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110-404: 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

220-570: A domino effect known as Kessler syndrome . NASA's Orbital Debris Program tracks over 25,000 objects larger than 10 cm diameter in LEO, while the estimated number between 1 and 10 cm is 500,000, and the number of particles bigger than 1 mm exceeds 100 million. The particles travel at speeds up to 7.8 km/s (28,000 km/h; 17,500 mph), so even a small impact can severely damage a spacecraft. [REDACTED]  This article incorporates public domain material from websites or documents of

330-736: A launch vehicle (carrier rocket). On a sub-orbital spaceflight , a space vehicle enters space and then returns to the surface without having gained sufficient energy or velocity to make a full Earth orbit . For orbital spaceflights , spacecraft enter closed orbits around the Earth or around other celestial bodies . Spacecraft used for human spaceflight carry people on board as crew or passengers from start or on orbit ( space stations ) only, whereas those used for robotic space missions operate either autonomously or telerobotically . Robotic spacecraft used to support scientific research are space probes . Robotic spacecraft that remain in orbit around

440-404: A semi-major axis of 8,413 km (5,228 mi). For circular orbits, this in turn corresponds to an altitude of 2,042 km (1,269 mi) above the mean radius of Earth, which is consistent with some of the upper altitude limits in some LEO definitions. The LEO region is defined by some sources as a region in space that LEO orbits occupy. Some highly elliptical orbits may pass through

550-421: A spaceport (cosmodrome), which may be equipped with launch complexes and launch pads for vertical rocket launches and runways for takeoff and landing of carrier airplanes and winged spacecraft. Spaceports are situated well away from human habitation for noise and safety reasons. ICBMs have various special launching facilities. A launch is often restricted to certain launch windows . These windows depend upon

660-496: A sub-orbital spaceflight the spacecraft reaches space and then returns to the atmosphere after following a (primarily) ballistic trajectory. This is usually because of insufficient specific orbital energy , in which case a suborbital flight will last only a few minutes, but it is also possible for an object with enough energy for an orbit to have a trajectory that intersects the Earth's atmosphere, sometimes after many hours. Pioneer 1

770-512: A "time buffer" and substantially widened the allowable launch windows . The parking orbit gave the crew and controllers time to thoroughly check out the spacecraft after the stresses of launch before committing it for a long journey to the Moon. Robotic missions do not require an abort capability and require radiation minimalization only for delicate electronics, and because modern launchers routinely meet "instantaneous" launch windows, space probes to

880-599: A 15.2 metres (50 ft) CanadaArm1 , an upgraded version of which is used on the International Space Station . The heat shield (or Thermal Protection System ) of the orbiter, used to protect it from extreme levels of heat during atmospheric reentry and the cold of space, was made up of different materials depending on weight and how much heating a particular area on the shuttle would receive during reentry, which ranged from over 2,900 °F (1,600 °C) to under 700 °F (370 °C). The orbiter

990-563: A blunt shape, do not usually contain much more fuel than needed, and they do not possess wings unlike spaceplanes . They are the simplest form of recoverable spacecraft, and so the most commonly used. The first such capsule was the Vostok capsule built by the Soviet Union, that carried the first person in space, Yuri Gagarin . Other examples include the Soyuz and Orion capsules, built by

1100-457: A collision risk to the many LEO satellites. No human spaceflights other than the lunar missions of the Apollo program (1968-1972) and the 2024 Polaris Dawn have taken place beyond LEO. All space stations to date have operated geocentric within LEO. A wide variety of sources define LEO in terms of altitude . The altitude of an object in an elliptic orbit can vary significantly along

1210-443: A counter measure to United States bomber planes in the 1950s. The Tsiolkovsky-influenced Sergey Korolev became the chief rocket designer, and derivatives of his R-7 Semyorka missiles were used to launch the world's first artificial Earth satellite , Sputnik 1 , on October 4, 1957. The U.S., after the launch of Sputnik and two embarrassing failures of Vanguard rockets , launched Explorer 1 on February 1, 1958. Three years later,

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1320-416: A flight that normally lasts over twenty hours , could be traversed in less than one hour. While no company offers this type of transportation today, SpaceX has revealed plans to do so as early as the 2020s using Starship . Suborbital spaceflight over an intercontinental distance requires a vehicle velocity that is only a little lower than the velocity required to reach low Earth orbit. If rockets are used,

1430-451: A launch tower and flame trench. It is surrounded by equipment used to erect, fuel, and maintain launch vehicles. Before launch, the rocket can weigh hundreds of tons. The Space Shuttle Columbia , on STS-1 , weighed 2030 metric tons (4,480,000 lb) at takeoff. The most commonly used definition of outer space is everything beyond the Kármán line , which is 100 kilometers (62 mi) above

1540-553: A liftoff thrust of 2,800,000 pounds-force (12 MN), which soon increased to 3,300,000 pounds-force (15 MN) per booster, and were fueled by a combination of PBAN and APCP , the Space Shuttle Orbiter , with 3 RS-25 engines that used a liquid oxygen / liquid hydrogen propellant combination, and the bright orange throwaway Space Shuttle external tank from which the RS-25 engines sourced their fuel. The orbiter

1650-595: A liquid-fueled rocket on March 16, 1926. During World War II , the first guided rocket, the V-2 , was developed and employed as a weapon by Nazi Germany . During a test flight in June 1944, one such rocket reached space at an altitude of 189 kilometers (102 nautical miles), becoming the first human-made object to reach space. At the end of World War II, most of the V-2 rocket team, including its head, Wernher von Braun , surrendered to

