**Abstract**

Understanding the effect of radiation on materials is fundamental for space exploration. Energetic charged particles impacting materials create electronic excitations, atomic displacements, and nuclear fragmentation. Monte Carlo particle transport simulations are the most common approach for modeling radiation damage in materials. However, radiation damage is a multiscale problem, both in time and in length, an aspect treated by the Monte Carlo simulations only to a limited extent. In this chapter, after introducing the Monte Carlo particle transport method, we present a multiscale approach to study different stages of radiation damage which allows for the synergy between the electronic and nuclear effects induced in materials. We focus on cumulative displacement effects induced by radiation below the regime of hadronic interactions. We then discuss selected studies of radiation damage in materials of importance and potential use for the exploration and settlement on the Moon, ranging from semiconductors to alloys and from polymers to the natural regolith. Additionally, we overview some of the novel materials with outstanding properties, such as low weight, increased radiation resistance, and self-healing capabilities with a potential to reduce mission costs and improve prospects for extended human exploration of extraterrestrial bodies.

**Keywords:** space radiation, multiscale modeling, defects, semiconductors, alloys, composites, solar cells, habitat on the Moon
