Spaceflight can be achieved conventionally viamultistage rockets, which provide the thrust to overcome the force of gravity and propel spacecraft ontosuborbital trajectories. If the mission isorbital, the spacecraft usually separates thefirst stage and ignites thesecond 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 todeorbit themselves or, in the case of uncrewed spacecraft in high-energy orbits, to boost themselves intograveyard orbits. Used upper stages or failed spacecraft, however, often lack the ability to deorbit themselves. This becomes a major issue when large numbers of uncontrollable spacecraft exist in frequently used orbits, increasing the risk ofdebris 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 is known asKessler syndrome.
There are several terms that refer to a flight into or throughouter space.
Aspace mission refers to a spaceflight intended to achieve an objective. Objectives for space missions may includespace 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 includehuman spaceflight andcargo spacecraft flight.
The first theoretical proposal of space travel usingrockets was published by Scottish astronomer and mathematicianWilliam Leitch, in an 1861 essay "A Journey Through Space".[1] More well-known isKonstantin 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:
Where:
() is the change in the rocket's velocity
() is the exhaust velocity
() and () are the initial and final masses of the rocket
This equation, known as theTsiolkovsky rocket equation, can be used to find the total, 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 ofRobert H. Goddard's publication in 1919 of his paperA Method of Reaching Extreme Altitudes. His application of thede Laval nozzle toliquid-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 thefirst World War but his plans were foiled by theNovember 11, 1918 armistice with Germany. After choosing to work with private financial support, he was the first to launch a liquid-fueled rocket on March 16, 1926.
DuringWorld War II, the first guided rocket, theV-2, was developed and employed as a weapon byNazi 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.[2] At the end of World War II, most of the V-2 rocket team, including its head,Wernher von Braun, surrendered to the United States, and were expatriated to work on American missiles at what became theArmy Ballistic Missile Agency, producing missiles such asJuno I andAtlas. TheSoviet 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 U.S., after the launch of Sputnik and two embarrassing failures ofVanguard rockets, launchedExplorer 1 on February 1, 1958. Three years later, the USSR launched Vostok 1, carrying cosmonautYuri Gagarin into orbit. The US responded with the suborbital launch ofAlan Shepard on May 5, 1961, and the orbital launch ofJohn Glenn on February 20, 1962. These events were followed by a pledge from U.S.President John F. Kennedy togo to the moon and the creation of theGemini andApollo programs. After successfully performing a rendezvous and docking and anEVA, the Gemini program ended just before theApollo 1 tragedy. Following multiple uncrewed test flights of theSaturn 1B and theSaturn V, the U.S. launched the crewedApollo 7 mission intolow Earth orbit. Shortly after its successful completion, the U.S. launchedApollo 8 (first mission to orbit the Moon),Apollo 9 (first Apollo mission to launch with both theCSM and theLEM) andApollo 10 (first mission to nearly land on 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 the Moon and developed continuous crewedhuman presence in space with a series ofspace stations, ranging from theSalyut program to theInternational Space Station.
Rockets are the only means currently capable of reaching orbit or beyond. Othernon-rocket spacelaunch technologies have yet to be built, or remain short of orbital speeds. Arocket launch for a spaceflight usually starts from aspaceport (cosmodrome), which may be equipped with launch complexes andlaunch 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 certainlaunch windows. These windows depend upon 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.
Alaunch pad is a fixed structure designed to dispatch airborne vehicles. It generally consists of 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. TheSpace ShuttleColumbia, onSTS-1, weighed 2030 metric tons (4,480,000 lb) at takeoff.
The most commonly used definition ofouter space is everything beyond theKármán line, which is 100 kilometers (62 mi) above 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 andhigh-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, 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 thespace elevator, andmomentum exchange tethers likerotovators orskyhooks require new materials much stronger than any currently known. Electromagnetic launchers such aslaunch loops might be feasible with current technology. Other ideas include rocket-assisted aircraft/spaceplanes such asReaction Engines Skylon (currently in early stage development),scramjet powered spaceplanes, andRBCC powered spaceplanes. Gun launch has been proposed for cargo.
