SoftwareApplication
name: ATHENS
description: ATHENS: Aerodynamic Tracer for High-altitude Environment Numerical Simulations
description: ATHENS is an open-source C++17 ray-tracing code for modelling the aerodynamic behaviour of Resident Space Objects in low Earth orbit under free-molecular, hyperthermal flow conditions. It is intended for orbital-aerodynamics applications where intermolecular gas collisions are negligible on the scale of the spacecraft, making a ray-tracing treatment more efficient than full DSMC or TPMC simulation. The code represents the atmosphere through gas rays travelling through a cuboidal computational domain. These rays are generated from the domain boundaries according to the prescribed free-stream velocity, gas temperature, and molecular species. Each ray carries a molecular mass flux and has a velocity composed of a bulk flow component and a thermal component sampled from a Maxwellian distribution. Spacecraft geometries are imported from STL files and represented as triangular surface meshes. ATHENS detects ray-surface intersections with the geometry, computes the transferred momentum, and generates reflected rays according to the selected gas-surface interaction model. The code supports repeated reflections, making it suitable for both convex and concave geometries. The currently implemented gas-surface interaction models are: DRIA: Diffuse Re-emission with Incomplete AccommodationCLL: Cercignani-Lampis-Lord scattering kernel ATHENS computes global aerodynamic force and moment coefficients, including drag, lift, and side-force components. It can also compute surface-resolved pressure and shear coefficient distributions over the triangular mesh.
code repository: https://data.4tu.nl/v3/datasets/3ba5a514-26b7-4c98-a120-fc16f5dc52dd.git
author: https://orcid.org/0000-0002-1066-8368
keywords: low-earth orbit
keywords: free molecular flow
keywords: gas-surface interaction
keywords: Test Particle Monte Carlo
keywords: Direct Simulation Monte Carlo (DSMC)
programming language: C
programming language: C++
programming language: Markdown
programming language: Other
programming language: Python
programming language: Shell
license:
  creative work: creativeWork
    name: Apache-2.0

https://orcid.org/0000-0002-1066-8368
type: Person
given name: Sabin-Viorel
family name: Anton
name: Sabin-Viorel Anton