Scientists examine a weld made on board the International Space Station. Experts argue that this technology is critical for future space exploration. So far, only a few experiments of this kind have been performed in space.
Astronauts working on the International Space Station made a weld that is currently being tested on Earth, informed the European Space Agency (ESA). Although it is only a centimeter long, its creation is a historic moment, experts say.
– If exploration space is to become truly sustainable and self-sustaining, then production in space must become widespread, and the ability to weld will be an important element of this. Therefore, we need to check whether it is easy to weld in space, said João Gandra, an engineer at ESA.
What welding in space looks like
Welding in space is completely different from the same process on Earth. For example, under the influence of normal gravity, convection currents in the air cool the metal, creating a so-called weld pool, which, when hardened, forms a weld. In microgravity conditions, molten metal behaves differently – it creates liquid drops that maintain a specific shape under the influence of surface tension.
In addition, metal is affected by other factors in space, such as radiation or vacuum. – Currently, we do not really understand how these factors may interact and what consequences they may have on the properties of the final product. We can run computer simulations, but we lack empirical data to calibrate and improve our predictions. That's why this spot weld is so valuable to us, adds João Gandra.
So far, only a few welding experiments have been carried out in space. The first one was carried out on the Soviet Soyuz-6 spacecraft in 1969, and the subsequent ones – on the American Skylab station and the Soviet Salyut-7 station, in 1973 and 1984, respectively. In the 1990s, American-Russian plans were made to develop a multifunctional welding tool for maintenance work carried out on the ISS. However, they were abandoned due to safety concerns and logistical difficulties.
Maciej Zieliński, Adam Ziemienowicz/PAP
The weld now examined was made using a device that emits a strong electron beam that heats the metal. A similar technique was used in the mentioned experiment carried out on board Soyuz-6.
Electron beam welding has several advantages. The beam can be precisely controlled, penetrates deep into the metal, and minimal energy is lost. However, this method can only be used in a high-quality vacuum, which makes electron beam welding ideal for use in space. Moreover, this system can also be used for cutting and 3D printing. Although the welding required a vacuum, it was carried out inside the International Space Station, in a special aluminum cylinder.
“A key element of the new space economy”
The experiment was initiated by the American startup ThinkOrbital and carried out with the participation of the British The Welding Institute.
– We hope to participate in further test flights aimed at increasingly ambitious welding operations. This campaign is perfectly in line with ESA's strategy to develop production and servicing methods in space. It is a key element of the new space economy and is another tool in humanity's arsenal moving towards further and longer space missions, concludes João Gandra.
Main photo source: Dima Zel/Shutterstock