On some missions beyondLEO (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 a "time buffer" and substantially widened the allowablelaunch 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.[3]
Launched in 1959,Luna 1 was the first known artificial object to achieve escape velocity from the Earth(replica pictured).[4]
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 the Moon and other planets generally use direct injection to maximize performance by limiting the boil off ofcryogenic 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 is more fuel-efficient for a craft to burn its fuel as close as possible to itsperiapsis (lowest point); seeOberth effect.[5]
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. Anorbital maneuvering system may be needed to maintain or change orbits.
The term "transfer energy" means the total amount ofenergy imparted by a rocket stage to its payload. This can be the energy imparted by afirst stage of alaunch vehicle to an upper stage plus payload, or by an upper stage or spacecraftkick motor to aspacecraft.[6][7]
In order to reach aspace station, a spacecraft would have to arrive at the sameorbit and approach to a very close distance (e.g. within visual contact). This is done by a set of orbital maneuvers calledspace 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,[8][9][10][11] while berthing refers to mating operations where an inactive vehicle is placed into the mating interface of another space vehicle by using arobotic arm.[8][10][11]
Vehicles in orbit have large amounts of kinetic energy. This energy must be discarded if the vehicle is to land safely without vaporizing in the atmosphere. Typically this process requires special methods to protect againstaerodynamic heating. The theory behind reentry was developed byHarry 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 the remainder heats the atmosphere.
TheMercury,Gemini, andApollo capsulessplashed down in the sea. These capsules were designed to land at relatively low speeds with the help of a parachute. Soviet/Russian capsules forSoyuz make use of a big parachute and braking rockets to touch down on land.Spaceplanes like theSpace Shuttle land like aglider.
After a successful landing, 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. Thismid-air retrieval technique was used to recover the film canisters from theCorona spy satellites.
Uncrewed spacecraft or robotic spacecraft arespacecraft withoutpeople on board. Uncrewed spacecraft may have varying levels of autonomy from human input, such asremote control, or remote guidance. They may also beautonomous, in which they have 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 orspace observatory.
Many space missions are more suited totelerobotic rather thancrewed operation, due to lower cost and risk factors. In addition, some planetary destinations such asVenus or the vicinity ofJupiter are too hostile for human survival, given current technology. Outer planets such asSaturn,Uranus, andNeptune 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 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 wasSputnik, launched October 4, 1957 to orbit the Earth. Nearly allsatellites,landers androvers 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 otheranimals but no humans are on-board are called uncrewed missions.
Many habitable spacecraft also have varying levels of robotic features. For example, the space stationsSalyut 7 andMir, and theInternational Space Station moduleZarya, were capable of remote guided station-keeping and docking maneuvers with both resupply craft and new modules.Uncrewed resupply spacecraft are increasingly used for crewedspace stations.
The first human spaceflight wasVostok 1 on April 12, 1961, on whichcosmonautYuri Gagarin of theUSSR made one orbit around the Earth. In official Soviet documents, there is no mention of the fact that Gagarin parachuted the final seven miles.[12] As of 2020, the only spacecraft regularly used for human spaceflight areSoyuz,Shenzhou, andCrew Dragon. The U.S.Space Shuttle fleet operated from April 1981 until July 2011.SpaceShipOne has conducted three human suborbital space flights.
On asub-orbital spaceflight the spacecraft reaches space and then returns to the atmosphere after following a (primarily) ballistic trajectory. This is usually because of insufficientspecific 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 was NASA's firstspace 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 theKármán 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 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 the GoFast rocket on a suborbital flight, the first amateur spaceflight. On June 21, 2004,SpaceShipOne was used for the firstprivately fundedhuman spaceflight.
