Review

Radiation risk mitigation in human space exploration: a primer, a vision, and the state of the art

¹ Department of Physics, University of Rome Tor Vergata, 00133, Rome, Italy
² INFN Sect. Roma Tor Vergata, Via Della Ricerca Scientifica, 00133, Rome, Italy
³ Radiation Biophysics and Radiobiology Laboratory, “A. Volta” Physics Department, Via Bassi 6, 27100, Pavia, Italy
⁴ Department of Biology and Biotechnologies “C. Darwin”, Sapienza University of Rome, P.Le A. Moro, 5, 00185, Rome, Italy
⁵ Department of Agricultural Sciences, University of Naples Federico II, Piazza Carlo Di Borbone N. 1, Portici, Naples, Italy
⁶ Dipartimento Di Fisica E Astronomia, Università Di Bologna, Viale Berti Pichat 6/2, 40136, Bologna, Italy
⁷ Department of Radiation Oncology, Miller School of Medicine, University of Miami, Miami, FL, USA
⁸ Dipartimento Di Scienze Di Base E Applicate Per L’Ingegneria, University of Rome La Sapienza, Rome, Italy
⁹ INFN, Sect. of Roma 1, Rome, Italy
¹⁰ Department of Physics “E. Pancini”, University of Naples Federico II, Via Cinthia, 80126, Naples, Italy
¹¹ INFN Sect. Napoli, Naples, Italy
¹² Institute of Crystallography, National Research Council, Strada Provinciale 35d, N. 9, 00010, Montelibretti, Rome, Italy
¹³ Department of Pharmacological and Biomolecular Sciences “R. Paoletti”, Università Degli Studi Di Milano, Via D. Trentacoste 2, 20134, Milan, Italy
¹⁴ Technology and Heath Department, Istituto Superiore Di Sanità, Rome, Italy
¹⁵ UOC Degenze Di Radioterapia Oncologica, Dipartimento Di Diagnostica Per Immagini E Radioterapia Oncologica, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
¹⁶ GSI Helmholtzzentrum Für Schwerionenforschung GmbH, Planckstraße 1, 64291, Darmstadt, Germany
¹⁷ Italian Space Agency, Via del Politecnico S.N.C., 00133, Rome, Italy

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Received: 18 August 2025
Accepted: 10 December 2025
Published online: 30 January 2026

Abstract

Human exploration beyond low Earth orbit poses unique health and operational challenges, with space radiation recognized as one of the most significant hazards. This comprehensive review examines the complex nature of the space radiation environment, its biological effects on humans and life support systems, and current strategies for risk assessment and mitigation. It details the composition and properties of galactic cosmic rays (GCRs) and solar particle events (SPEs), their interactions with spacecraft shielding, and the resulting biological impacts ranging from DNA damage to systemic effects including cancer, cardiovascular disease, and central nervous system impairments. Special emphasis is given to the combined effects of radiation and microgravity, which together alter cellular function and influence health outcomes. The paper also explores the effects of radiation on plants and microorganisms as biological components of bioregenerative life support systems (BLSS). The issue of radiation-induced degradation of food and pharmaceuticals is also considered. Existing and emerging countermeasures, encompassing passive and active shielding, pharmacological agents, nutrition, physiological adaptations like synthetic hibernation, and personalized risk assessment through targeted crew selection are critically reviewed. Additionally, the work highlights the importance of high-fidelity analog studies, space-based experiments, and advanced risk models integrating physical, biological, and operational data to inform future mission planning. Finally, the paper reviews existing infrastructures, experimental platforms, and European research programs, emphasizing the critical role of ground-based accelerators, space analog environments, and in-flight studies in advancing our understanding of radiation risks. By identifying key knowledge gaps and proposing a structured mitigation framework, this study presents a strategic roadmap for protecting human health and sustaining life during long-duration missions to the Moon, Mars, and beyond. (The review work described in the paper stems from the discussions within the working group on Radiation sponsored by the Italian Space Agency.)