1760-571: A planetary body are artificial satellites . To date, only a handful of interstellar probes , such as Pioneer 10 and 11 , Voyager 1 and 2 , and New Horizons , are on trajectories that leave the Solar System . Orbital spacecraft may be recoverable or not. Most are not. Recoverable spacecraft may be subdivided by a method of reentry to Earth into non-winged space capsules and winged spaceplanes . Recoverable spacecraft may be reusable (can be launched again or several times, like

1870-611: A pre-programmed list of operations that will be executed unless otherwise instructed. A robotic spacecraft for scientific measurements is often called a space probe or space observatory . Many space missions are more suited to telerobotic rather than crewed operation, due to lower cost and risk factors. In addition, some planetary destinations such as Venus or the vicinity of Jupiter are too hostile for human survival, given current technology. Outer planets such as Saturn , Uranus , and Neptune are too distant to reach with current crewed spaceflight technology, so telerobotic probes are

1980-417: A rendezvous with Intelsat-901 on 25 February 2020. It will remain with the satellite until 2025 before the satellite is moved to a final graveyard orbit and the vehicle does a rendezvous with another satellite. The other one launched on an Ariane 5 rocket on 15 August 2020. A spacecraft astrionics system comprises different subsystems, depending on the mission profile. Spacecraft subsystems are mounted in

2090-491: A satellite into a LEO, and a satellite there needs less powerful amplifiers for successful transmission, LEO is used for many communication applications, such as the Iridium phone system . Some communication satellites use much higher geostationary orbits and move at the same angular velocity as the Earth as to appear stationary above one location on the planet. Unlike geosynchronous satellites , satellites in low orbit have

2200-441: A small field of view and can only observe and communicate with a fraction of the Earth at a given time. This means that a large network (or constellation ) of satellites is required to provide continuous coverage. Satellites at lower altitudes of orbit are in the atmosphere and suffer from rapid orbital decay , requiring either periodic re-boosting to maintain stable orbits, or the launching of replacements for those that re-enter

2310-678: A spacecraft of their own, the CST-100 , commonly referred to as Starliner , but a crewed flight is yet to occur. China developed, but did not fly Shuguang , and is currently using Shenzhou (its first crewed mission was in 2003). Except for the Space Shuttle and the Buran spaceplane of the Soviet Union, the latter of which only ever had one uncrewed test flight, all of the recoverable crewed orbital spacecraft were space capsules . The International Space Station , crewed since November 2000,

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2420-549: A stable low Earth orbit is about 7.8 km/s (4.8 mi/s), which translates to 28,000 km/h (17,000 mph). However, this depends on the exact altitude of the orbit. Calculated for a circular orbit of 200 km (120 mi) the orbital velocity is 7.79 km/s (4.84 mi/s), but for a higher 1,500 km (930 mi) orbit the velocity is reduced to 7.12 km/s (4.42 mi/s). The launch vehicle's delta-v needed to achieve low Earth orbit starts around 9.4 km/s (5.8 mi/s). The pull of gravity in LEO

2530-433: A subset of LEO. These orbits, with low orbital inclination , allow rapid revisit times over low-latitude locations on Earth. Prograde equatorial LEOs also have lower delta-v launch requirements because they take advantage of the Earth's rotation. Other useful LEO orbits including polar orbits and Sun-synchronous orbits have a higher inclinations to the equator and provide coverage for higher latitudes on Earth. Some of

2640-652: Is a joint venture between Russia, the United States, Canada and several other countries. Uncrewed spacecraft are spacecraft without people on board. Uncrewed spacecraft may have varying levels of autonomy from human input; they may be remote controlled , remote guided or even autonomous , meaning they have a pre-programmed list of operations, which they will execute unless otherwise instructed. Many space missions are more suited to telerobotic rather than crewed operation, due to lower cost and lower risk factors. In addition, some planetary destinations such as Venus or

2750-442: Is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder ; it creates a communication channel between a source transmitter and a receiver at different locations on Earth . Communications satellites are used for television , telephone , radio , internet , and military applications. Many communications satellites are in geostationary orbit 22,300 miles (35,900 km) above

2860-491: Is done by a set of orbital maneuvers called space rendezvous . After rendezvousing with the space station, the space vehicle then docks or berths with the station. Docking refers to joining of two separate free-flying space vehicles, while berthing refers to mating operations where an inactive vehicle is placed into the mating interface of another space vehicle by using a robotic arm . Vehicles in orbit have large amounts of kinetic energy. This energy must be discarded if

2970-887: Is effective mainly because of its ability to sustain thrust even as the atmosphere thins. Many ways to reach space other than rocket engines have been proposed. Ideas such as the space elevator , and momentum exchange tethers like rotovators or skyhooks require new materials much stronger than any currently known. Electromagnetic launchers such as launch loops might be feasible with current technology. Other ideas include rocket-assisted aircraft/spaceplanes such as Reaction Engines Skylon (currently in early stage development), scramjet powered spaceplanes, and RBCC powered spaceplanes. Gun launch has been proposed for cargo. On some missions beyond LEO (Low Earth Orbit) , spacecraft are inserted into parking orbits, or lower intermediary orbits. The parking orbit approach greatly simplified Apollo mission planning in several important ways. It acted as