Point-to-point, or Earth to Earth transportation, is a category ofsub-orbital spaceflight in which a spacecraft provides rapid transport between two terrestrial locations.[13] A conventional airline route betweenLondon andSydney, a flight that normally lastsover twenty hours, could be traversed in less than one hour.[14] While no company offers this type of transportation today,SpaceX has revealed plans to do so as early as the 2020s usingStarship. 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.[15] If rockets are used, 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 minimalorbital 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, 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 minimalorbital speed required for aclosed orbit.
Interplanetary spaceflight is flight between planets within a singleplanetary system. In practice, the use of the term is confined to travel between the planets of ourSolar System. Plans for future crewed interplanetary spaceflight missions often include final vehicle assembly in Earth orbit, such as NASA'sConstellation program and Russia'sKliper/Parom tandem.
New Horizons is the fifth spacecraft put on an escape trajectory leaving theSolar System.Voyager 1,Voyager 2,Pioneer 10,Pioneer 11 are the earlier ones. The one farthest from the Sun isVoyager 1, which is more than 100AU distant and is moving at 3.6 AU per year.[16] In comparison,Proxima Centauri, the closest star other than the Sun, is 267,000 AU distant. It will takeVoyager 1 over 74,000 years to reach this distance. Vehicle designs using other techniques, such asnuclear pulse propulsion are likely to be able to reach the nearest star significantly faster. Another possibility that could allow for human interstellar spaceflight is to make use oftime 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 the use of some new, advanced method ofpropulsion.Dynamic soaring as a way to travel across interstellar space has been proposed as well.[17][18]
Intergalactic travel involves spaceflight between galaxies, and is considered much more technologically demanding than even interstellar travel and, by current engineering terms, is consideredscience fiction. However, theoretically speaking, there is nothing to conclusively indicate that intergalactic travel is impossible. To date several academics have studied intergalactic travel in a serious manner.[19][20][21]
Spacecraft are vehicles designed to operate in space.
The first 'true spacecraft' is sometimes said to beApollo Lunar Module,[22] 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 userockets forpropulsion, but other propulsion techniques such asion drives are becoming more common, particularly for uncrewed vehicles, and this can significantly reduce the vehicle's mass and increase itsdelta-v.
The first reusable spacecraft, theX-15, was air-launched on a suborbital trajectory on 19 July 1963. The first partially reusable orbital spacecraft, theSpace Shuttle, was launched by the USA on the 20th anniversary ofYuri 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. TheEnterprise was used only for approach and landing tests, launching from the back of aBoeing 747 and gliding to deadstick landings atEdwards AFB, California. The first Space Shuttle to fly into space was theColumbia, followed by theChallenger,Discovery,Atlantis, andEndeavour. TheEndeavour was built to replace theChallenger, which waslost in January 1986. TheColumbiabroke up during reentry in February 2003.
The first automatic partially reusable spacecraft was theBuran (Snowstorm), launched by the USSR on 15 November 1988, although it made only one flight. Thisspaceplane was designed for a crew and strongly resembled the US 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 the dissolution of the USSR, prevented any further flights of Buran.
The Space Shuttle was retired in 2011 due mainly to its old age. The Shuttle's human transport role is to be replaced by theSpaceX Dragon 2 andCST-100 in the 2020s. The Shuttle's heavy cargo transport role is now done by commercial launch vehicles.
SpaceX achieved the first vertical soft landing of a reusable orbital rocket stage on December 21, 2015, after delivering 11Orbcomm OG-2 commercial satellites intolow Earth orbit.[24]
The first Falcon 9 reflight occurred on 30 March 2017.[25] SpaceX now routinely recovers and reusestheir first stages and fairings.[26] SpaceX is now developing a fully reusable super heavy lift rocket known asStarship, with the goal of drastically reducing the price of space exploration.[27] As of February 2025, two Super Heavy boosters, the first stage of Starship, have been recovered.[28][29]
All launch vehicles contain a huge amount of energy that is needed for some part of it to reach orbit. There is therefore some risk that this energy can be released prematurely and suddenly, with significant effects. When aDelta II rocket exploded 13 seconds after launch on January 17, 1997, there were reports of store windows 10 miles (16 km) away being broken by the blast.[30]
Space is a fairly predictable environment, but there are still risks of accidental depressurization and the potential failure of equipment, some of which may be very newly developed.
