The 20th century brought the most horrific weapons and most devastating wars in the history of human civilization. It also gave us the most breathtaking discoveries and technological breakthroughs, including the opening up of outer space to human reach. The commercialization of outer space is one of the most significant developments of our time, giving us an opportunity to put the richness of this medium to the betterment of human conditions on Earth on an increasingly widening scale. Technological advances have also made space more important militarily. A puzzle now is whether the commercialization of outer space facilitates international cooperation in the security realm or makes interstate relations more competitive in the fourth medium....