A satellite or artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation (GPS), broadcasting, scientific research, and Earth observation. Additional military uses are reconnaissance, early warning, signals intelligence and, potentially, weapon delivery. Other satellites include the final rocket stages that place satellites in orbit and formerly useful satellites that later become defunct.
Space exploration is the use of astronomy and space technology to explore outer space. While the exploration of space is currently carried out mainly by astronomers with telescopes, its physical exploration is conducted both by uncrewed robotic space probes and human spaceflight. Space exploration, like its classical form astronomy, is one of the main sources for space science.
Space colonization is the process of establishing human settlements beyond Earth for prestige, commercial or strategic benefit, in contrast to space exploration for scientific benefit. Colonialism in this sense is multi-dimensional, including the exploitation of labor, resources and rights.
A spacecraft is a vehicle that is designed to fly and operate in outer space. Spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, planetary exploration, and transportation of humans and cargo. All spacecraft except single-stage-to-orbit vehicles cannot get into space on their own, and require a launch vehicle.
A space station is a spacecraft which remains in orbit and hosts humans for extended periods of time. It therefore is an artificial satellite featuring habitation facilities. The purpose of maintaining a space station varies depending on the program. Most often space stations have been research stations, but they have also served military or commercial uses, such as hosting space tourists.
Spaceflight is an application of astronautics to fly objects, usually spacecraft, into or through outer space, either with or without humans on board. Most spaceflight is uncrewed and conducted mainly with spacecraft such as satellites in orbit around Earth, but also includes space probes for flights beyond Earth orbit. Such spaceflights operate either by telerobotic or autonomous control. The first spaceflights began in the 1950s with the launches of the Soviet Sputnik satellites and American Explorer and Vanguard missions. Human spaceflight programs include the Soyuz, Shenzhou, the past Apollo Moon landing and the Space Shuttle programs. Other current spaceflight are conducted to the International Space Station and to China's Tiangong Space Station.
The space program of the People's Republic of China is about the activities in outer space conducted and directed by the People's Republic of China. The roots of the Chinese space program trace back to the 1950s, when, with the help of the newly allied Soviet Union, China began development of its first ballistic missile and rocket programs in response to the perceived American threats. Driven by the successes of Soviet Sputnik 1 and American Explorer 1 satellite launches in 1957 and 1958 respectively, China would launch its first satellite, Dong Fang Hong 1 in April 1970 aboard a Long March 1 rocket, making it the fifth nation to place a satellite in orbit.
Edward Everett Hale was an American author, historian, and Unitarian minister, best known for his writings such as "The Man Without a Country", published in Atlantic Monthly, in support of the Union during the Civil War. He was the grand-nephew of Nathan Hale, the American spy during the Revolutionary War.
Space burial is the launching of human remains into space. Missions may go into orbit around the Earth or to extraterrestrial bodies such as the Moon, or farther into space.
The Italian Space Agency is a government agency established in 1988 to fund, regulate and coordinate space exploration activities in Italy. The agency cooperates with numerous national and international entities who are active in aerospace research and technology.
The Soviet space program was the state space program of the Soviet Union, active from 1951 until the dissolution of the Soviet Union in 1991. Contrary to its American, European, and Chinese competitors, which had their programs run under single coordinating agencies, the Soviet space program was divided between several internally competing design bureaus led by Korolev, Kerimov, Keldysh, Yangel, Glushko, Chelomey, Makeyev, Chertok and Reshetnev. Several of these bureaus were subordinated to the Ministry of General Machine-Building. The Soviet space program served as an important marker of claims by the Soviet Union to its superpower status.
Private spaceflight refers to spaceflight developments that are not conducted by a government agency, such as NASA or ESA.
Artificial gravity is the creation of an inertial force that mimics the effects of a gravitational force, usually by rotation. Artificial gravity, or rotational gravity, is thus the appearance of a centrifugal force in a rotating frame of reference, as opposed to the force experienced in linear acceleration, which by the equivalence principle is indistinguishable from gravity. In a more general sense, "artificial gravity" may also refer to the effect of linear acceleration, e.g. by means of a rocket engine.
Spaceflight began in the 20th century following theoretical and practical breakthroughs by Konstantin Tsiolkovsky, Robert H. Goddard, and Hermann Oberth, each of whom published works proposing rockets as the means for spaceflight. The first successful large-scale rocket programs were initiated in Nazi Germany by Wernher von Braun. The Soviet Union took the lead in the post-war Space Race, launching the first satellite, the first animal, the first human and the first woman into orbit. The United States landed the first men on the Moon in 1969. Through the late 20th century, France, the United Kingdom, Japan, and China were also working on projects to reach space.
The following outline is provided as an overview of and topical guide to space exploration.
The concepts of space stations and space habitats feature in science fiction. The difference between the two is that habitats are larger and more complex structures intended as permanent homes for substantial populations, but the line between the two is fuzzy with significant overlap and the term space station is sometimes used for both concepts. The first such artificial satellite in fiction was Edward Everett Hale's "The Brick Moon" in 1869, a sphere of bricks 61 meters across accidentally launched into orbit around the Earth with people still onboard.
In 2013, the maiden spaceflight of the Orbital Sciences' Antares launch vehicle, designated A-ONE, took place on 13 April. Orbital Science also launched its first spacecraft, Cygnus, that docked with the International Space Station in late September 2013.
CAPSTONE is a lunar orbiter that is testing and verifying the calculated orbital stability planned for the Lunar Gateway space station. The spacecraft is a 12-unit CubeSat that is also testing a navigation system that is measuring its position relative to NASA's Lunar Reconnaissance Orbiter (LRO) without relying on ground stations. It was launched on 28 June 2022, arrived in lunar orbit on 14 November 2022, and was scheduled to orbit for six months. On 18 May 2023, it completed its primary mission to orbit in the near-rectilinear halo orbit for six months, but will stay on this orbit, continuing to perform experiments during an enhanced mission phase.
Cygnus NG-15, previously known as OA-15, was the fifteenth launch of the Northrop Grumman robotic resupply spacecraft Cygnus and its fourteenth flight to the International Space Station (ISS) under the Commercial Resupply Services (CRS) contract with NASA. The mission launched on 20 February 2021 at 17:36:50 UTC. This is the fourth launch of Cygnus under the CRS-2 contract.
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