3080-586: Is impossible. To date several academics have studied intergalactic travel in a serious manner. Spacecraft are vehicles designed to operate in space. The first 'true spacecraft' is sometimes said to be Apollo Lunar Module , since this was the only crewed vehicle to have been designed for, and operated only in space; and is notable for its non-aerodynamic shape. Spacecraft today predominantly use rockets for propulsion , but other propulsion techniques such as ion drives are becoming more common, particularly for uncrewed vehicles, and this can significantly reduce

3190-541: Is known as Kessler syndrome . There are several terms that refer to a flight into or through outer space . A space mission refers to a spaceflight intended to achieve an objective. Objectives for space missions may include space exploration , space research , and national firsts in spaceflight. Space transport is the use of spacecraft to transport people or cargo into or through outer space. This may include human spaceflight and cargo spacecraft flight. The first theoretical proposal of space travel using rockets

3300-647: Is more fuel-efficient for a craft to burn its fuel as close as possible to its periapsis (lowest point); see Oberth effect . Astrodynamics is the study of spacecraft trajectories, particularly as they relate to gravitational and propulsion effects. Astrodynamics allows for a spacecraft to arrive at its destination at the correct time without excessive propellant use. An orbital maneuvering system may be needed to maintain or change orbits. Non-rocket orbital propulsion methods include solar sails , magnetic sails , plasma-bubble magnetic systems , and using gravitational slingshot effects. The term "transfer energy" means

3410-455: Is not generally recognized by the public that the increase in potential energy required to pass the Kármán line is only about 3% of the orbital energy (potential plus kinetic energy) required by the lowest possible Earth orbit (a circular orbit just above the Kármán line.) In other words, it is far easier to reach space than to stay there. On May 17, 2004, Civilian Space eXploration Team launched

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3520-496: Is only slightly less than on the Earth's surface. This is because the distance to LEO from the Earth's surface is much less than the Earth's radius. However, an object in orbit is in a permanent free fall around Earth, because in orbit the gravitational force and the centrifugal force balance each other out. As a result, spacecraft in orbit continue to stay in orbit, and people inside or outside such craft continuously experience weightlessness . Objects in LEO orbit Earth between

3630-590: Is the fifth spacecraft put on an escape trajectory leaving the Solar System . Voyager 1 , Voyager 2 , Pioneer 10 , Pioneer 11 are the earlier ones. The one farthest from the Sun is Voyager 1 , which is more than 100 AU distant and is moving at 3.6 AU per year. In comparison, Proxima Centauri , the closest star other than the Sun, is 267,000 AU distant. It will take Voyager 1 over 74,000 years to reach this distance. Vehicle designs using other techniques, such as nuclear pulse propulsion are likely to be able to reach

3740-426: Is the height required by the international organization Fédération Aéronautique Internationale to count as a spaceflight. This altitude is called the Kármán line . In particular, in the 1940s there were several test launches of the V-2 rocket , some of which reached altitudes well over 100 km. As of 2016, only three nations have flown crewed spacecraft: USSR/Russia, USA, and China. The first crewed spacecraft

3850-626: Is to be replaced by expendable rockets such as the Space Launch System and ULA 's Vulcan rocket, as well as the commercial launch vehicles. Scaled Composites ' SpaceShipOne was a reusable suborbital spaceplane that carried pilots Mike Melvill and Brian Binnie on consecutive flights in 2004 to win the Ansari X Prize . The Spaceship Company built a successor SpaceShipTwo . A fleet of SpaceShipTwos operated by Virgin Galactic

3960-549: The Deep Space Network . A space telescope or space observatory is a telescope in outer space used to observe astronomical objects. Space telescopes avoid the filtering and distortion of electromagnetic radiation which they observe, and avoid light pollution which ground-based observatories encounter. They are divided into two types: satellites which map the entire sky ( astronomical survey ), and satellites which focus on selected astronomical objects or parts of

4070-399: The International Space Station and Tiangong space station. Some spacecrafts can operate as both a crewed and uncrewed spacecraft. For example, the Buran spaceplane could operate autonomously but also had manual controls, though it never flew with crew onboard. Other dual crewed/uncrewed spacecrafts include: SpaceX Dragon 2 , Dream Chaser , and Tianzhou . A communications satellite

4180-440: The International Space Station : Russian Progress , American SpaceX Dragon 2 and Cygnus . Chinese Tianzhou is used to supply Tiangong space station . Space probes are robotic spacecraft that are sent to explore deep space, or astronomical bodies other than Earth. They are distinguished from landers by the fact that they work in open space, not on planetary surfaces or in planetary atmospheres. Being robotic eliminates

4290-841: The SpaceX Dragon and the Space Shuttle orbiters ) or expendable (like the Soyuz ). In recent years, more space agencies are tending towards reusable spacecraft. Humanity has achieved space flight, but only a few nations have the technology for orbital launches : Russia ( Roscosmos ), the United States ( NASA ), the member states of the European Space Agency , Japan ( JAXA ), China ( CNSA ), India ( ISRO ), Taiwan ( TSA ), Israel ( ISA ), Iran ( ISA ), and North Korea ( NADA ). In addition, several private companies have developed or are developing

4400-484: The Tsiolkovsky rocket equation , can be used to find the total Δ v {\displaystyle \Delta v} , or potential change in velocity. This formula, which is still used by engineers, is a key concept of spaceflight. Spaceflight became a practical possibility with the work of Robert H. Goddard 's publication in 1919 of his paper A Method of Reaching Extreme Altitudes . His application of

