Manned space flights are supported by the notion that humans have an innate need to explore the universe—in specially protected spacecrafts—but at great risk to life. Congress wants manned space travel to support an industry that builds the costly crafts. On the other hand, unmanned spacecrafts are supported by scientists who believe that robots, at this stage of space travel, can do anything better than humans can do in space, and send back data as effectively as humans. This chapter addresses the pro and con arguments regarding manned versus unmanned space travel.