nt in this figure is the increasing severity of the environment with increasing orbit altitude for the low earth orbits and the effectiveness of shielding towards attenuating the effects of the environment. The low earth orbit total ionizing dose contribution is dominated by trapped proton effects for values of shielding thickness which are typical of most payload microelectronics devices; the benefits of additional shielding towards attenuating the dose is marginally effective. For locations having shielding conditions less than 2.5mm the dose level is dominated by the trapped electron contribution; the use of additional shielding is effective in reducing the total ionizing dose in these locations. The environment for geostationary satellite applications indicates the benefits 1E+08 1E+07 Geostationary 1E+06 1400 k 1E+05 750 km 1E+04 1E+03 Shielding [mm| Al] Figure 5-1. Total Ionizing Dose for LEO and GEO Applications which shielding provisions can achieve in attenuating the severity of this environment. Two issues of importance in considering the total ionizing dose in this environment are the potential of dose enhancement attributable to the interaction of energetic electrons with shielding materials, and the contributions to total ionizing dose which arise from solar particle events. Having established mission integrated dose levels for components to be utilized in systems, design for compatibility with the environment consists of selecting technologies and devices which exhibit adequate levels of tolerance, and developing applications design guidelines which consider any degradation in component performance which will occur over operating life due to mission integrated dose effects. Consideration must be given to the differences in radiation test environment utilized to evaluate component performance and tolerance, including delivered dose rate versus on-orbit dose rates, and the particle/photon species used to emulate the space environment. Dose rate effects are particularly important in light of enhanced l