What Happens When Two Metal Objects Touch In Space?
On Earth, if two pieces of metal touch one another, they remain separate objects. However, this is not always true in space. If the metal materials have exactly the same composition, they can sometimes join together spontaneously. However, if there are any differences in composition, it will not occur. Also, a substantial amount of force has to be applied to the two pieces of metal to cause it to occur.
The phenomenon is called “cold welding”, and it is rare. However, it is still a cause for concern among space engineers. In fact, it’s believed to have caused satellite malfunctions in the past.
Why Does This Not Occur On Earth?
On Earth, metals oxidize. This means that they do not remain completely pure. Their edges contain oxidized materials, and the amount of oxidation varies across any metal surface. Thus, you would almost never find two truly identical metallic surfaces on the surface of the Earth.
However, in a vacuum, oxidation does not occur. Thus, it is possible for two metal surfaces to be identical. Usually, this is still not the case. Oxidation that occurred on Earth where the metals were manufactured is typically sufficient to prevent cold welding. Though, there are circumstances when it can occur.
Furthermore, in the future, materials may be manufactured and constructed in space. If the metallic objects were never exposed to air, they would remain exceptionally pure, and this would make cold welding occur far more reliably. In fact, cold welding could even be used to join pieces of metals manufactured in space.
This could actually make construction in space easier. In fact, it could allow segments of metal to be joined together without visible joints. That’s because welding would not be necessary, as the principle of cold welding could be used to join the components together. Though, unwanted cold welding is a challenge that space engineers work to overcome today and will throughout the future of space travel.
Can Cold Welding Occur In A Vacuum Chamber?
It is possible to cold weld two pieces of metal together in a vacuum chamber. In fact, this is sometimes done to fuse metallic objects. Though, it is critical that the metals are very quickly put into the chamber after being manufactured or are not highly susceptible to oxidation. Otherwise, it is not likely to be effective.