Volatile nitrogen study of Chang’e-5 and Chang’e-6 soils

Lunar soils, formed in the absence of a long-lived atmosphere and a global magnetic field, record volatile inputs from both solar-wind implantation and planetary impacts. For most species, including water and noble gases, solar-wind implantation dominates. Nitrogen, however, behaves fundamentally differently. We present stepwise-heating nitrogen measurements of Chang’e-5 and Chang’e-6 lunar soils, providing the first paired mid-latitude samples from the lunar near side and far side. The Chang’e soils show that most trapped nitrogen is supplied by micro-impactor delivery rather than solar-wind implantation. However, when integrated with low-latitude Apollo and Luna datasets, the combined results reveal that spatial variations in nitrogen isotopic compositions across the Moon are primarily controlled by variations in solar-wind flux.