[en] This chapter has provided a brief review of the many computer methods which are now available for performing analyses of particle fluxes and radiation doses in simple and complex models of spacecraft structures. When using simple geometries for routine dose computation, the sphere case is preferable to the slab case unless the use of the latter can be justified by the location of a specific component in the spacecraft. Shielding in a single-slab model is relatively good in most directions. The use of the programs described in this chapter allows an assessment to be made of the environment and doses in spacecraft, considering the mission and structural materials and geometry. Their use is recommended as an integral part of the detailed spacecraft design phase. The ESABASE/RADIATION module is designed as an easy-to-use tool for calculating mission radiation environments, using the UNIRAD suite of programs and the resulting dose in a complex model of the spacecraft geometry using the DOSRAD sectoring program; see Fig. 12.4. Alternatively, CHARGE or SHIELD can be combined with SIGMA to compute doses in complex geometries. Single-event upset sensitivity may be assessed with the CREME program together with device data, or other programs now becoming available