Interplanetary crew dose estimates for worst case solar particle events based on historical data for the Carrington flare of 1859

Over the past two decades, hypothetical models of “worst-case” solar particle event (SPE) spectra have been proposed in order to place an upper bound on radiation doses to critical body organs of interplanetary crews on deep space missions. These event spectra are usually formulated using hypothetical extrapolations of space measurements for previous large events. Here we take a different approach. Recently reported analyses of ice core samples indicate that the Carrington flare of 1859 is the largest event observed in the past 500 years. These ice core data yield estimates of the proton fluence for energies greater than 30 MeV, but provide no other spectrum information. Assuming that the proton energy distribution for such an event is similar to that measured for other recent, large events, interplanetary crew doses are estimated for these hypothetical worst case SPE spectra. These estimated doses are life threatening unless substantial shielding is provided.     

Synopsis of troposphere and lower stratosphere

The use of different types of balloons for the investigation of the troposphere and lower stratosphere is reviewed with a special emphasis on the application for the next 10 years. The instrumentation currently flown aboard balloons or under development is described. Some possible scientific objectives of such balloon experiments are presented. The specific applications of the different types of balloons available within the next few years for scientific flights are discussed.