Learning 3D Hypersonic Flow with Physics-Enhanced Neural Fields: A Case Study on the Orion Reentry Capsule

Abstract

We develop a 3D aerothermodynamic simulator for the Orion reentry capsule at hypersonic speeds, a timely case study given its role in upcoming lunar missions. The large computational meshes required for these scenarios make traditional computational fluid dynamics impractical for full-mission performance prediction and control. In this work, we propose physics-enhanced 3D neural fields for predicting steady hypersonic flow around aerodynamic bodies. The model maps spatial coordinates and angle of attack to pressure, temperature, and velocity components. We enhance the base model with Fourier positional feature mappings, which allow it to capture the sharp discontinuities typical of hypersonic flows, and further constrain the solution by imposing no-slip and isothermal wall conditions. We compare our proposed approach to other surrogate alternatives, such as graph neural networks, and demonstrate its superior performance in capturing the steep gradients ubiquitous in this regime. Our formulation yields a continuous and computationally efficient aerothermodynamic surrogate that supports rapid exploration of operating conditions based on angle of attack variation under realistic flight profiles. While we focus on Orion, the proposed framework provides a general methodology for data-driven simulation in 3D hypersonic aerothermodynamics.

Figures (12)

• Figure 1: Orion, Artemis I, on flight day 13 (Nov. 28, 2022). Credit: NASA.
• Figure 2: Orion CM Outer Mold Line. Figure from Brown2010OrionTransonic.
• Figure 3: Converged 3D mesh of the Orion CM geometry at $M = 5$, $\alpha = 0^{\circ}$. Centreplane cross-section overlaid with Mach number contour.
• Figure 4: Flow field prediction error with respect to CFD ground truth on the $z/d=0$ plane at $\alpha=15^{\circ}$ (validation AoA), comparing neural field models with $(e,f,g,h)$ and without Fourier features $(a,b,c,d)$, as in Table \ref{['tab:fourier_sigma_ablation']}. In terms of columns, we have the horizontal $v_x/U_{\infty}$ (a, e), vertical velocity $v_y/U_{\infty}$ (b, f), pressure $p/p_{\infty}$ (c, g), and temperature $T/T_{\infty}$ (d, h). Contours show the normalized percentage error.
• Figure 5: Shock gradient predictions along the $y/d=0$ symmetry line and plane $z/d=0$ for $\alpha=15^{\circ}$. (a) $v_x/U_{\infty}$, (b) $v_y/U_{\infty}$, (c) $p/p_{\infty}$, (d) $T/T_{\infty}$. The shaded gray area marks the capsule body.