Astronauts on theISS in weightless conditions.Michael Foale can be seen exercising in the foreground.
In a microgravity environment such as that provided by a spacecraft in orbit around the Earth, humans experience a sense of "weightlessness." Short-term exposure to microgravity causesspace adaptation syndrome, a self-limiting nausea caused by derangement of thevestibular system. Long-term exposure causes multiple health issues. The most significant is bone loss, some of which is permanent, but microgravity also leads to significantdeconditioning of muscular and cardiovascular tissues.
In human spaceflight, thelife support system is a group of devices that allow a human being to survive in outer space.NASA often uses the phrase Environmental Control and Life Support System or the acronym ECLSS when describing these systems for itshuman spaceflight missions.[33] The life support system may supply:air,water andfood. It must also maintain the correct body temperature, an acceptable pressure on the body and deal with the body's waste products. Shielding against harmful external influences such as radiation and micro-meteorites may also be necessary. Components of the life support system arelife-critical, and are designed and constructed usingsafety engineering techniques.
Space weather is the concept of changing environmental conditions inouter space. It is distinct from the concept ofweather within aplanetary atmosphere, and deals with phenomena involving ambientplasma, magnetic fields,radiation and othermatter in space (generally close to Earth but also ininterplanetary, and occasionallyinterstellar medium). "Space weather describes the conditions in space that affect Earth and its technological systems. Our space weather is a consequence of the behavior of the Sun, the nature of Earth's magnetic field, and our location in the Solar System."[34]
Space weather exerts a profound influence in several areas related to space exploration and development. Changing geomagnetic conditions can induce changes in atmospheric density causing the rapid degradation of spacecraft altitude inLow Earth orbit. Geomagnetic storms due to increased solar activity can potentially blind sensors onboard spacecraft, or interfere with on-board electronics. An understanding of space environmental conditions is also important in designing shielding and life support systems for crewed spacecraft.
Exhaust pollution of rockets depends on the produced exhausts by the propellants reactions and the location of exhaustion. They mostly exhaustgreenhouse gases and sometimes toxic components. Particularly at higher levels of the atmosphere the potency of exhausted gases as greenhouse gases increases considerably.[35] Many solid rockets have chlorine in the form ofperchlorate or other chemicals, and this can cause temporary local holes in the ozone layer. Re-entering spacecraft generate nitrates which also can temporarily impact the ozone layer. Most rockets are made of metals that can have an environmental impact during their construction.While spaceflight altogether pollutes at a fraction of other human activities, it still does pollute heavily if calculated per passenger.[35]
In addition to the atmospheric effects there are effects on the near-Earth space environment. There is the possibility that orbit could become inaccessible for generations due to exponentially increasingspace debris caused byspalling of satellites and vehicles (Kessler syndrome). Many launched vehicles today are therefore designed to be re-entered after use.
Participation and representation of all humanity in spaceflight is an issue of internationalspace law ever since the first phase of space exploration.[36] Even though some rights of non-spacefaring countries have been secured, sharing of space for all humanity is still criticized asimperialist and lacking, understanding spaceflight as a resource.[36]
The dominating issue about access in most recent years has been the issue ofspace debris andspace sustainability, since established spacefaring countries endanger access to outer space with their orbital space polluting activity.[37]
This shows an extreme ultraviolet view of the Sun (the Apollo Telescope Mount SO82A Experiment) taken duringSkylab 3, with the Earth added for scale. On the right an image of the Sun shows a helium emissions, and there is an image on the left showing emissions from iron. One application for spaceflight is to take observation hindered or made more difficult by being on Earth's surface. Skylab included a massive crewed solar observatory that revolutionized solar science in the early 1970s using the Apollo-based space station in conjunction with crewed spaceflights to it.