4510-461: The USSR made one orbit around the Earth. In official Soviet documents, there is no mention of the fact that Gagarin parachuted the final seven miles. As of 2020, the only spacecraft regularly used for human spaceflight are Soyuz , Shenzhou , and Crew Dragon . The U.S. Space Shuttle fleet operated from April 1981 until July 2011. SpaceShipOne has conducted three human suborbital space flights. On

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4620-836: The Voskhod , Soyuz , flown uncrewed as Zond/L1 , L3 , TKS , and the Salyut and Mir crewed space stations . Other American crewed spacecraft include the Gemini spacecraft , the Apollo spacecraft including the Apollo Lunar Module , the Skylab space station, the Space Shuttle with undetached European Spacelab and private US Spacehab space stations-modules, and the SpaceX Crew Dragon configuration of their Dragon 2 . US company Boeing also developed and flown

4730-457: The de Laval nozzle to liquid-fuel rockets improved efficiency enough for interplanetary travel to become possible. After further research, Goddard attempted to secure an Army contract for a rocket-propelled weapon in the first World War but his plans were foiled by the November 11, 1918 armistice with Germany . After choosing to work with private financial support, he was the first to launch

4840-666: The dissolution of the USSR , prevented any further flights of Buran. The Space Shuttle was subsequently modified to allow for autonomous re-entry in case of necessity. Per the Vision for Space Exploration , the Space Shuttle was retired in 2011 mainly due to its old age and high cost of program reaching over a billion dollars per flight. The Shuttle's human transport role is to be replaced by SpaceX 's SpaceX Dragon 2 and Boeing 's CST-100 Starliner . Dragon 2's first crewed flight occurred on May 30, 2020. The Shuttle's heavy cargo transport role

4950-528: The equator , so that the satellite appears stationary at the same point in the sky; therefore the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track the satellite. Others form satellite constellations in low Earth orbit , where antennas on the ground have to follow the position of the satellites and switch between satellites frequently. The high frequency radio waves used for telecommunications links travel by line of sight and so are obstructed by

5060-490: The satellite bus and may include attitude determination and control (variously called ADAC, ADC, or ACS), guidance, navigation and control (GNC or GN&C), communications (comms), command and data handling (CDH or C&DH), power (EPS), thermal control (TCS), propulsion, and structures. Attached to the bus are typically payloads . Spaceflight Spaceflights include the launches of Earth observation and telecommunications satellites, interplanetary missions ,

5170-862: The American Orbiting Astronomical Observatory , OAO-2 launched in 1968, and the Soviet Orion 1 ultraviolet telescope aboard space station Salyut 1 in 1971. Space telescopes avoid the filtering and distortion ( scintillation ) of electromagnetic radiation which they observe, and avoid light pollution which ground-based observatories encounter. The best-known examples are Hubble Space Telescope and James Webb Space Telescope . Cargo spacecraft are designed to carry cargo , possibly to support space stations ' operation by transporting food, propellant and other supplies. Automated cargo spacecraft have been used since 1978 and have serviced Salyut 6 , Salyut 7 , Mir ,

5280-472: The CEO of SpaceX, estimated in a tweet that 8 launches would be needed to completely refuel a Starship in low Earth orbit , extrapolating this from Starship's payload to orbit and how much fuel a fully fueled Starship contains. To land on bodies without an atmosphere, such as the Moon, Starship will fire its engines and thrusters to slow down. The Mission Extension Vehicle is a robotic spacecraft designed to prolong

5390-403: The Earth's surface. (The United States defines outer space as everything beyond 50 miles (80 km) in altitude.) Rocket engines remain the only currently practical means of reaching space, with planes and high-altitude balloons failing due to lack of atmosphere and alternatives such as space elevators not yet being built. Chemical propulsion, or the acceleration of gases at high velocities,

5500-645: The Gemini program ended just before the Apollo 1 tragedy. Following multiple uncrewed test flights of the Saturn 1B and the Saturn V , the U.S. launched the crewed Apollo 7 mission into low earth orbit . Shortly after its successful completion, the U.S. launched Apollo 8 (first mission to orbit the moon), Apollo 9 (first Apollo mission to launch with both the CSM and the LEM ) and Apollo 10 (first mission to nearly land on

5610-459: The GoFast rocket on a suborbital flight, the first amateur spaceflight. On June 21, 2004, SpaceShipOne was used for the first privately funded human spaceflight . Point-to-point, or Earth to Earth transportation, is a category of sub-orbital spaceflight in which a spacecraft provides rapid transport between two terrestrial locations. A conventional airline route between London and Sydney ,

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5720-557: The LEO region near their lowest altitude (or perigee ) but are not in a LEO orbit because their highest altitude (or apogee ) exceeds 2,000 km (1,243 mi). Sub-orbital objects can also reach the LEO region but are not in a LEO orbit because they re-enter the atmosphere . The distinction between LEO orbits and the LEO region is especially important for analysis of possible collisions between objects which may not themselves be in LEO but could collide with satellites or debris in LEO orbits. The mean orbital velocity needed to maintain

5830-459: The Moon and developed continuous crewed human presence in space with a series of space stations , ranging from the Salyut program to the International Space Station . Rockets are the only means currently capable of reaching orbit or beyond. Other non-rocket spacelaunch technologies have yet to be built, or remain short of orbital speeds. A rocket launch for a spaceflight usually starts from

5940-423: The Moon and other planets generally use direct injection to maximize performance by limiting the boil off of cryogenic propellants . Although some might coast briefly during the launch sequence, they do not complete one or more full parking orbits before the burn that injects them onto an Earth escape trajectory. The escape velocity from a celestial body decreases as the distance from the body increases. However, it

