Aerospace

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Aerospace

 

A view of the Earth's atmosphere with the Moon beyond

 

Aerospace is the human effort in science, engineering, and business to fly in the atmosphere of Earth (aeronautics) and surrounding space (astronautics). Aerospace organizations research, design, manufacture, operate, or maintain aircraft or spacecraft. Aerospace activity is very diverse, with a multitude of commercial, industrial and military applications. 

Aerospace is not the same as airspace, which is the physical air space directly above a location on the ground. The beginning of space and the ending of the air is considered as 100 km above the ground according to the physical explanation that the air pressure is too low for a lifting body to generate meaningful lift force without exceeding orbital velocity.

Overview

In most industrial countries, the aerospace industry is a cooperation of public and private industries. For example, several countries have a civilian space program funded by the government through tax collection, such as National Aeronautics and Space Administration in the United States, European Space Agency in Europe, the Canadian Space Agency in Canada, Indian Space Research Organisation in India, Japanese Aeronautics Exploration Agency in Japan,myanmar,RKA in Russia, China National Space Administration in China, SUPARCO in Pakistan, Iranian Space Agency in Iran, and Korea Aerospace Research Institute (KARI) in South Korea. 

Along with these public space programs, many companies produce technical tools and components such as spaceships and satellites. Some known companies involved in space programs include Boeing, Cobham, Airbus, SpaceX, Lockheed Martin, United Technologies, MacDonald Dettwiler and Northrop Grumman. These companies are also involved in other areas of aerospace such as the construction of aircraft. 

History

Modern aerospace began with Engineer George Cayley in 1799. Cayley proposed an aircraft with a "fixed wing and a horizontal and vertical tail," defining characteristics of the modern airplane.

The 19th century saw the creation of the Aeronautical Society of Great Britain (1866), the American Rocketry Society, and the Institute of Aeronautical Sciences, all of which made aeronautics a more serious scientific discipline. Airmen like Otto Lilienthal, who introduced cambered airfoils in 1891, used gliders to analyze aerodynamic forces. The Wright brothers were interested in Lilienthal's work and read several of his publications. They also found inspiration in Octave Chanute, an airman and the author of Progress in Flying Machines (1894). It was the preliminary work of Cayley, Lilienthal, Chanute, and other early aerospace engineers that brought about the first powered sustained flight at Kitty Hawk, North Carolina on December 17, 1903, by the Wright brothers.

War and science fiction inspired scientists and engineers like Konstantin Tsiolkovsky and Wernher von Braun to achieve flight beyond the atmosphere. World War II inspired Wernher von Braun to create the V1 and V2 rockets.

The launch of Sputnik 1 in October 1957 started the Space Age, and on July 20, 1969 Apollo 11 achieved the first manned moon landing. In April 1981, the Space Shuttle Columbia launched, the start of regular manned access to orbital space. A sustained human presence in orbital space started with "Mir" in 1986 and is continued by the "International Space Station". Space commercialization and space tourism are more recent features of aerospace.

Manufacturing

Aerospace manufacturing is a high-technology industry that produces "aircraft, guided missiles, space vehicles, aircraft engines, propulsion units, and related parts". Most of the industry is geared toward governmental work. For each original equipment manufacturer (OEM), the US government has assigned a Commercial and Government Entity (CAGE) code. These codes help to identify each manufacturer, repair facilities, and other critical aftermarket vendors in the aerospace industry.

In the United States, the Department of Defense and the National Aeronautics and Space Administration (NASA) are the two largest consumers of aerospace technology and products. Others include the very large airline industry. The aerospace industry employed 472,000 wage and salary workers in 2006. Most of those jobs were in Washington state and in California, with Missouri, New York and Texas also being important. The leading aerospace manufacturers in the U.S. are Boeing, United Technologies Corporation, SpaceX, Northrop Grumman and Lockheed Martin. These manufacturers are facing an increasing labor shortage as skilled U.S. workers age and retire. Apprenticeship programs such as the Aerospace Joint Apprenticeship Council (AJAC) work in collaboration with Washington state aerospace employers and community colleges to train new manufacturing employees to keep the industry supplied. 

