The militarization of space involves the placement and development of weaponry and military technology in outer space. The early exploration of space in the mid-20th century had, in part, a military motivation, as the United States and the Soviet Union used it as an opportunity to demonstrate ballistic-missile technology and other technologies having the potential for military application. Outer space has since been used as an operating location for military spacecraft such as imaging and communications satellites, and some ballistic missiles pass through outer space during their flight. , known deployments of weapons stationed in space include only the Almaz space-station armament and pistols such as the TP-82 Cosmonaut survival pistol (for post-landing, pre-recovery use). Cold War During the Cold War, the world's two great superpowers—the Soviet Union and the United States of America—spent large proportions of their GDP on developing military technologies. The drive to place objects in orbit stimulated space research and started the Space Race. In 1957, the USSR launched the first artificial satellite, Sputnik 1. By the end of the 1960s, both countries regularly deployed satellites. Reconnaissance satellites were used by militaries to take accurate pictures of their rivals' military installations. As time passed the resolution and accuracy of orbital reconnaissance alarmed both sides of the iron curtain. Both the United States and the Soviet Union began to develop anti-satellite weapons to blind or destroy each other's satellites. Directed-energy weapons, kamikaze-style satellites, as well as orbital nuclear explosives were researched with varying levels of success. Spy satellites were, and continue to be, used to monitor the dismantling of military assets in accordance with arms control treaties signed between the two superpowers. To use spy satellites in such a manner is often referred to in treaties as "national technical means of verification". The superpowers developed ballistic missiles to enable them to use nuclear weaponry across great distances.