In-space manufacturing (ISM) is an upcoming technology in the space industry. Unprecedented applications can be achieved by producing objects in space, as opposed to bringing objects to space that were produced on Earth. For solar arrays, this means that extremely large array sizes can be achieved, because with ISM the array size is not limited by the maximum payload volume of the launch vehicle. Additionally, the array can be lighter, because the structure does not need to withstand the harsh launch conditions. Additive manufacturing, wire based directed energy deposition in particular, was identified as the best in space manufacturing method for solar array structures. This thesis aims to find the best system to achieve this and investigate the limitations and challenges to applying metal additive manufacturing in space. A top-level system design is proposed and thermal, power and mechanical limitations are explored. This technology is still at a low TRL level and a lot of development is needed. Therefore, the most important points for future research are provided.