Thermica and thermisol

Overview

Thermica is a thermal analysis tool that converts geometric models into mathematical representations to perform detailed simulations of space systems. It handles thermal modelling for spacecraft on planetary or interplanetary missions, computing factors like radiative and conductive couplings, solar and planetary fluxes, and thermal exchanges. 
Thermica integrates advanced algorithms, including ray-tracing for radiative exchange factors, and supports detailed optical property management.

Thermisol, the solver paired with thermica, processes temperature calculations based on the detailed nodal descriptions and thermal inputs from thermica, enabling precise temperature predictions for complex space missions.

Thermica main functions

Main functions of thermica

Thermica

The main functions of Thermica are as follows:

  • Geometry modelling and physical properties & meshing
  • Mission modelling: orbit & pointing
  • Physical simulation: radiative & conductive couplings, solar & planetary fluxes, convection
  • Translation of the geometrical problem to a nodal network problem

These functions support thermal analysis at different stages of the spacecraft design and analysis process, contributing to the broader engineering workflow within Systema.

Raytracing thermica

Radiative Exchange Simulation in Thermica

Thermica

Thermica features a module for calculating radiative exchange factors using a multi-threaded ray-tracing algorithm. It evaluates various geometric and radiative factors to accurately simulate thermo-optical properties in UV and IR spectra.

This application enables to handle absorptivity, emissivity, and the reflective and transmissive characteristics of materials. Thermica also allows for property adjustments based on the angle of incidence and defines wavelength-dependent characteristics, supporting detailed thermal visualisation.

Solar and Planetary Flux Calculations

Thermica

Thermica accurately computes solar and planetary flux contributions to the thermal budget. Solar fluxes are determined based on the Sun's position using a ray-tracing algorithm and thermo-optical properties. The Sun can be modelled as either at infinite or finite distance.

Planetary fluxes, including IR emissions and UV albedo, are derived from radiative exchange factors, with IR modelled as black body emission (uniform or non-uniform) and albedo defined by a variable coefficient. These calculations feed into the broader simulation chain for realistic spacecraft modelling.

 

Thermica Solar and Planetary Flux Calculations
Thermica conduction mirror

Conduction Effects Modelling in Thermica

Thermica

Thermica models conduction effects using two methods.

The simplified RCN method is a first-order approach that removes edges and simplifies node-to-node couplings for standard scenarios.

The RCN method, a second-order approach, uses a quadratic temperature profile within each node and integrates Fourier's law on edges to calculate conductive fluxes. This method, compatible with the finite volume approach, creates a new data structure for thermal nodes and edge interactions, enhancing thermal simulation precision.

Thermisol – A Powerful Temperature Solver

Thermisol

Thermisol computes temperature solutions automatically based on Thermica’s outputs: a nodal description, complementary items, couplings, and fluxes. These elements form a detailed thermal model.

Thermal models can be easily enriched thanks to a very accessible thermal modelling language (Mortran) and a powerful user library. This enables a fast, robust, and smart temperature solver offering both steady-state and transient analysis. Thermisol plays a key role in the engineering workflow and supports the accuracy required for high-fidelity simulation results.

 

thermica_thermisol

Discover more about applications

APPLICATIONS