This paper presents a case study of the potential application of additive manufacturing (AM) to produce a large-size radiator intended for use in the crew module of a human spaceflight. Traditionally, such radiators are made by welding metal tubes onto a sheet, which requires a lot of welding to go along the tubes’ path and around the bends. Overall, the welding process is laborious, skilled expertise is needed, and there is a significant risk of leaks at the welded connections. When 3D printing a radiator using the Laser Powder Bed Fusion (LPBF) technology, the component must be segmented into numerous pieces and then welded together to form the finished radiator component. The Design for Additive Manufacturing (DfAM) model has just two pipe welds per segment at the inlet and the outlet. In contrast, when divided into several segments, the conventional design had multiple joints along the pipes, which may result in multiple leak spots to take care of. Additionally, there is a weight decrease and a larger surface area in the DfAM model than in the conventional model. Additionally, there is no need for supports in the case of the DfAM model, and there is less distortion during its 3D printing. A study on heat transfer was carried out, and the results showed that the DfAM model results in more evenly dispersed heat.