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75-424: Spaceflights include the launches of Earth observation and telecommunications satellites, interplanetary missions , 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

150-421: 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

225-496: 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

300-511: 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

375-491: A converging-diverging nozzle in his steam jet pumps by 1878 after using convergent nozzles but these nozzles remained a company secret. Later, Swedish engineer Gustaf de Laval applied his own converging diverging nozzle design for use on his impulse turbine in the year 1888. Laval's convergent-divergent nozzle was first applied in a rocket engine by Robert Goddard . Most modern rocket engines that employ hot gas combustion use de Laval nozzles. Its operation relies on

450-443: 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,

525-414: 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,

600-451: 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

675-594: 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

750-409: A nozzle, it is moving at subsonic velocities. As the cross-sectional area contracts, the gas is forced to accelerate until the axial velocity becomes sonic at the nozzle throat, where the cross-sectional area is the smallest. From there the throat the cross-sectional area then increases, allowing the gas to expand and the axial velocity to become progressively more supersonic . The linear velocity of

825-611: 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

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900-440: A satellite to hover over a constant spot on the earth since the orbital period at this altitude is 24 hours. This allows uninterrupted coverage of more than 1/3 of the Earth per satellite, so three satellites, spaced 120° apart, can cover the whole Earth. This type of orbit is mainly used for meteorological satellites . Herman Potočnik explored the idea of using orbiting spacecraft for detailed peaceful and military observation of

975-531: Is a type of satellite that is primarily used to monitor the weather and climate of the Earth . These meteorological satellites, however, see more than clouds and cloud systems. City lights, fires , effects of pollution , auroras , sand and dust storms , snow cover, ice mapping, boundaries of ocean currents , energy flows, etc., are other types of environmental information collected using weather satellites. Weather satellite images helped in monitoring

1050-403: Is at its minimum, the gas velocity locally becomes sonic (Mach number = 1.0), a condition called choked flow . As the nozzle cross-sectional area increases, the gas begins to expand, and the flow increases to supersonic velocities, where a sound wave will not propagate backward through the gas as viewed in the frame of reference of the nozzle ( Mach number > 1.0). As the gas exits the throat,

1125-519: Is classified in accordance with ITU Radio Regulations (article 1) as follows: Fixed service (article 1.20) The allocation of radio frequencies is provided according to Article 5 of the ITU Radio Regulations (edition 2012). In order to improve harmonisation in spectrum utilisation, the majority of service-allocations stipulated in this document were incorporated in national Tables of Frequency Allocations and Utilisations which

1200-417: Is consistent with above typical values. Technical literature often interchanges without note the universal gas law constant R , which applies to any ideal gas , with the gas law constant R s , which applies only to a specific individual gas of molar mass M . The relationship between the two constants is R s = R/M . In accordance with conservation of mass the mass flow rate of the gas throughout

1275-484: 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

1350-887: 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

1425-582: 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

1500-541: 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

1575-646: 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

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1650-455: 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

1725-649: 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

1800-402: Is with-in the responsibility of the appropriate national administration. The allocation might be primary, secondary, exclusive, and shared. However, military usage, in bands where there is civil usage, will be in accordance with the ITU Radio Regulations. De Laval nozzle A de Laval nozzle (or convergent-divergent nozzle , CD nozzle or con-di nozzle ) is a tube which is pinched in

1875-579: The Cold War prompted the rapid development of Satellite launch systems and camera technology capable of sufficient Earth observation to garner intelligence on enemy military infrastructure and evaluate nuclear posture. Following the U-2 incident in 1960, which highlighted the risks of aerial spying, the U.S. accelerated surveillance satellite programs like CORONA . Satellites largely replaced aircraft overflights for surveillance after 1960. A weather satellite

1950-536: The MetOp spacecraft of EUMETSAT are all operated at altitudes of about 800 km (500 mi). The Proba-1 , Proba-2 and SMOS spacecraft of European Space Agency are observing the Earth from an altitude of about 700 km (430 mi). The Earth observation satellites of UAE, DubaiSat-1 & DubaiSat-2 are also placed in Low Earth orbits (LEO) orbits and providing satellite imagery of various parts of

2025-484: 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

2100-460: 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

2175-457: 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

2250-403: 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,

2325-531: The Earth. To get global coverage with a low orbit, a polar orbit is used. A low orbit will have an orbital period of roughly 100 minutes and the Earth will rotate around its polar axis about 25° between successive orbits. The ground track moves towards the west 25° each orbit, allowing a different section of the globe to be scanned with each orbit. Most are in Sun-synchronous orbits . A geostationary orbit , at 36,000 km (22,000 mi), allows