6050-420: The Moon, Mars, and potentially beyond. It is intended to enable long duration interplanetary flights for a crew of up to 100 people. It will also be capable of point-to-point transport on Earth, enabling travel to anywhere in the world in less than an hour. Furthermore, the spacecraft will be used to refuel other Starship vehicles to allow them to reach higher orbits to and other space destinations. Elon Musk ,

6160-499: The Solar System , these are Voyager 1 , Voyager 2 , Pioneer 10 , Pioneer 11 , and New Horizons . The identical Voyager probes , weighing 721.9 kilograms (1,592 lb), were launched in 1977 to take advantage of a rare alignment of Jupiter , Saturn , Uranus and Neptune that would allow a spacecraft to visit all four planets in one mission, and get to each destination faster by using gravity assist . In fact,

6270-517: The Soviet Union and NASA , respectively. Spaceplanes are spacecraft that are built in the shape of, and function as, airplanes . The first example of such was the North American X-15 spaceplane, which conducted two crewed flights which reached an altitude of over 100 kilometres (62 mi) in the 1960s. This first reusable spacecraft was air-launched on a suborbital trajectory on July 19, 1963. The first reusable orbital spaceplane

6380-552: The Sputnik launch was a single event, it marked the start of the Space Age . Apart from its value as a technological first, Sputnik 1 also helped to identify the upper atmospheric layer 's density, by measuring the satellite's orbital changes. It also provided data on radio -signal distribution in the ionosphere . Pressurized nitrogen in the satellite's false body provided the first opportunity for meteoroid detection. Sputnik 1

6490-471: The Sun as of August 2023. NASA provides real time data of their distances and data from the probe’s cosmic ray detectors. Because of the probe’s declining power output and degradation of the RTGs over time, NASA has had to shut down certain instruments to conserve power. The probes may still have some scientific instruments on until the mid-2020s or perhaps the 2030s. After 2036, they will both be out of range of

6600-514: The USA on the 20th anniversary of Yuri Gagarin 's flight, on 12 April 1981. During the Shuttle era, six orbiters were built, all of which flown in the atmosphere and five of which flown in space. The Enterprise was used only for approach and landing tests, launching from the back of a Boeing 747 and gliding to deadstick landings at Edwards AFB, California . The first Space Shuttle to fly into space

6710-434: The USSR launched Vostok 1, carrying cosmonaut Yuri Gagarin into orbit. The US responded with the suborbital launch of Alan Shepard on May 5, 1961, and the orbital launch of John Glenn on February 20, 1962. These events were followed by a pledge from U.S. President John F. Kennedy to go to the moon and the creation of the Gemini and Apollo programs. After successfully performing a rendezvous and docking and an EVA ,

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6820-581: The United States, and were expatriated to work on American missiles at what became the Army Ballistic Missile Agency , producing missiles such as Juno I and Atlas . The Soviet Union , in turn, captured several V2 production facilities and built several replicas, with 5 of their 11 rockets successfully reaching their targets. (This was relatively consistent with Nazi Germany's success rate.) The Soviet Union developed intercontinental ballistic missiles to carry nuclear weapons as

6930-432: The ability to deorbit themselves. This becomes a major issue when large numbers of uncontrollable spacecraft exist in frequently used orbits, increasing the risk of debris colliding with functional satellites. This problem is exacerbated when large objects, often upper stages, break up in orbit or collide with other objects, creating often hundreds of small, hard to find pieces of debris. This problem of continuous collisions

7040-621: The artificial objects in outer space are in LEO, peaking in number at an altitude around 800 km (500 mi), while the farthest in LEO, before medium Earth orbit (MEO), have an altitude of 2,000 kilometers, about one-third of the radius of Earth and near the beginning of the inner Van Allen radiation belt . The term LEO region is used for the area of space below an altitude of 2,000 km (1,200 mi) (about one-third of Earth's radius). Objects in orbits that pass through this zone, even if they have an apogee further out or are sub-orbital , are carefully tracked since they present

7150-433: The atmosphere. The effects of adding such quantities of vaporized metals to Earth's stratosphere are potentially of concern but currently unknown. The LEO environment is becoming congested with space debris because of the frequency of object launches. This has caused growing concern in recent years, since collisions at orbital velocities can be dangerous or deadly. Collisions can produce additional space debris, creating

7260-521: The back of a Boeing 747 SCA and gliding to deadstick landings at Edwards AFB, California . The first Space Shuttle to fly into space was Columbia , followed by Challenger , Discovery , Atlantis , and Endeavour . Endeavour was built to replace Challenger when it was lost in January 1986. Columbia broke up during reentry in February 2003. The first autonomous reusable spaceplane

7370-461: The curve of the Earth. The purpose of communications satellites is to relay the signal around the curve of the Earth allowing communication between widely separated geographical points. Communications satellites use a wide range of radio and microwave frequencies . To avoid signal interference, international organizations have regulations for which frequency ranges or "bands" certain organizations are allowed to use. This allocation of bands minimizes

7480-455: The denser part of the atmosphere and below the inner Van Allen radiation belt . They encounter atmospheric drag from gases in the thermosphere (approximately 80–600 km above the surface) or exosphere (approximately 600 km or 400 mi and higher), depending on orbit height. Satellites in orbits that reach altitudes below 300 km (190 mi) decay quickly due to atmospheric drag. Equatorial low Earth orbits ( ELEO ) are

