3D printing (additive manufacturing) does have many advantages in space applications. It has great appeal. If the technology is mature and applied directly in space, it can be used locally, or some garbage can be recycled as raw materials. The space base is just around the corner, and the space industry will certainly feed back the earth, producing the goods that human beings need to live on Earth, and improving the quality of human life. At the same time, it can reduce the dependence of space exploration on the ground launch capability. In order to realize large-scale application of space by using 3D printing, 3D printing of metal materials must be realized, and metal additive manufacturing in space can greatly expand the scope of human exploration of the universe. Let's answer the advantages and problems of space metal 3D printing. The advantages of space 3D printing in space must be compared with the ground: 1. Space station low-orbit rail and lunar surface vacuum environment can avoid oxidation, no need to vacuum or use shielding gas; 2. Space station micro-gravity environment requires only a small workbench It is possible to manufacture large-sized components; 3. The low-temperature environment helps to refine the grains (which may cause other problems) and improve performance. The possible problems in metal 3D printing in space are as follows: 1. The technical maturity problem, there are still many problems on the ground, such as dimensional accuracy, surface roughness and internal defects, etc.; 2. Space environment adaptability. For example, in the microgravity environment, the sintering method needs to be powdered. The use of powder in the microgravity environment may be dangerous, and the droplet transfer of the fuse method is also difficult. The vacuum environment determines that some methods on the ground are difficult to implement; And the issue of energy supply, the development of energy depends on the development of space solar power plants, but if the test is carried out in the space station, the ground supply of raw materials is required, and the construction of the outer space base may have no directly available raw materials. The above is only the problem of metal 3D printing itself, but the 3D printed parts need to be directly applied in space, and the difficulty is far more than the 3D printing technology. The reasons are as follows: 1. The current parts obtained by metal additive manufacturing are still Need to reserve a certain amount of margin, need to process, the corresponding processing equipment; 2, metal additive manufacturing parts quality evaluation and inspection issues. Metal additive manufacturing can be said to be an extension of welding technology. In order to apply in the space for welding parts, it is necessary to carry out a large number of tests on welding samples, such as fiber structure observation, mechanical property test, sealing test, etc. Welding process test, sample processing equipment and test equipment, as well as non-destructive testing of the final test piece, such as X-ray inspection, ultrasonic inspection, etc., and evaluation of performance and service behavior in space environment, on this basis An evaluation standard has been established, that is, what level of ground quality is achieved to ensure the service life and reliability of space service. Space-processed parts, if served in space, also require such a system. For example, the KRT semiconductor material processed by the former Soviet salute space station is used on an infrared observer that returns to the Earth and is processed into parts and sent to the space station for installation in the melting furnace, rather than directly used in space to obtain materials. Therefore, the space application of 3D printing is not a simple 3D printing itself, but it is necessary to move the entire set of related industrial systems to the sky to establish testing and service standards for production parts in a space environment. But this is not to say that we are not currently conducting research on spatial 3D printing. It is because of the prospects that are valuable and problematic, so we need to work hard to explore.