Artificial hip, c. 1975

The human body is a hostile environment for anything that does not naturally belong in it. The immune system ensures, for example, that pathogens do not penetrate the body or that if they have penetrated they are removed as quickly as possible. That is just as well, because otherwise we would not survive for very long. That physical rejection, however, becomes a problem if one wants to replace a part. This artificial hip, for example, is made of a special metal: titanium. This material has two major advantages: it is very strong and it does not activate the immune system. The artificial hip is attached to the natural bone with glue. These techniques are a spin-off from developments in space travel. So that thanks to the spaceships that we fire into space medicine is able to replace worn-out bones with spare parts.