7590-480: The different orbiters had differing weights and thus payloads, with Columbia being the heaviest orbiter, Challenger being lighter than Columbia but still heavier than the other three. The orbiter structure was mostly composed of aluminium alloy. The orbiter had seven seats for crew members, though on STS-61-A the launch took place with 8 crew onboard. The orbiters had 4.6 metres (15 ft) wide by 18 metres (59 ft) long payload bays and also were equipped with

7700-647: The first generation of Starlink satellites used polar orbits which provide coverage everywhere on Earth. Later Starlink constellations orbit at a lower inclination and provide more coverage for populated areas. Higher orbits include medium Earth orbit (MEO), sometimes called intermediate circular orbit (ICO), and further above, geostationary orbit (GEO). Orbits higher than low orbit can lead to early failure of electronic components due to intense radiation and charge accumulation. In 2017, " very low Earth orbits " ( VLEO ) began to be seen in regulatory filings. These orbits, below about 450 km (280 mi), require

7810-409: The general spacecraft categories. This is a list of these spacecraft. Starship is a spacecraft and second stage under development by American aerospace company SpaceX . Stacked atop its booster, Super Heavy , it composes the identically named Starship super heavy-lift space vehicle . The spacecraft is designed to transport both crew and cargo to a variety of destinations, including Earth orbit,

7920-426: The life on another spacecraft. It works by docking to its target spacecraft, then correcting its orientation or orbit. This also allows it to rescue a satellite which is in the wrong orbit by using its own fuel to move its target to the correct orbit. The project is currently managed by Northrop Grumman Innovation Systems. As of 2023, 2 have been launched. The first launched on a Proton rocket on 9 October 2019, and did

8030-409: The moon). These events culminated with the first crewed moon landing, Apollo 11 , and six subsequent missions, five of which successfully landed on the moon. Spaceflight has been widely employed by numerous government and commercial entities for placing satellites into orbit around Earth for a broad range of purposes. Certain government agencies have also sent uncrewed spacecraft exploring space beyond

8140-406: The nearest star significantly faster. Another possibility that could allow for human interstellar spaceflight is to make use of time dilation , as this would make it possible for passengers in a fast-moving vehicle to travel further into the future while aging very little, in that their great speed slows down the rate of passage of on-board time. However, attaining such high speeds would still require

8250-584: The need for expensive, heavy life support systems (the Apollo crewed Moon landings required the use of the Saturn V rocket that cost over a billion dollars per launch, adjusted for inflation) and so allows for lighter, less expensive rockets. Space probes have visited every planet in the Solar System and Pluto , and the Parker Solar Probe has an orbit that, at its closest point, is in the Sun's chromosphere . There are five space probes that are escaping

8360-402: The only way to explore them. Telerobotics also allows exploration of regions that are vulnerable to contamination by Earth micro-organisms since spacecraft can be sterilized. Humans can not be sterilized in the same way as a spaceship, as they coexist with numerous micro-organisms, and these micro-organisms are also hard to contain within a spaceship or spacesuit. The first uncrewed space mission

8470-426: The orbit. Even for circular orbits , the altitude above ground can vary by as much as 30 km (19 mi) (especially for polar orbits ) due to the oblateness of Earth's spheroid figure and local topography . While definitions based on altitude are inherently ambiguous, most of them fall within the range specified by an orbit period of 128 minutes because, according to Kepler's third law , this corresponds to

8580-399: The position of celestial bodies and orbits relative to the launch site. The biggest influence is often the rotation of the Earth. Once launched, orbits are normally located within relatively constant flat planes at a fixed angle to the axis of the Earth, and the Earth rotates within this orbit. A launch pad is a fixed structure designed to dispatch airborne vehicles. It generally consists of

8690-402: The remainder heats the atmosphere. The Mercury , Gemini , and Apollo capsules splashed down in the sea. These capsules were designed to land at relatively low speeds with the help of a parachute. Soviet/Russian capsules for Soyuz make use of a big parachute and braking rockets to touch down on land. Spaceplanes like the Space Shuttle land like a glider . After a successful landing,

8800-426: The rendezvouses and dockings with space stations , and crewed spaceflights on scientific or tourist missions. Spaceflight can be achieved conventionally via multistage rockets , which provide the thrust to overcome the force of gravity and propel spacecraft onto suborbital trajectories . If the mission is orbital , the spacecraft usually separates the first stage and ignites the second stage , which propels

8910-470: The risk of signal interference. Cargo or resupply spacecraft are robotic spacecraft that are designed specifically to carry cargo , possibly to support space stations ' operation by transporting food, propellant and other supplies. Automated cargo spacecraft have been used since 1978 and have serviced Salyut 6 , Salyut 7 , Mir , the International Space Station and Tiangong space station. As of 2023, three different cargo spacecraft are used to supply

9020-519: The rocket that launched the probes (the Titan IIIE ) could not even send the probes to the orbit of Saturn , yet Voyager 1 is travelling at roughly 17 km/s (11 mi/s) and Voyager 2 moves at about 15 km/s (9.3 mi/s) kilometres per second as of 2023. In 2012, Voyager 1 exited the heliosphere, followed by Voyager 2 in 2018. Voyager 1 actually launched 16 days after Voyager 2 but it reached Jupiter sooner because Voyager 2

9130-454: The same way as a spaceship, as they coexist with numerous micro-organisms, and these micro-organisms are also hard to contain within a spaceship or spacesuit. Multiple space probes were sent to study Moon, the planets, the Sun, multiple small Solar System bodies (comets and asteroids). Special class of uncrewed spacecraft is space telescopes , a telescope in outer space used to observe astronomical objects. The first operational telescopes were

