The Radiation Environments of Outer-Planet Missions

The outer-planets spacecraft must contend with a variety of radiation environments during its lengthy mission in deep space. These environments include onboard nuclear emitters, such as radio-isotope thermoelectric generators, and natural sources--Earth's Van Allen belt, galactic cosmic radiation, solar flares, and a trapped radiation belt at Jupiter. This paper shows the effects of mission and spacecraft parameters on the neutron and proton fluences that might cause permanent damage to the electronic devices from these sources. It is concluded that electronic systems will function satisfactorily during these missions provided that appropriate precautions are taken.