Welding is the technique of joining metal components most used by industry, both in manufacturing and in the recovery of parts and structures.
With the demand for productivity increase and metallurgical quality, new welding processes arise, favoring the appearance of applications previously neither imaginable. Similar to underwater welding, welding in space, outside the Earth’s atmosphere, presents the same challenge: Is it possible to construct complex structures in these environments with welding?
Although still scarcely used in practice, welding in space has already been a subject studied for many years. One can mention, for example, space welding experiments conducted in the 1960s by the United States and the former Soviet Union.
However, due to the scientific dispute generated by the Cold War, little has been divulged about the processes of welding and its application in space environment.
One thing is clear, the application of welding in space would greatly facilitate the maintenance of worn out equipment and structures, such as the International Space Station. Still, the high cost with the fuel needed to bring the spacecraft into orbit could be reduced, taking complex structures still dismantled into the Earth’s orbit.
The space environment has its own characteristics that need to be considered for the development of a welding process. These include, for example, vacuum, absence of gravity and the presence of constant ionizing radiation.
While the arc welding processes would require protective gases under pressure transported to space and the construction of closed chambers for the execution of the procedures, there are some other processes that prove very advantageous:
The process of electron beam welding, by already relying on a vacuum chamber, could be easily used in space. This process had experiments carried out in 1969, on a mission in the Soviet Soyuz spacecraft.
The laser welding process is also shown as an excellent alternative for the spatial application, using a light of high concentrated energy, allowing the application of welding with high metallurgical quality and welding speed.
The laser welding process is in constant development in the main universities and technological institutes all over the world, and presents itself as a promising process of processing materials in various applications, contributing to the increased control over the processing of materials.
Recent works seems to confirm this possibility, indicating an increase in penetration when the laser welding is done in a vacuum. In addition to welding, this process can also be used for cutting, machining and marking of materials.
In addition to the already mentioned fusion welding processes, one possibility is the friction welding processes, in particular the Friction Stir Welding. This process, as it does not require the fusion of materials for welding, is very promising to the space environment. However, because it deals with high torques involved, it may present an obstacle in running in a zero gravity environment.
Therefore, space welding is not a single merit for science fiction films, but a perfectly plausible application that will increasingly be in the minds and publications of the great researchers.
References:
Marques, P., V; Modonesi, P. J.; Bracarense, A., Q.; Soldagem: Fundamentos e Tecnologia, 4ª Edição, 2017, p. 355 – 357