So, What if Guardians avoid radiation because, in order to recover or resurrect, Ghosts replicate our DNA and Cell’s genetic material, but due to DNA/Genetic Malfunctions when coming into contact with Ionizing radiation. It causes a much higher chance of developing mutations and disorders due to the bad DNA being replicated and spread like a Malignant Tumor?
Also, maybe the reason the Cosmodrome is radioactive (And thus, closed off by the Vanguard)
Is because the Siege engine crashed, and at some point, the Warhead that powered the dang thing ended up spreading Radiation everywhere?