As humans step off their home planet into the surrounding solar system and beyond, they do not go alone. Machines have preceded them. And as people go into space, machines will go along. Of all the machines we have used and imagined, none have captured our interest and feelings so strongly as the class of machines called robots.

The International Space Station's new Canadarm2 robotic arm grasps a Spacelab pallet while Canadian mission specialist Chris A. Hadfield helps maneuver it into loading position while on a space walk.

But what exactly is meant by the term "robot"? Moreover, how is it decided that it is better to use a robot for a job rather than a human? What are robots like in the early twenty-first century and what they will be like in the future? Will humans ever become more robot-like?

What Are Robots?