Additive manufacturing is considered by many manufacturers to be part of the fourth industrial revolution. ESA's Advanced Manufacturing initiative aims to home in on emerging manufacturing technologies which open new industrial possibilities in terms of design freedom, streamlined production stages, and reduced cost, along with enhanced performance from the final product. Not only does additive manufacturing in space allow for the quick resupply of components, it also creates the opportunity to create objects such as nano satellites in space and launch them directly into low earth orbit from the ISS. Direct launching, and additive manufacturing in general, would save a significant amount of time and resources. Manufacturing components on an as needed basis will also increase the self-sufficiency and endurance of future space exploration missions.  The seven major AM methods have been analyzed for future use in space, and ranked via three types of criteria: cost, microgravity, and processing, for ISS, Lunar, and Martian based manufacturing. Findings indicate that direct energy deposition and material extrusion will be the most useful in advancing in-space manufacturing.