The approach of the ‘Interplanetary Meteoroid Environment for eXploration’ (IMEX) project is to build a model of meteoroid streams throughout the inner solar system. Our motivation for this model is the impact hazard to spacecraft. An understanding of the interplanetary environment, including the dust environment, is crucial for the planning of spacecraft missions in the inner solar system. Particles striking a spacecraft with high velocities can cause damage leading to the impairment or even failure of the spacecraft or its subsystems. Depending on the impactors size the effects range from degradation of functional surfaces, such as optical systems or solar arrays, to cratering and structural penetration. Ad- ditionally, secondary effects such as electromagnetic pulses generated by the plasma release from impacts can interfere or even destroy sensitive electronics. Manned space activities are especially vulnerable to any damage caused by meteoroid impacts because of their much lower tolerance level, large cross sections and long exposure times. Such a model can also be used to study meteor showers on Earth and at other planets; to develop a map of cometary trails in the sky, which can be used to launch a search for these trails; and to study the timescales on which streams are dispersed by planetary perturbations and other effects.