This thesis explores the work performed towards characterizing, understanding, and mitigating observed degradation in radio frequency and photonic integrated circuits and systems for use in high-radiation space environments. Specifically, work towards creating and characterizing integrated radiation-hardened by design complementary-metal-oxide-semiconductor transistors, and comparisons of electrical versus optical radiation-induced degradation in vertical-cavity photo-detectors, are explored. Additionally, comparisons between the radiation responses of different photonic interconnects (silicon vs. silicon-nitride), and potential mitigation techniques for the observed damage, are shown. Finally, the vulnerability of small-form resonator-based electro-optic modulators to transient radiation effects, and the implications of this increased sensitivity on photonic data links, is confirmed contrary to the perceived radiation transient hardness of photonic components.