What fundamental materials are protected within Permanently Shadowed Regions (PSRs) near the lunar South Pole?

Water ice mixed with the regolith

The primary driver for the intense exploration interest in the Permanently Shadowed Regions (PSRs) surrounding the lunar South Pole is the presumed presence of water ice. These deep craters maintain near-total darkness because the Moon's low axial tilt ensures the Sun never illuminates their interiors, creating natural deep-freeze storage lockers. Observations using techniques like radar and neutron spectrometry have detected spectral signatures of hydrogen, providing strong evidence that significant quantities of water ice are mixed within the lunar soil, or regolith, inside these shadowed areas. This ice is critically important because it represents a potential in-situ resource utilization (ISRU) asset, as water can be processed into hydrogen and oxygen, which are essential for producing breathable air and rocket propellant, thereby reducing the massive logistical costs associated with launching these materials from Earth.