Significant differences in dose prediction for Space Station arise depending on whether or not the magnetic field model is extrapolated into the future. The basis for these calculations is examined in detail, and the importance of the residual atmospheric layer at altitudes below 1,000 km, with respect to radiation attenuation is emphasized.Dosimetry results from shuttle flights are presented and compared with the computed results. It is recommended that, at this stage, no extrapolation of the magnetic field into the future be included in the calculations. A model adjustment, to replace this arbitrary procedure is presented. Dose predictions indicate that, at altitudes below 500 km and low inclination, and with nominal module wall thicknesses (.125 inch aluminum), orbit stay time of 90 days in Space Station are well within present radiation limit guidelines.