Several international space agencies plan to send astronauts beyond low-Earth orbit in the coming decades to explore the Moon or other nearby planetary objects. Humans leaving the Earth's magnetosphere enter the solar wind, potentially exposing themselves to prompt solar energetic particle (SEP) events, which are sudden outbursts of energetic particle radiation of solar origin. Accurate warning of SEP radiation hazards through an operational forecasting system, even if only an hour in advance, allows contingency plans to be set in motion rapidly. The potential for expanding mission operations capabilities with such warnings has been acknowledged by the NASA Space Radiation Analysis Group at Johnson Space Center. As NASA gears up to send astronauts to the Moon and Mars, projected radiation doses on such long-term missions approach current career limits, so avoiding sudden exposure from SEP events becomes crucial.