1 If Two Pieces Of Metal Touch In Space They Stick Together
Wow, I love science. It manages to throw amazing little gem up nearly every day. This just happens to be one of them. If two pieces of metal touch in space, that’s two identical pieces, such as two pieces of copper or two pieces of iron, they will stick together as if they were welded. Well, not as if they were welded, exactly the same, if not better than if they were welded. The process that causes this phenomenon is called cold welding.
Cold welding was discovered in the 1940’s. As the name suggests, it’s the process of welding two pieces of metal together without any heat. With normal welding, two pieces of metal are joined by applying heat to a joint. The heat fuses the two pieces together as one. Cold welding on the other hand requires several factors to work. Firstly, the two pieces must have a similar composition, such as copper and copper. Next, they must be in perfect condition. No rust, oil or grease. In other words, no foreign material at all can be present on the two pieces. Thirdly, a vacuum, not the household kind, is needed. The kind of vacuum that is in space. When all these things are present the two will fuse together, forming one solid piece. The reason for this is that the atoms in the metals can’t tell if they are on different pieces of metal, and form just one continuous piece. If there is a foreign object, such as rust, oil or grease, the atoms kind of know that the two pieces are different, and will not stick together.
Now, as you could imagine, this could be a bit of a problem for NASA and other space agencies. The space craft and tools that they use are made out of metals. They need to be strong and durable to survive launch, orbit and re-entry. Plastic and other materials just wouldn’t cut it, especially if repairs were needed to be carried out. However, as we have said, metals will stick together in space, which could mean that a wrench could stick to the space craft, or even a pair of scissors might become completely useless because the moving parts would fuse together. But the NASA geeks had this little problem sorted.
What NASA does is give the tools a little coating of plastic or other thin coating material to prevent the two surfaces from physically touching. This provides a thin coat to tools and other objects that are used in space. But the coating isn’t really that necessary.
The reason that NASA doesn’t have to coat the metal tools so if two pieces of metal touch in space they wont stick together is because the metal is forged here on Earth. Earth isn’t the perfect environment for metals. The oxidizing atmosphere immediately contaminates the surfaces of the metals. When they are sent into space, this contamination will prevent the two from sticking together. B ut if the metal is forged in space, they will stick like shit to a blanket.