 Space exploration is the discovery and exploration of celestial structures in outer space by means of evolving and growing space technology. While the study of space is carried out mainly by astronomers with telescopes, the physical exploration of space is conducted both by unmanned robotic space probes and human space flight. With the observation of objects in space, known as astronomy, predates reliable recorded history, it was the development of large and relatively efficient rockets during the mid-20th century that allowed physical space exploration to become a reality. Common rash inales for exploring space include advancing scientific research, national prestige, uniting different nations, ensuring the future survival of humanity, and developing military and strategic advantages against other countries. Space exploration has often been used as a proxy competition for geopolitical rivalries such as the Cold War. The early era of space exploration was driven by a space race between the Soviet Union and the United States. The launch of the first human-made object to orbit Earth, the Soviet Union's Sputnik one, on October 4, 1957, and the first moon landing by the American Apollo 11 mission on July 28, 1969 are often taken as landmarks for this initial period. The Soviet space program achieved many of the first milestones, including the first living being in orbit in 1957, the first human-space flight Yuri Gurgaren aboard Vostok-1 in 1961, the first spacewalk by Oleg Savinov on March 18, 1965, the first automatic landing on another celestial body in 1966, and the launch of the first space station Tsleut-1 in 1971. After the first 20 years of exploration, focus shifted from one-off flights to renewable hardware, such as the Space Shuttle Program, and from competition to cooperation as with the International Space Station ISS. With the substantial completion of the ISS to following SIS-133 in March 2011, plans for space exploration by the U.S. remain in flux. The Bush administration program for a return to the moon by 2023 was judged inadequately funded and unrealistic by an expert review panel reporting in 2009. For the Obama administration proposed a revision of constellation in 2010 to focus on the development of the capability for crewed missions beyond flow. With Forbit Leo envisioning extending the operation of the ISS beyond 2020, transfer in the development of launch vehicles for human crews from NASA to the private sector, and developing technology to enable missions to beyond Leo, such as Earth-Moon-L-1, the Moon, Earth-Sun-L-2, near-Earth asteroids, and Phobos Hermars. In the 2000s, the People's Republic of China initiated a successful manned space flight program, while the European Union, Japan, and India have also planned future crewed space missions. China, Russia, Japan, and India have advocated crewed missions to the Moon during the 21st century, while the European Union has advocated manned missions to both the Moon and Mars during the 28th and 21st century. From the 1990s onwards, private interests began promoting space tourism and then public space exploration of the Moon See Google Lunar X Prize.