The STEP-TAS / TASverter ecosystem

This document provides access to more detailed help information about TASverter and the TASverterGUI, as well as a high level overview of the protocol, tools, and the most common conversion workflows.

What is STEP-TAS?

STEP-TAS is a data exchange protocol

  • It uses the building blocks provided by the ISO-10303 standards, i.e. “STEP”

  • It was designed specifically for Thermal Applications for Space, i.e. “TAS”

  • It is completely different to those protocols used for CAD model exchange.

The STEP-TAS protocol consists of four modules of functionality:

  • STEP-NRF: network model and results format for flight, test and simulation data

  • STEP-MGM: meshed geometric model using simple thin-shell primitives

  • STEP-SKM: space kinematic model for articulated joints (currently unused)

  • STEP-SMA: space mission aspects for orbits and pointing (currently unused)

The STEP-TAS protocol is an ECSS standard available for free download at:

What is TASverter?

TASverter is an in-house tool written by ESA as a STEP-TAS test bench and validator.


  • It provides strict STEP-TAS file validation and a STEP-TAS geometry viewer

  • It now provides a TMMverter module for converting some thermal network model formats

  • A graphical user interface is available to help the user set conversion options


Which tools currently work with STEP-TAS?

The diagram below shows the possible workflows for common model conversions:

  • the black lines show the currently recommended paths for geometry conversion

  • the grey lines show older-but-still-usable-with-extra-work paths for older geometry formats

  • the blue lines show the thermal network model conversion paths

Note that there is no direct conversion path from a geometry to a thermal network model.

Model conversion workflows

Note that conversions of ESATAN-TMS erg, THERMICA-4 sysmsh and Thermal Desktop dwg files are not handled by TASverter, but by external tools (see links).

TASverter is still useful for STEP-TAS file validation, the STEP-TAS geometry file viewer, and its TMMverter module for converting ESATAN and SINDA/Fluint TMM files. Note that TASverter handles geometry to geometry, or network model to network model conversion, but not both.