Quantum–Classical Optimization of Space Radiation Shielding Materials under Solar Particle Event Conditions

Abstract

The harmful effects of space radiation on biological systems and electronic equipment pose a major challenge for long-duration human missions in deep-space environments. Space radiation primarily consists of Galactic Cosmic Rays (GCR) and Solar Energetic Particles (SEP), with Solar Particle Events (SPE) causing intense, short-term radiation exposure. Minimizing radiation impact through effective shielding is therefore essential for safe space exploration. In this study, the shielding performance of aluminium, lithium hydride (LiH), and polyethylene was evaluated in a free-space SPE environment using the OLTARIS (On-Line Tool for the Assessment of Radiation in Space) platform. Dose-equivalent values were calculated to assess and compare the radiation attenuation capabilities of these materials under realistic SPE conditions relevant to space applications. To optimize material selection, the shielding problem was formulated as a Quadratic Unconstrained Binary Optimization (QUBO) model. The OLTARIS-derived dose-equivalent data were mapped onto an Ising Hamiltonian, enabling quantum-classical hybrid optimization. The Variational Quantum Eigensolver (VQE) and the Quantum Approximate Optimization Algorithm (QAOA) were implemented to determine shielding configurations that minimize radiation exposure. The results obtained from quantum optimization closely matched the OLTARIS simulation outcomes, demonstrating the reliability of hybrid quantum approaches for shielding optimization. This work highlights the potential of integrating classical radiation transport simulations with quantum algorithms for advanced space radiation protection strategies.