  A software toolkit for the simulation of activation background for high
energy detectors onboard satellites is presented on behalf of the HERMES-SP
collaboration. The framework employs direct Monte Carlo and analytical
calculations allowing computations two orders of magnitude faster and more
precise than a direct Monte Carlo simulation. The framework was developed in a
way that the model of the satellite can be replaced easily. Therefore the
framework can be used for different satellite missions. As an example, the
proton induced activation background of the HERMES CubeSat is quantified.