9240-504: The shuttle was a rather dangerous system, with fragile heat shielding tiles, some being so fragile that one could easily scrape it off by hand, often having been damaged in many flights. After 30 years in service from 1981 to 2011 and 135 flights, the shuttle was retired from service due to the cost of maintaining the shuttles, and the 3 remaining orbiters (the other two were destroyed in accidents) were prepared to be displayed in museums. Some spacecraft do not fit particularly well into any of

9350-463: The size of the rocket relative to the payload is similar to an Intercontinental Ballistic Missile (ICBM). Any intercontinental spaceflight has to surmount problems of heating during atmospheric re-entry that are nearly as large as those faced by orbital spaceflight. A minimal orbital spaceflight requires much higher velocities than a minimal sub-orbital flight, and so it is technologically much more challenging to achieve. To achieve orbital spaceflight,

9460-583: The sky and beyond. Space telescopes are distinct from Earth imaging satellites , which point toward Earth for satellite imaging , applied for weather analysis , espionage , and other types of information gathering . A lander is a type of spacecraft that makes a soft landing on the surface of an astronomical body other than Earth . Some landers, such as Philae and the Apollo Lunar Module , land entirely by using their fuel supply, however many landers (and landings of spacecraft on Earth ) use aerobraking , especially for more distant destinations. This involves

9570-431: The spacecraft to high enough speeds that it reaches orbit. Once in orbit, spacecraft are at high enough speeds that they fall around the Earth rather than fall back to the surface. Most spacecraft, and all crewed spacecraft, are designed to deorbit themselves or, in the case of uncrewed spacecraft in high-energy orbits, to boost themselves into graveyard orbits . Used upper stages or failed spacecraft, however, often lack

9680-415: The spacecraft using a fuel burn to change its trajectory so it will pass through a planet (or a moon's) atmosphere. Drag caused by the spacecraft hitting the atmosphere enables it to slow down without using fuel, however this generates very high temperatures and so adds a requirement for a heat shield of some sort. Space capsules are a type of spacecraft that can return from space at least once. They have

9790-640: The spacecraft, its occupants, and cargo can be recovered. In some cases, recovery has occurred before landing: while a spacecraft is still descending on its parachute, it can be snagged by a specially designed aircraft. This mid-air retrieval technique was used to recover the film canisters from the Corona spy satellites. Uncrewed spacecraft or robotic spacecraft are spacecraft without people on board. Uncrewed spacecraft may have varying levels of autonomy from human input, such as remote control , or remote guidance. They may also be autonomous , in which they have

9900-610: The tangential velocity around the Earth is as important as altitude. In order to perform a stable and lasting flight in space, the spacecraft must reach the minimal orbital speed required for a closed orbit . Interplanetary spaceflight is flight between planets within a single planetary system . In practice, the use of the term is confined to travel between the planets of our Solar System . Plans for future crewed interplanetary spaceflight missions often include final vehicle assembly in Earth orbit, such as NASA's Constellation program and Russia's Kliper / Parom tandem. New Horizons

10010-646: The technology for orbital launches independently from government agencies. The most prominent examples of such companies are SpaceX and Blue Origin . A German V-2 became the first spacecraft when it reached an altitude of 189 km in June 1944 in Peenemünde , Germany. Sputnik 1 was the first artificial satellite . It was launched into an elliptical low Earth orbit (LEO) by the Soviet Union on 4 October 1957. The launch ushered in new political, military, technological, and scientific developments; while

10120-411: The total amount of energy imparted by a rocket stage to its payload. This can be the energy imparted by a first stage of a launch vehicle to an upper stage plus payload, or by an upper stage or spacecraft kick motor to a spacecraft . In order to reach a space station , a spacecraft would have to arrive at the same orbit and approach to a very close distance (e.g. within visual contact). This

10230-412: The use of novel technologies for orbit raising because they operate in orbits that would ordinarily decay too soon to be economically useful. A low Earth orbit requires the lowest amount of energy for satellite placement. It provides high bandwidth and low communication latency . Satellites and space stations in LEO are more accessible for crew and servicing. Since it requires less energy to place

10340-460: The use of some new, advanced method of propulsion . Dynamic soaring as a way to travel across interstellar space has been proposed as well. Intergalactic travel involves spaceflight between galaxies, and is considered much more technologically demanding than even interstellar travel and, by current engineering terms, is considered science fiction . However, theoretically speaking, there is nothing to conclusively indicate that intergalactic travel

10450-413: The vehicle is to land safely without vaporizing in the atmosphere. Typically this process requires special methods to protect against aerodynamic heating . The theory behind reentry was developed by Harry Julian Allen . Based on this theory, reentry vehicles present blunt shapes to the atmosphere for reentry. Blunt shapes mean that less than 1% of the kinetic energy ends up as heat reaching the vehicle, and

10560-460: The vehicle's mass and increase its delta-v . Launch systems are used to carry a payload from Earth's surface into outer space. Most current spaceflight uses multi-stage expendable launch systems to reach space. The first reusable spacecraft, the X-15 , was air-launched on a suborbital trajectory on 19 July 1963. The first partially reusable orbital spacecraft, the Space Shuttle , was launched by

10670-420: The vicinity of Jupiter are too hostile for human survival. Outer planets such as Saturn , Uranus , and Neptune are too distant to reach with current crewed spaceflight technology, so telerobotic probes are the only way to explore them. Telerobotics also allows exploration of regions that are vulnerable to contamination by Earth micro-organisms since spacecraft can be sterilized. Humans can not be sterilized in

