3D printing3D printing, or additive manufacturingAdditive manufacturing, is an ordinary yet disruptive innovation transforming traditional manufacturing with potential usage on reusable rocket enginesReusable rocket engines by using superalloys to create high-efficiency material composition. 3D printing3D printing builds intricate designs and allows process controlsProcess control previously unthinkable. Additive manufacturingAdditive manufacturing technology has significantly reduced the time and complexity of complicated assemblies, allowing parts to be made on demand for reusable rockets. This technology has also changed cost structures by eliminating the need for non-recurring investments in molds, tools, and setups while minimizing wasteWastes and supporting sustainabilitySustainability. This paper provides the Selective Laser SinteringSelective laser sintering (SLS) 3D printing roadmap3D printing roadmap, application, decomposition into subsystems, characterizationCharacterization through Figures of MeritFigures of merit (FOMs), and the 3D printing3D printing processesProcess (modeling, printing, post-processing). The paper draws attention to intricate shape designs and enhanced producibility of complex parts. The covered principles include stereolithography, digital light processing, and selective laser sinteringSelective laser sintering.