text: Radiation hardening is a method of designing and testing electronic components and systems to make them resistant to damage or malfunctions caused by ionizing radiation ( particle radiation and high-energy electromagnetic radiation ) , such as would be encountered in outer space , high-altitude flight , around nuclear reactors , particle accelerators , or during nuclear accidents or nuclear warfare .
simplified: Radiation hardening is the designing of electronic parts and systems so they can withstand the damage done by ionizing radiation . Such radiation occurs in outer space and when flying at high altitudes in the Van Allen radiation belts .