DC-Dc converters are increasing being used in space vehicles. The charged particles in the natural space environment degrade the electrical characteristics of electronic devices and can interact with sensitive regions of devices to trigger catastrophic failure mechanisms. It is shown that the Buck-Boost converter significantly degrades under total ionizing dose radiation environment. However, the effects of total ionizing dose on Buck, Boost and Cuk converters are not significant. Under the worst case single event burnout and single event gate rupture of power mosfet transistors, it is shown that the functional characteristics of Buck, Boost, Boost-Buck, Cuk and full bridge zero voltage switch converters may degrade considerably.