20 Greatest Astronauts of the World

There have been many astronauts who have made tremendous contributions to our knowledge of space. But asking ?who is the most famous?? is somewhat tricky. For one, it?s a bit subjective. And second, it can be hard to objectively measure just how important and individuals? contributions really are. Surely, all astronauts are deserving of recognition and respect for their bravery and contributions to the pursuit of knowledge.