Risk analyses for the solar particle events of August through December 1989

The solar particle events of August through December 1989, among the largest ever recorded, are analyzed to assess the potential hazards to humans on interplanetary missions from events of these types. Using the coupled neutron-proton space radiation transport computer code, BRYNTRN, risk estimates for the effects of exposures to the skin, ocular lens, and bone marrow are made for nominal thicknesses of the spacecraft aluminum shielding. Risk assessment in terms of absorbed dose is made for each event. Also presented are estimates of organ absorbed dose and dose equivalent for pairs of events which occurred within 30-day periods, and for the cumulative August through December 1989 period.