10780-453: Was Sputnik , launched October 4, 1957 to orbit the Earth. Nearly all satellites , landers and rovers are robotic spacecraft. Not every uncrewed spacecraft is a robotic spacecraft; for example, a reflector ball is a non-robotic uncrewed spacecraft. Space missions where other animals but no humans are on-board are called uncrewed missions. The first human spaceflight was Vostok 1 on April 12, 1961, on which cosmonaut Yuri Gagarin of

10890-502: Was Vostok 1 , which carried Soviet cosmonaut Yuri Gagarin into space in 1961, and completed a full Earth orbit. There were five other crewed missions which used a Vostok spacecraft . The second crewed spacecraft was named Freedom 7 , and it performed a sub-orbital spaceflight in 1961 carrying American astronaut Alan Shepard to an altitude of just over 187 kilometers (116 mi). There were five other crewed missions using Mercury spacecraft . Other Soviet crewed spacecraft include

11000-480: Was NASA's first space probe intended to reach the Moon. A partial failure caused it to instead follow a suborbital trajectory to an altitude of 113,854 kilometers (70,746 mi) before reentering the Earth's atmosphere 43 hours after launch. The most generally recognized boundary of space is the Kármán line 100 km (62 mi) above sea level. (NASA alternatively defines an astronaut as someone who has flown more than 80 km (50 mi) above sea level.) It

11110-612: Was a spaceplane that was launched at NASA’s Kennedy Space Centre and landed mainly at the Shuttle Landing Facility , which is part of Kennedy Space Centre. A second launch site, Vandenberg Space Launch Complex 6 in California , was revamped so it could be used to launch the shuttles, but it was never used. The launch system could lift about 29 tonnes (64,000 lb) into an eastward Low Earth Orbit . Each orbiter weighed roughly 78 tonnes (172,000 lb), however

11220-457: Was due to expensive refurbishment costs and the external tank being expended. Once a landing had occurred, the SRBs and many parts of the orbiter had to be disassembled for inspection, which was long and arduous. Furthermore, the RS-25 engines had to be replaced every few flights. Each of the heat shielding tiles had to go in one specific area on the orbiter, increasing complexity more. Adding to this,

11330-687: Was launched during the International Geophysical Year from Site No.1/5 , at the 5th Tyuratam range, in Kazakh SSR (now at the Baikonur Cosmodrome ). The satellite travelled at 29,000 kilometres per hour (18,000 mph), taking 96.2 minutes to complete an orbit, and emitted radio signals at 20.005 and 40.002  MHz While Sputnik 1 was the first spacecraft to orbit the Earth, other human-made objects had previously reached an altitude of 100 km, which

11440-606: Was manually operated, though an autonomous landing system was added while the shuttle was still on service. It had an in orbit maneouvreing system known as the Orbital Manoeuvring System, which used the hypergolic propellants monomethylhydrazine (MMH) and dinitrogen tetroxide , which was used for orbital insertion, changes to orbits and the deorbit burn. Though the shuttle’s goals were to drastically decrease launch costs, it did not do so, ending up being much more expensive than similar expendable launchers. This

11550-439: Was planned to begin reusable private spaceflight carrying paying passengers in 2014, but was delayed after the crash of VSS Enterprise . The Space Shuttle is a retired reusable Low Earth Orbital launch system. It consisted of two reusable Solid Rocket Boosters that landed by parachute, were recovered at sea, and were the most powerful rocket motors ever made until they were superseded by those of NASA’s SLS rocket, with

11660-663: Was published by Scottish astronomer and mathematician William Leitch , in an 1861 essay "A Journey Through Space". More well-known is Konstantin Tsiolkovsky 's work, " Исследование мировых пространств реактивными приборами " ( The Exploration of Cosmic Space by Means of Reaction Devices ), published in 1903. In his work, Tsiolkovsky describes the fundamental rocket equation: Δ v = v e ln ⁡ m 0 m f {\displaystyle \Delta v=v_{e}\ln {\frac {m_{0}}{m_{f}}}} Where: This equation, known as

11770-403: Was taking a longer route that allowed it to visit Uranus and Neptune, whereas Voyager 1 did not visit Uranus or Neptune, instead choosing to fly past Saturn’s satellite Titan . As of August 2023, Voyager 1 has passed 160 astronomical units , which means it is over 160 times farther from the Sun than Earth is. This makes it the farthest spacecraft from the Sun. Voyager 2 is 134 AU away from

11880-530: Was the Buran -class shuttle , launched by the USSR on November 15, 1988, although it made only one flight and this was uncrewed. This spaceplane was designed for a crew and strongly resembled the U.S. Space Shuttle, although its drop-off boosters used liquid propellants and its main engines were located at the base of what would be the external tank in the American Shuttle. Lack of funding, complicated by

11990-625: Was the Columbia , followed by the Challenger , Discovery , Atlantis , and Endeavour . The Endeavour was built to replace the Challenger , which was lost in January 1986. The Columbia broke up during reentry in February 2003. Low Earth orbit A low Earth orbit ( LEO ) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of

12100-474: Was the Space Shuttle orbiter . The first orbiter to fly in space, the Space Shuttle Columbia , was launched by the USA on the 20th anniversary of Yuri Gagarin 's flight, on April 12, 1981. During the Shuttle era, six orbiters were built, all of which have flown in the atmosphere and five of which have flown in space. Enterprise was used only for approach and landing tests, launching from

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