Over time, the radiation hardness that satellite manufacturers have been able to offer has greatly increased. Both the optimization of space systems in terms of the power/mass ratio, or the miniaturization of electronic devices, tends to increase the sensitivity of those systems to the space radiation environment. In order to mitigate the impact on the radiation hardness process, the first solution is to replace the rough shielding analysis by an accurate estimate of the real radiation constraint on the system. Historically, FASTRAD has been able to assist this industry.