Sincetheearlydaysofmannedspaceflight,hazardouseffectsofthespaceenvironmentonlivingorganismshavebeendisputed.WiththecontinuousmanningoftheInternationalSpaceStation,theplannedChi-nesespacestation,andrenewedinterestinreturningtotheMoonandsendingmannedflightstoMars,identifyingandaddressingthepotentialoutcomesoflong-termspaceexposuresiscriticallyimportant.