Current and proposed applications for spaceflight include:
Most early spaceflight development was paid for by governments. However, today major launch markets such as communication satellites and satellite television are purely commercial, though many of the launchers were originally funded by governments.
Private spaceflight is a rapidly developing area: space flight that is not only paid for by corporations or even private individuals, but often provided byprivate spaceflight companies. These companies often assert that much of the previous high cost of access to space was caused by governmental inefficiencies they can avoid. This assertion can be supported by much lower published launch costs for private space launch vehicles such asFalcon 9 developed with private financing. Lower launch costs and excellent safety will be required for the applications such as space tourism and especially space colonization to become feasible for expansion.
Countries with independently developed human spaceflight programs
Countries that have operated at least one human spaceflight program, if not independently
Countries seeking to develop a human spaceflight program but also have developed or currently own a launch vehicle
Countries who operate a launch vehicle and a satellite but currently have no plans to develop a crewed space vehicle
Countries seeking to develop a launch vehicle
Countries who operate an orbiting satellite but do not own a launch vehicle or have plans to produce one
Countries who have a launch vehicle but do not currently operate a satellite
To bespacefaring is to be capable of and active in the operation ofspacecraft. It involves a knowledge of a variety of topics and development of specialised skills including:aeronautics;astronautics; programs to trainastronauts;space weather and forecasting; spacecraft operations; operation of various equipment; spacecraft design and construction; atmospheric takeoff and reentry;orbital mechanics (a.k.a. astrodynamics); communications; engines and rockets; execution of evolutions such as towing,microgravity construction, andspace docking; cargo handling equipment, dangerous cargos and cargo storage;spacewalking; dealing with emergencies;survival at space and first aid; fire fighting;life support. The degree of knowledge needed within these areas is dependent upon the nature of the work and the type of vessel employed. "Spacefaring" is analogous toseafaring.
There has never been a crewed mission outside theEarth–Moon system. However, the United States, Russia, China,European Space Agency (ESA) countries, and a few corporations and enterprises have plans in various stages to travel toMars (seeHuman mission to Mars).
Spacefaring entities can besovereign states, supranational entities, and privatecorporations. Spacefaring nations are those capable of independently building and launching craft into space.[38][39][40] A growing number of private entities have become or are becoming spacefaring.
TheUnited Nations Office for Outer Space Affairs (UNOOSA) has been the main multilateral body servicing international contact and exchange on space activity among spacefaring and non-spacefaring states.
The following nations or organizations have developed their own launch vehicles to launch uncrewed spacecraft into orbit either from their own territory or with foreign assistance (date of first launch in parentheses):[41]
★Launch vehicle fully or partially developed by another country
Also several countries, such as Canada, Italy, and Australia, had semi-independent spacefaring capability, launching locally-built satellites on foreign launchers. Canada had designed and built satellites (Alouette 1 and2) in 1962 and 1965 which were orbited using U.S. launch vehicles. Italy has designed and built several satellites, as well as pressurized modules for theInternational Space Station. Early Italian satellites were launched using vehicles provided by NASA, first fromWallops Flight Facility in 1964 and then from a spaceport in Kenya (San Marco Platform) between 1967 and 1988;[citation needed] Italy has led the development of theVega rocket programme within the European Space Agency since 1998.[46] TheUnited Kingdom abandoned its independent space launch program in 1972 in favour of co-operating with the European Launcher Development Organisation (ELDO) on launch technologies until 1974. Australia abandoned its launcher program shortly after the successful launch ofWRESAT, and became the only non-European member of ELDO.
