"The MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Loss and Energization) project has two focussed and synergistic aims: to advance scientific research on radiation belt dynamics; and to enhance data exploitation of European space missions through combined use of European and US spacecraft measurements and ground-based observations.MAARBLE employs multi-spacecraft monitoring of the geospace environment, complemented by ground-based monitoring, in order to analyze and assess the physical mechanisms leading to radiation belt particle energization and loss. Particular attention is paid to the role of ULF/VLF waves. A database containing properties of the waves will be created and made available to the scientific community. Based on the wave database, a statistical model of the wave activity dependent on the level of geomagnetic activity, solar wind forcing, and magnetospheric region will be developed.Multi-spacecraft particle measurements will be Incorporated into data assimilation tools, leading to new understanding of the causal relationships between ULF/VLF waves and radiation belt dynamics. Data assimilation techniques have been proven as a valuable tool in the field of radiation belts, able to guide 'the best' estimate of the state of a complex system.It should also be stressed that radiation belt dynamics has direct impacts on spacecraft and on humans in space. Most satellites operate in regions where they can be exposed to intense fluxes of extremely energetic radiation belt particles. In addition, the orbit of the International Space Station is such that the exposure of astronauts to relativistic radiation belt electrons is a serious concern. Consequently, understanding the radiation belt environment has important practical applications in the areas of spacecraft operations, spacecraft-system design, mission planning and astronaut safety. Therefore MAARBLE will bear results beneficial to both robotic space exploration and manned spaceflight."