Space exploration is the ongoing discovery and exploration of celestial structures in outer space by means of continuously evolving and growing space technology.
Space technology – technology developed by space science or the aerospace industry for use in spaceflight, satellites, or space exploration.
Outer space, deep space, or just space, is the void that exists between celestial bodies, including the Earth.
The sky is everything that lies above the surface of the Earth, including the atmosphere and outer space.
While the study of space is carried out mainly by astronomers with telescopes, the physical exploration of space is conducted both by unmanned robotic probes and human spaceflight.
An astronomer is a scientist in the field of astronomy who concentrates their studies on a specific question or field outside of the scope of Earth.
A telescope is an optical instrument that aids in the observation of remote objects by collecting electromagnetic radiation.
A robotic spacecraft is an uncrewed spacecraft, usually under telerobotic control.
While 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 early 20th century that allowed physical space exploration to become a reality.
Astronomy, a natural science, is the study of celestial objects and processes, the physics, chemistry, and evolution of such objects and processes, and more generally all phenomena that originate outside the atmosphere of Earth.
Recorded history or written history is a historical narrative based on a written record or other documented communication.
A rocket is a missile, spacecraft, aircraft or other vehicle that obtains thrust from a rocket engine.
Common rationales 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.
A sovereign state is, in international law, a nonphysical juridical entity that is represented by one centralised government that has sovereignty over a geographic area.
Space exploration has often been used as a proxy competition for geopolitical rivalries such as the Cold War.
The Cold War was a state of political and military tension after World War II between powers in the Western Bloc and powers in the Eastern Bloc.
The early era of space exploration was driven by a "Space Race" between the Soviet Union and the United States.
The United States of America, commonly referred to as the United States or America, is a federal republic composed of 50 states, a federal district, five major self-governing territories, and various possessions.
The Soviet Union, officially the Union of Soviet Socialist Republics, abbreviated to USSR, was a socialist state on the Eurasian continent that existed from 1922 to 1991.
The Space Race was a 20th-century competition between two Cold War rivals, the Soviet Union and the United States, for supremacy in spaceflight capability.
The launch of the first human-made object to orbit Earth, the Soviet Union's Sputnik 1, on 4 October 1957, and the first Moon landing by the American Apollo 11 mission on 20 July 1969 are often taken as landmarks for this initial period.
The Apollo program, also known as Project Apollo, was the third United States human spaceflight program carried out by the National Aeronautics and Space Administration, which accomplished landing the first humans on the Moon from 1969 to 1972.
Earth is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrestrial planets, and the only astronomical object known to harbor life.
The colonization of the Moon is the proposed establishment of permanent human communities or robotic industries on the Moon.
The Soviet space program achieved many of the first milestones, including the first living being in orbit in 1957, the first human spaceflight in 1961, the first spacewalk on 18 March 1965, the first automatic landing on another celestial body in 1966, and the launch of the first space station in 1971.
A space station, also known as an orbital station or an orbital space station, is a spacecraft capable of supporting a crew, which is designed to remain in space for an extended period of time and for other spacecraft to dock.
The Soviet space program comprised the rocketry and space exploration programs conducted by the former Soviet Union from the 1930s until its dissolution in 1991.
Extravehicular activity is any activity done by an astronaut or cosmonaut outside a spacecraft beyond the Earth's appreciable atmosphere.
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.
The Space Shuttle program, officially called the Space Transportation System, was the United States government's manned launch vehicle program from 1981 to 2011, administered by NASA and officially beginning in 1972.
The Space Shuttle was a partially reusable low Earth orbital spacecraft system operated by the U.S. National Aeronautics and Space Administration, as part of the Space Shuttle program.
With the substantial completion of the ISS following STS-133 in March 2011, plans for space exploration by the USA remain in flux.
STS-133 was the 133rd mission in NASA's Space Shuttle program; during the mission, Space Shuttle Discovery docked with the International Space Station.
Constellation, a Bush Administration program for a return to the Moon by 2020 was judged inadequately funded and unrealistic by an expert review panel reporting in 2009.
The Review of United States Human Space Flight Plans Committee was a group reviewing the human spaceflight plans of the United States.
The Obama Administration proposed a revision of Constellation in 2010 to focus on the development of the capability for crewed missions beyond low Earth orbit, envisioning extending the operation of the ISS beyond 2020, transferring 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 L1, the Moon, Earth–Sun L2, near-Earth asteroids, and Phobos or Mars orbit.
The National Aeronautics and Space Administration is an independent agency of the executive branch of the United States federal government responsible for the civilian space program as well as aeronautics and aerospace research.
In celestial mechanics, the Lagrangian points are positions in an orbital configuration of two large bodies where a small object affected only by gravity can maintain a stable position relative to the two large bodies.
A low Earth orbit is an orbit around Earth with an altitude between 160 kilometers, and 2,000 kilometers.
In the 2000s, the People's Republic of China initiated a successful manned spaceflight program, while the European Union, Japan, and India have also planned future manned space missions.
The European Union is a politico-economic union of 28 member states that are located primarily in Europe.
India, officially the Republic of India, is a country in South Asia.
China, Russia, Japan, and India have advocated manned missions to the Moon during the 21st century, while the European Union has advocated manned missions to both the Moon and Mars during the 20/21st century.
The Aurora programme is a human spaceflight programme of the European Space Agency established in 2001.
From the 1990s onwards, private interests began promoting space tourism and then private space exploration of the Moon.