GaN nanowires were irradiated using a cyclotron at 5 MeV energy with a fluency of up to 3.38x10(15)/cm(2) protons. The resistance of the GaN was increased by 95% at a dose of 1.69x10(15)/cm(2) protons and then 116% at a dose of 3.38x10(15)/cm(2) protons because of the damage induced by the high energy protons. Cathodoluminescence of the GaN nanowires found a slight broadening of near band-edge emission and a dramatic decrease in the intensity of midgap transitions. These GaN-based nanomaterials have a potential in space technology because of their strong bonding energy compared to other material systems such as silicon and GaAs. Furthermore, the relatively small decrease in resistivity confirms the predicted robustness to proton irradiation of GaN nanowires compared to a GaN thin film.