Thermal management of space electronic devices has always posed a considerable challenge due to the adverse conditions of space environment. Copper, due to its thermal properties, is a key material in exchanging and dissipating heat in a space vessel. With the rising challenges and requirements for launching, so must these systems rise in performance and sustainability. Additive manufacturing (AM) stands as a major technology not only for producing highly complex geometries that will enhance performance but also for minimizing costs and lead times, by virtue of a highly customizable layer by layer production. Achieving high heat exchanging efficiency is a challenge the industry must face, and the ability to rapidly produce highly complex pure copper geometries stands out as a possible solution. However, one of the major drawbacks of AM copper is the susceptibility to internal defects such as porosity, which can have a preponderant effect on the final properties of the part. Therefore, this study aims to understand the impact of porosity and focuses on the production and characterization of pure copper via Material Extrusion (MEX). Several pure copper cylinders and subize E370 tensile specimens were printed, debinded and sintered. Non-destructive testing via microtomography was used to analyse the filament and the green (before sintering) and sintered 3D objects, and identify the defects, as well as the shape, location and amount of porosity. The production parameters adapted in order to induce porosity. After the sintering of all specimens, thermal conductivity, resistivity and density were assessed. Finally, the impact of the varying degree of porosity was further studied through tensile testing.