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2400-697: 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

2475-458: 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 ,

2550-539: 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

2625-423: 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

2700-514: 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

2775-537: 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 ,

2850-644: 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

2925-432: 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

3000-458: The above equation, assume that the propellant combustion gases are: at an absolute pressure entering the nozzle p  = 7.0 MPa and exit the rocket exhaust at an absolute pressure p e = 0.1 MPa; at an absolute temperature of T = 3500 K; with an isentropic expansion factor γ = 1.22 and a molar mass M  = 22 kg/kmol. Using those values in the above equation yields an exhaust velocity v e = 2802 m/s, or 2.80 km/s, which

3075-583: The current vegetation state to its long term average. For example, the 2002 oil spill off the northwest coast of Spain was watched carefully by the European ENVISAT , which, though not a weather satellite, flies an instrument (ASAR) which can see changes in the sea surface. Anthropogenic emissions can be monitored by evaluating data of tropospheric NO 2 and SO 2 . These types of satellites are almost always in Sun-synchronous and "frozen" orbits. A Sun-synchronous orbit passes over each spot on

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3150-413: The different properties of gases flowing at subsonic , sonic , and supersonic speeds. The speed of a subsonic flow of gas will increase if the pipe carrying it narrows because the mass flow rate is constant. The gas flow through a de Laval nozzle is isentropic (gas entropy is nearly constant). In a subsonic flow, sound will propagate through the gas. At the "throat", where the cross-sectional area

3225-495: The discovery of the Earth's Van Allen radiation belts . The TIROS-1 spacecraft, launched on April 1, 1960, as part of NASA's Television Infrared Observation Satellite (TIROS) program, sent back the first television footage of weather patterns to be taken from space. In 2008, more than 150 Earth observation satellites were in orbit, recording data with both passive and active sensors and acquiring more than 10 terabits of data daily. By 2021, that total had grown to over 950, with

3300-400: The exiting exhaust gases can be calculated using the following equation: Some typical values of the exhaust gas velocity v e for rocket engines burning various propellants are: As a note of interest, v e is sometimes referred to as the ideal exhaust gas velocity because it is based on the assumption that the exhaust gas behaves as an ideal gas. As an example calculation using

3375-411: The ground at the same time of day, so that observations from each pass can be more easily compared, since the Sun is in the same spot in each observation. A "frozen" orbit is the closest possible orbit to a circular orbit that is undisturbed by the oblateness of the Earth , gravitational attraction from the Sun and Moon, solar radiation pressure , and air drag . Terrain can be mapped from space with

3450-494: The ground in his 1928 book, The Problem of Space Travel . He described how the special conditions of space could be useful for scientific experiments. The book described geostationary satellites (first put forward by Konstantin Tsiolkovsky ) and discussed communication between them and the ground using radio, but fell short of the idea of using satellites for mass broadcasting and as telecommunications relays. The onset of

3525-404: The increase in area allows it to undergo a Joule–Thomson expansion , wherein the gas expands at supersonic speeds from high to low pressure, pushing the velocity of the mass flow beyond sonic speed. When comparing the general geometric shape of the nozzle between the rocket and the jet engine, it looks different only at first glance, when in fact is about the same essential facts are noticeable on

3600-461: The largest number of satellites operated by US-based company Planet Labs . Most Earth observation satellites carry instruments that should be operated at a relatively low altitude. Most orbit at altitudes above 500 to 600 kilometers (310 to 370 mi). Lower orbits have significant air-drag , which makes frequent orbit reboost maneuvers necessary. The Earth observation satellites ERS-1, ERS-2 and Envisat of European Space Agency as well as

3675-465: The launch of the first artificial satellite, Sputnik 1 , by the Soviet Union on October 4, 1957. Sputnik 1 sent back radio signals, which scientists used to study the ionosphere . The United States Army Ballistic Missile Agency launched the first American satellite, Explorer 1 , for NASA's Jet Propulsion Laboratory on January 31, 1958. The information sent back from its radiation detector led to

3750-727: The middle, making a carefully balanced, asymmetric hourglass shape. It is used to accelerate a compressible fluid to supersonic speeds in the axial (thrust) direction, by converting the thermal energy of the flow into kinetic energy . De Laval nozzles are widely used in some types of steam turbines and rocket engine nozzles . It also sees use in supersonic jet engines . Similar flow properties have been applied to jet streams within astrophysics . Giovanni Battista Venturi designed converging-diverging tubes known as Venturi tubes for experiments on fluid pressure reduction effects when fluid flows through chokes ( Venturi effect ). German engineer and inventor Ernst Körting supposedly switched to