Considering merely launching an object beyond theKármán line to be the minimum requirement of spacefaring,Germany, with theV-2 rocket, became the first spacefaring nation in 1944.[47] The following nations have only achievedsuborbital spaceflight capability by launching indigenousrockets ormissiles or both into suborbital space:
^abCook, John; Aksamentov, Valery; Hoffman, Thomas; Bruner, Wes (1 January 2011),ISS Interface Mechanisms and their Heritage(PDF), Houston, Texas: Boeing, retrieved31 March 2015 – via NASA,Docking is when one incoming spacecraft rendezvous with another spacecraft and flies a controlled collision trajectory in such a manner so as to align and mesh the interface mechanisms. The spacecraft docking mechanisms typically enter what is called soft capture, followed by a load attenuation phase, and then the hard docked position which establishes an air-tight structural connection between spacecraft. Berthing, by contrast, is when an incoming spacecraft is grappled by a robotic arm and its interface mechanism is placed close to the stationary interface mechanism. Then typically there is a capture process, coarse alignment and fine alignment, and then structural attachment.
^"International Docking Standardization"(PDF). NASA. 2009-03-17. p. 15. Retrieved2011-03-04.Docking: The joining or coming together of two separate free flying space vehicles
^abFehse, Wigbert (2003).Automated Rendezvous and Docking of Spacecraft. Cambridge, UK: Cambridge University Press.ISBN978-0521824927.
^ab"Advanced Docking/Berthing System – NASA Seal Workshop"(PDF). NASA. 2004-11-04. p. 15. Archived fromthe original(PDF) on September 22, 2011. Retrieved2011-03-04.Berthing refers to mating operations where an inactive module/vehicle is placed into the mating interface using a Remote Manipulator System-RMS. Docking refers to mating operations where an active vehicle flies into the mating interface under its own power.
^Vostok 1. Astronautix.com. Retrieved on 2011-10-05.
^Burghardt, Thomas (December 26, 2020)."Preparing for "Earth to Earth" space travel and a competition with supersonic airliners".NASA Spaceflight. RetrievedJanuary 29, 2021.The most prevalent concept for suborbital Earth to Earth transportation comes from none other than Elon Musk and SpaceX. Primarily designed for transporting large payloads to Mars for the purpose of colonization, the next generation Starship launch system offers a bonus capability for transporting large amounts of cargo around Earth.
^"Becoming a Multiplanetary Species"(PDF). 68th annual meeting of the International Astronautical Congress in Adelaide, Australia. SpaceX. 29 September 2017. Archived fromthe original(PDF) on 8 August 2018. Retrieved15 April 2018.
^Yap, Xiao-Shan; Heiberg, Jonas; Truffer, Bernhard (2023). "The emerging global socio-technical regime for tackling space debris: A discourse network analysis".Acta Astronautica.207:445–454.Bibcode:2023AcAau.207..445Y.doi:10.1016/j.actaastro.2023.01.016.
Sarah Scoles, "Why We'll Never Live in Space: The technological, biological, psychological and ethical challenges to leaving Earth", vol. 329, no. 3 (October 2023), pp. 22–29. "Perhaps the most significant concern isradiation, something that is manageable for today's astronauts flying in low-Earth orbit but would be a bigger deal for people traveling farther and for longer." (p. 25.) "On the edge of terrestrial frontiers, people were seeking, say, gold or more farmable land. In space, explorers can't be sure of the value proposition at their destination." (p. 27.) "Harmful extraterrestrialmicrobes could return with astronauts or equipment – a planetary-protection risk called backwardcontamination." (p. 28.)
Rebecca Boyle, "A Space Settler Walks into a Dome...: A very funny book about why living onMars is a terrible idea" (review ofKelly Weinersmith andZach Weinersmith,A City on Mars: Can We Settle Space, Should We Settle Space, and Have We Really Thought This Through?, Penguin Press, 2023),Scientific American, vol. 329, no. 4 (November 2023), p. 93.
Various conventions, treaties, agreements, memorandums, charters or declarations establishing and governing intergovernmental organisations or inter-agency bodies dealing with space affairs
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