A process and apparatus for separating element isotopes in space by heating a stream of raw materials using concentrated sunlight and ionizing radiation, followed by electromagnetic separation, and collection of the desired isotopes in appropriate receptacles. The unique design of this invention allows flexibility of implementation, very high separation efficiency, and minimal waste. The intent of collecting a multiplicity of isotopes simultaneously is a key feature of this invention. The goal for this work is to greatly reduce the cost of producing purified finished materials in space. This capability makes economical the fabrication of complex and large structures for space-based industry and habitation. This invention builds upon the sciences of plasma physics, ion separation, and microgravity processing, and incorporates new concepts of the integral design and efficient process operation, taking advantage of the peculiar properties of a microgravity environment. The output stream of pure isotopes can be directed, focused, and shuttered to allow the creation of composite materials, superlattices, or three-dimensional structures of almost any atomic and spatial configuration.