listed in approximately chronological order based on when they first appeared

3D Surface Energy Balance Models

These models include direct solar irradiance, subsurface heat storage, terrain shadowing, and terrain irradiance.

• Diviner thermal model, Paige et al. (2010), suppl.
  random rays that sample terrain irradiance
• Rozitis & Green (2011)
• Schörghofer
  multigrid accelerated horizons, viewfactor-based terrain irradiance
  https://github.com/nschorgh/Planetary-Code-Collection
• Rubanenko
  https://github.com/liorruba/thermal_mode
• Gläser & Gläser (2019)
• Oxford3D, King et al. (2020)
  https://github.com/tw7044/O3DTM
• NIMBUS, Davidsson (JPL) ~2021
• PRATHAM-Moon, Durga Prasad et al. (2022), Ambily et al. (2026)
  uses COMSOL
• python-flux Potter et al. (2023)
  Fast terrain irradiance method based on hierarchic compression of viewfactor matrix; links to Embree or CGAL
  https://github.com/sampotter/fluxpy
  Faster re-implementation using new butterfly library by Bertone
  https://github.com/steo85it/butterflux
• Yin et al. (2024)
• Formisano et al. (2024)
  COMSOL-based
• MoCSI, Schukart et al. (2026)
  https://gitlab.git.nrw/uni-ms/ag-gundlach/public/mocsi
• TEMPEST: A Modular Thermophysical Model for Airless Bodies with Support for Surface Roughness and Non-Periodic Heating
  https://github.com/duncanLyster/TEMPEST/
• PTM3D Hayne et al.
  links to Embree, uses GPUs
• Rubanenko; Claude-Code-drafted model
  OptiX ray-tracing engine, uses GPUs

(Note: Most of these models are limited to small domains <~50,000 facets, because the numerical methods they use do not scale well.)

Dedicated Terrain Shadowing Models

• IllumNG Mazarico et al. (2011), Mazarico et al. (2018)
  terrain shadowing and direct irradiance for very large domains (~10⁹ facets)
• O’Brien & Byrne (2022) finds doubly-shadowed regions
  https://github.com/pcobrien/DoubleShadows/
• Tong et al. (2023)
  terrain shadowing with LOLA data

Scattered Illumination (incomplete list)

• Mahanti et al. (2022)
  short-wavelength secondary illumination (for ShadowCam)
• shadepy
  https://github.com/steo85it/shapespy
• Qian et al. (2025)
  shape-from-shading in shadowed regions

1D Thermal Models with Radiative Cooling

• KRC - Mars Kieffer (1977), Kieffer (2013)
  still widely used in Mars community, explicit time step
  https://krc.mars.asu.edu
• Spencer (1989)
  still widely used in asteroid community, explicit time step
  https://www2.boulder.swri.edu/~spencer/thermprojrs/
• Schorghofer & Khatiwala (2024) - dates back to 2001
  semi-implicit solver
  https://github.com/nschorgh/MSIM (Mars)
  https://github.com/nschorgh/Planetary-Code-Collection (airless bodies)
• MARSTHERM Clifford et al. (1986), Putzig et al. (2013)
  explicit time step
  https://marstherm.psi.edu
• heat1d Hayne et al. (2017)
  includes iterative and semi-implicit solvers
  https://github.com/phayne/heat1d
• MultIHeatTS Mergney & Schmidt (2024)
  fully implicit solver
  https://gitlab.dsi.universite-paris-saclay.fr/cyril.mergny/multiheats

(Note: There are many more 1d model implementations.)

compiled by Norbert Schörghofer in 2026. For additions or corrections email me.