3825-554: The mission is orbital , the spacecraft usually separates the first stage and ignites the second stage , which propels 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

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3900-409: 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

3975-406: 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

4050-679: The nozzle is the same regardless of the cross-sectional area. m ˙ = A p t T t ⋅ γ M R ⋅ M a ⋅ ( 1 + γ − 1 2 M a 2 ) − γ + 1 2 ( γ − 1 ) {\displaystyle {\dot {m}}={\frac {Ap_{t}}{\sqrt {T_{t}}}}\cdot {\sqrt {\frac {\gamma M}{R}}}\cdot \mathrm {Ma} \cdot (1+{\frac {\gamma -1}{2}}\mathrm {Ma} ^{2})^{-{\frac {\gamma +1}{2(\gamma -1)}}}} When

4125-410: The nozzle, forming an unstable jet that may "flop" around within the nozzle, producing a lateral thrust and possibly damaging it. In practice, ambient pressure must be no higher than roughly 2–3 times the pressure in the supersonic gas at the exit for supersonic flow to leave the nozzle. The analysis of gas flow through de Laval nozzles involves a number of concepts and assumptions: As the gas enters

4200-439: The nozzle, where the flow accelerates. A de Laval nozzle will choke at the throat only if the pressure and mass flow through the nozzle is sufficient to reach sonic speeds; otherwise no supersonic flow is achieved, and it will act as a Venturi tube . This requires the entry pressure to the nozzle to be significantly above ambient at all times (equivalently, the stagnation pressure of the jet must be above ambient). In addition,

4275-402: 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

4350-399: 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

4425-408: The pressure of the gas at the exit of the expansion portion of the exhaust of a nozzle must not be too low. Because pressure cannot travel upstream through the supersonic flow, the exit pressure can be significantly below the ambient pressure into which it exhausts, but if it is too far below ambient, then the flow will cease to be supersonic , or the flow will separate within the expansion portion of

4500-464: 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,

4575-401: The same geometric cross-sections – that the combustion chamber in the jet engine must have the same "throat" (narrowing) in the direction of the outlet of the gas jet, so that the turbine wheel of the first stage of the jet turbine is always positioned immediately behind that narrowing, while any on the further stages of the turbine are located at the larger outlet cross-section of

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4650-463: 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,

4725-640: 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

4800-610: 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

4875-603: The throat is at sonic speed Ma = 1 where the equation simplifies to: m ˙ = A p t T t ⋅ γ M R ⋅ ( γ + 1 2 ) − γ + 1 2 ( γ − 1 ) {\displaystyle {\dot {m}}={\frac {Ap_{t}}{\sqrt {T_{t}}}}\cdot {\sqrt {\frac {\gamma M}{R}}}\cdot ({\frac {\gamma +1}{2}})^{-{\frac {\gamma +1}{2(\gamma -1)}}}} By Newton's third law of motion

4950-409: 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

5025-740: The use of satellites, such as Radarsat-1 and TerraSAR-X . According to the International Telecommunication Union (ITU), Earth exploration-satellite service (also: Earth exploration-satellite radiocommunication service ) is – according to Article 1.51 of the ITU Radio Regulations (RR) – defined as: A radiocommunication service between earth stations and one or more space stations , which may include links between space stations, in which: This service may also include feeder links necessary for its operation. This radiocommunication service

5100-458: 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

5175-413: 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

5250-460: 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

5325-478: The volcanic ash cloud from Mount St. Helens and activity from other volcanoes such as Mount Etna . Smoke from fires in the western United States such as Colorado and Utah have also been monitored. Other environmental satellites can assist environmental monitoring by detecting changes in the Earth's vegetation, atmospheric trace gas content, sea state, ocean color, and ice fields. By monitoring vegetation changes over time, droughts can be monitored by comparing

5400-453: 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

5475-480: 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

5550-602: 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

5625-1213: 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. Earth observation satellite An Earth observation satellite or Earth remote sensing satellite is a satellite used or designed for Earth observation (EO) from orbit , including spy satellites and similar ones intended for non-military uses such as environmental monitoring , meteorology , cartography and others. The most common type are Earth imaging satellites , that take satellite images , analogous to aerial photographs ; some EO satellites may perform remote sensing without forming pictures, such as in GNSS radio occultation . The first occurrence of satellite remote sensing can be dated to

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