What is it about?
At the 78 km point on Varda’s W-2 reentry we ran both DSMC and CFD, pulled line-of-sight shock-layer properties, and computed Vis-NIR spectral radiance with two radiation codes — HARA and NEQAIR — against OSPREE’s in situ spectra. The two emission models disagree in both magnitude and shape: NEQAIR underpredicts spectral radiance by up to two orders of magnitude relative to HARA above 500 nm. We trace that gap to NEQAIR’s non-Boltzmann N2 emission band model.
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Why is it important?
Even with the same flow field, the radiation solver can swing the answer by orders of magnitude. Anyone comparing NEQAIR and HARA for Vis-NIR capsule shock-layer emission needs to know that N2 band treatment is not a detail; it can dominate agreement with flight data. The journal article is the archival place that documents that discrepancy against the OSPREE measurement.
Perspectives
This is the archival version of SciTech 2026-1469. Treat the conference paper as the early snapshot; use this JTHT article for the expanded HARA-versus-NEQAIR comparison at 78 km and the non-Boltzmann N2 diagnosis. Companion reading: the Acta Astronautica DSMC paper and SciTech 2026-0307 (trajectory-wide model comparisons).
Zach Davis
Space Dynamics Laboratory
Read the Original
This page is a summary of: Radiative Emissions Model Comparisons Against In Situ Emissions Data of the Varda Reentry Capsule, Journal of Thermophysics and Heat Transfer, September 2026, American Institute of Aeronautics and Astronautics (AIAA),
DOI: 10.2514/1.t7520.
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