A closer look
Two completely clean and unoxidized pieces of the same metal will permanently fuse together if they touch in the vacuum of space. This phenomenon, known as cold welding, occurs because the atoms in each piece of metal have no way of knowing they belong to different objects without the barrier of an atmosphere or oxidation layer to keep them apart. It is a wildly inconvenient law of physics for aerospace engineers who have to meticulously coat all satellite components to prevent the entire multi-billion-dollar spacecraft from accidentally gluing itself together in orbit. Imagine spending twenty years designing a high-tech orbital telescope only to watch it instantly turn into a useless clump of fused aluminum just because two microscopic gears brushed against each other
