ArtemisThermalBase

Illumination and regolith temperature for lunar polar terrain, on a laptop.

ArtemisThermalBase traces sunlight across a digital elevation model of the lunar poles and follows the heat into a regolith column under every facet. It answers the questions a landing site or a rover traverse raises: which ground is lit and for how long, how hot and how cold it gets, how long the longest night lasts, and where water ice would survive.

The image above is one lunar day over a 40 km window around Shackleton: 79 202 facets of LOLA topography, the Sun from NAIF DE440, a 16-ray solar disk for penumbra, after one lunar day of spin-up. It took 9 minutes on an eight-core laptop.

Documentation: https://spaceengineerss.github.io/ArtemisThermalBase/ · Getting started · Physics · Configuration · Changelog

Install and run

git clone https://github.com/SpaceEngineerSS/ArtemisThermalBase.git
cd ArtemisThermalBase
python -m pip install -e ".[dem,ephemeris,gui]"

artemis run --duration 24     # synthetic Shackleton-sized bowl, about half a minute
artemis ui output             # look at it in the desktop app

Real terrain takes two downloads from the official sources, both checked:

python tools/fetch_research_data.py --group ephemeris
python tools/prepare_lola_dem.py --extent-km 40 --resolution-m 200 \
    --output data/processed/shackleton_lola_200m.tif
artemis run --config shackleton_preview \
    --dem data/processed/shackleton_lola_200m.tif --output output/shackleton

Python 3.11 or newer. Tested on Windows and Linux; macOS should work but is not in CI.

What is inside

• Shadows from rays to many points of the solar disk, so penumbra and the grazing polar Sun come out right; a compiled BVH builds 583 000 triangles in about a second.
• The Sun from NAIF SPICE (research), Skyfield (preview) or an analytical polar model (offline), all rotated onto the terrain through one tested frame transformation.
• Terrain lowered onto the lunar sphere; optional one-bounce infrared between facets; Hapke albedo; roughness-adjusted emissivity.
• A 6 m regolith column per facet with temperature- and depth-dependent properties (Hayne et al. 2017), all columns advanced in one parallel call.
• Ice stability from Hertz–Knudsen sublimation, classified by the hottest temperature each place reaches.
• A research mode that refuses to run without a provenance-checked DEM, SPICE geometry and enough spin-up.
• A desktop app to set up runs, watch them, inspect a site and compare runs.

Status

The geometry, ray tracing, conduction and data pipeline are tested on every change, and the Sun direction agrees with SPICE. A quantitative comparison with LRO Diviner temperatures has not been done yet; see Validation and limitations before you use a number from here in a publication.

Version 0.5.0 changes results relative to 0.4: the Sun direction was wrong for real ephemerides. Details in the changelog.

Development

python -m pip install -e ".[dev]"
python -m pytest
python -m ruff check .
python -m mypy -p artemis_thermal
python tools/build_docs.py --serve   # the documentation site on localhost:8000

How to contribute is in CONTRIBUTING.md.

Citing

If this software helps your work, cite it with CITATION.cff and cite the data and models it uses (LOLA, NAIF DE440, Hayne et al. 2017), listed in Data.

MIT licence. Mehmet Gümüş, 2026.