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. They also occur in nuclear explosions, and near nuclear reactors and other sources of radiation.
There are many techniques which can achieve hardening. The MRAM, Magnetoresistive random access memory, is proposed as the solution to long-lasting electronic memory. This is the heart of radiation resistance, because if the system memory is undamaged, the system can be rebooted.