Solver Verification
& Validation

What Exists Today

The current platform has real solver verification, a meaningful SAE parity argument, one documented heritage reproduction chain, and working structural temperature handoff infrastructure. It does not yet have a published open benchmark pack against Thermal Desktop or ESATAN, and it does not yet have a completed public commercial FEA pilot.

Verification Artifacts In Repo

These checks can be run directly from the repository today. Some are exact analytical comparisons, some are heritage reproductions, and some are interim product benchmarks. They should not all be interpreted as the same level of external credibility.

SAE 961452 Parity

SAE Technical Paper 961452 (Keller & Vogel, 1996) is the foundational V&V reference for SINDA/FLUINT — the NASA/DoD standard spacecraft thermal analyzer. SINDA/FLUINT achieved < 0.5% agreement on all cases.

This is legitimate analytical parity evidence for the lumped thermal core. It is not the same thing as published parity against Thermal Desktop, ESATAN-TMS, NASTRAN thermal, or Abaqus thermoelastic cases.

PharmaSat Mission Reproduction

PharmaSat was a NASA 1U CubeSat deployed from the ISS in May 2009 (~400 km, 51.6° inclination). Its thermal behavior was modeled with SatTherm and independently validated against Thermal Desktop and on-orbit telemetry. We reproduce SatTherm’s published orbit-averaged steady-state results using a 3-node Verixos model.

This is a documented flight-heritage reproduction chain, not a direct ingest of public raw NASA telemetry into Verixos. SatTherm itself agreed with the flight-validated Thermal Desktop model to within 4 °C, and Verixos falls within 5.4 K of SatTherm’s published midrange values for this simplified model tier.

What We Can And Cannot Claim Today

This is the most important section on the page. It is the line between credible engineering evidence and marketing overreach.

Known Limitations

We believe transparency builds trust. Here is what the Verixos solver does not currently validate to a production-credible standard.

External Validation Targets

These are the highest-value next steps for proving credibility beyond internal verification: public commercial-tool parity, hardware correlation, and flight or heritage correlation with enough context to be defensible.

Run the Tests Yourself

Most current verification artifacts are standalone TypeScript files. No running server or database is required for the core solver checks.

Citations

1. [1]NASA-STD-7009, Standard for Models and Simulations, credibility assessment framework.
2. [2]ECSS-E-ST-31C, Thermal Control General Requirements.
3. [3]Incropera, F.P. et al., Fundamentals of Heat and Mass Transfer, 7th Ed., Wiley, 2011.
4. [4]Cengel, Y.A., Ghajar, A.J., Heat and Mass Transfer, 5th Ed., McGraw-Hill, 2015.
5. [5]Howell, J.R. et al., Thermal Radiation Heat Transfer, 7th Ed., CRC Press, 2021.
6. [6]Gilmore, D.G. (Ed.), Spacecraft Thermal Control Handbook, Vol. 1, 2nd Ed., AIAA, 2002.
7. [7]NASA SP-8105, Spacecraft Thermal Control, May 1973.
8. [8]ECSS-E-HB-31-03A, Thermal Analysis Handbook, November 2016.
9. [9]Keller, J. & Vogel, M., "Validation of the SINDA/FLUINT Thermal Analyzer Code Using Several Analytical Solutions," SAE 961452, 1996.
10. [10]Allison, J.D., "A Thermal Analysis and Design Tool for Small Spacecraft," SJSU Master's Thesis, 2009.
11. [11]Allison, J.D. et al., "SatTherm," SSC09-VII-6, 23rd AIAA/USU Small Satellites Conference, 2009.
12. [12]Dassault Systèmes Abaqus verification and benchmark documentation (public pages).
13. [13]NASA thermal analyzer sample-problem library and thermal sample-problem reports available via NTRS.
14. [14]NASA FASTSAT-HSV01 thermal model correlation paper (public NTRS record).