media.huira.space/data/stars/tycho2/	CC BY-NC 3.0 IGO (non-commercial)
SPICE kernels	NASA’s NAIF	Redistributable unmodified
NASA spacecraft models	media.huira.space/data/models/nasa/	No copyright; NASA’s media guidelines
Solar System textures	media.huira.space/data/textures/solar_system/	CC BY 4.0
Kernels that ship with Huira	Included with Huira	Redistributable unmodified

Each folder on media.huira.space holds an ATTRIBUTIONS.txt, with its data’s source, license and how to credit it, and a SHA256SUMS, to check downloads with sha256sum -c SHA256SUMS.

Tycho-2 star catalog¶

The Tycho-2 Catalogue of the 2.5 million brightest stars, from ESA’s Hipparcos mission, as distributed by CDS, Strasbourg (VizieR catalog I/259).

SPICE kernels¶

SPICE kernels hold ephemerides, orientations, frames and clocks. Huira does not host them: they come straight from NASA’s Navigation and Ancillary Information Facility (NAIF), which keeps them at permanent addresses. The examples that use SPICE list the kernels they load, with links.

Get them: NAIF’s generic kernels (planetary and satellite ephemerides, planetary constants, the Earth’s orientation), and missions’ kernels in NAIF’s Planetary Data System archives.
License: NAIF permits redistributing the kernels it distributes, as long as they are not modified (NAIF’s rules).
Credit: NAIF asks that SPICE, NAIF, and the teams that produced the data be acknowledged (how to cite). A kernel’s comments name its producer, and often the papers to cite; JPL’s planetary ephemeris DE440, for example, is Park, R. S., et al. 2021, “The JPL Planetary and Lunar Ephemerides DE440 and DE441”, The Astronomical Journal, 161, 105. For SPICE and NAIF:
- Acton, C. H. 1996, “Ancillary Data Services of NASA’s Navigation and Ancillary Information Facility”, Planetary and Space Science, 44(1), 65-70, doi:10.1016/0032-0633(95)00107-7
- Acton, C., Bachman, N., Semenov, B., and Wright, E., “A look toward the future in the handling of space science mission geometry”, Planetary and Space Science, doi:10.1016/j.pss.2017.02.013
- A mission’s archive is cited by its DOI, which the PDS Engineering Node’s DOI search finds from the archive’s identifier (for example, urn:nasa:pds:orex.spice for OSIRIS-REx).

NASA spacecraft models¶

NASA’s 3D models of spacecraft: the Gateway core module and OSIRIS-REx. The folder’s ATTRIBUTIONS.txt gives each model’s source page and original file name.

Get them: media.huira.space/data/models/nasa/
- gateway.glb: the Gateway core module, from NASA’s 3D Resources, published there as Gateway Core.glb.
- orex.glb: the OSIRIS-REx spacecraft, from NASA Science, published there as Osiris_Rex.glb, credited to NASA’s Visualization Technology Applications and Development group (VTAD).
Huira’s copies are renamed, and otherwise unchanged.
License: NASA’s media are generally not copyrighted and may be used without permission. NASA’s media usage guidelines apply: credit NASA, do not use the models to imply that NASA endorses anything, and do not use NASA’s insignia.
Credit: “Gateway model: NASA.” and “OSIRIS-REx model: NASA/VTAD.” Or, for several models at once, “Spacecraft models: NASA.”

Solar System textures¶

Textures of the Earth and the planets, from Solar System Scope: Mercury, Venus (surface and atmosphere), Mars, Jupiter, Saturn and its rings, Uranus and Neptune, and for the Earth its surface by day and by night, its clouds, a normal map, a roughness map and a city emission map.

Get them: media.huira.space/data/textures/solar_system/
Source: Solar System Scope, based on NASA elevation and imagery data, with colors tuned to true-color photographs from Messenger, Viking, Cassini and the Hubble Space Telescope. Solar System Scope notes that unmapped regions are filled with fictional terrain, and that colors are slightly more saturated than true color. Uranus and Neptune are only published at 2k; the rest are 8k (Venus’s atmosphere, 4k).
Modifications: Two Earth maps were made for Huira by Christopher Gnam:
- The roughness map (8k_earth_roughness_map.tif), by modifying the specular map.
- The city emission map (8k_earth_city_emission.jpg), by modifying the night map.
License: CC BY 4.0. The roughness and city emission maps, adaptations, are distributed under the same license.
Credit: “Textures: Solar System Scope (solarsystemscope.com), CC BY 4.0.” For the Earth, add “Roughness map adapted from its specular map; city emission map adapted from its night map.” Images rendered with the textures should carry this credit too.

Kernels that ship with Huira¶

Huira includes two of NAIF’s generic kernels, in its data/kernels/ folder:

lsk/naif0012.tls: leap seconds, which Huira loads when it first converts a time.
pck/pck00011.tpc: planetary constants (sizes and orientations), which huira.spice.load_default_pck() loads.

Both are unmodified, and redistributed under NAIF’s rules.

Leap seconds are to be discontinued by 2035 (CGPM resolution, 2022), so naif0012.tls is unlikely to change often, if ever. It stays included either way: SPICE’s time system needs a leap-seconds kernel to run.