Important locations of the civilian aerospace industry worldwide include Washington state (Boeing), California (Boeing, Lockheed Martin, etc.); Montreal, Quebec, Canada (Bombardier, Pratt & Whitney Canada); Toulouse, France (Airbus/EADS); Hamburg, Germany (Airbus/EADS); and São José dos Campos, Brazil (Embraer), Querétaro, Mexico (Bombardier Aerospace, General Electric Aviation) and Mexicali, Mexico (United Technologies Corporation, Gulfstream Aerospace).

In the European Union, aerospace companies such as EADS, BAE Systems, Thales, Dassault, Saab AB and Leonardo S.p.A. (formerly Finmeccnica) account for a large share of the global aerospace industry and research effort, with the European Space Agency as one of the largest consumers of aerospace technology and products. 

In India, Bangalore is a major center of the aerospace industry, where Hindustan Aeronautics Limited, the National Aerospace Laboratories and the Indian Space Research Organisation are headquartered. The Indian Space Research Organisation (ISRO) launched India's first Moon orbiter, Chandrayaan-1, in October 2008.

In Russia, large aerospace companies like Oboronprom and the United Aircraft Building Corporation (encompassing Mikoyan, Sukhoi, Ilyushin, Tupolev, Yakovlev, and Irkut which includes Beriev) are among the major global players in this industry. The historic Soviet Union was also the home of a major aerospace industry.

The United Kingdom formerly attempted to maintain its own large aerospace industry, making its own airliners and warplanes, but it has largely turned its lot over to cooperative efforts with continental companies, and it has turned into a large import customer, too, from countries such as the United States. However, the UK has a very active aerospace sector, including the second largest defence contractor in the world, BAE Systems, supplying fully assembled aircraft, aircraft components, sub-assemblies and sub-systems to other manufacturers, both in Europe and all over the world.

Canada has formerly manufactured some of its own designs for jet warplanes, etc. (e.g. the CF-100 fighter), but for some decades, it has relied on imports from the United States and Europe to fill these needs. However Canada still manufactures some military aircraft although they are generally not combat capable. Another notable example was the late 1950s development of the Avro Canada CF-105 Arrow, a supersonic fighter-interceptor that was cancelled in 1959 a highly controversial decision.

France has continued to make its own warplanes for its air force and navy, and Sweden continues to make its own warplanes for the Swedish Air Force—especially in support of its position as a neutral country. (See Saab AB.) Other European countries either team up in making fighters (such as the Panavia Tornado and the Eurofighter Typhoon), or else to import them from the United States.

Pakistan has a developing aerospace engineering industry. The National Engineering and Scientific Commission, Khan Research Laboratories and Pakistan Aeronautical Complex are among the premier organizations involved in research and development in this sector. Pakistan has the capability of designing and manufacturing guided rockets, missiles and space vehicles. The city of Kamra is home to the Pakistan Aeronautical Complex which contains several factories. This facility is responsible for manufacturing the MFI-17, MFI-395, K-8 and JF-17 Thunder aircraft. Pakistan also has the capability to design and manufacture both armed and unarmed unmanned aerial vehicles.

In the People's Republic of China, Beijing, Xi'an, Chengdu, Shanghai, Shenyang and Nanchang are major research and manufacture centers of the aerospace industry. China has developed an extensive capability to design, test and produce military aircraft, missiles and space vehicles. Despite the cancellation in 1983 of the experimental Shanghai Y-10, China is still developing its civil aerospace industry.

The aircraft parts industry was born out of the sale of second-hand or used aircraft parts from the aerospace manufacture sector. Within the United States there is a specific process that parts brokers or resellers must follow. This includes leveraging a certified repair station to overhaul and "tag" a part. This certification guarantees that a part was repaired or overhauled to meet OEM specifications. Once a part is overhauled its value is determined from the supply and demand of the aerospace market. When an airline has an aircraft on the ground, the part that the airline requires to get the plane back into service becomes invaluable. This can drive the market for specific parts. There are several online marketplaces that assist with the commodity selling of aircraft parts.

In the aerospaces & defense industry, a lot of consolidation has appeared over the last couple of decades. Between 1988 and 2011, worldwide more than 6,068 mergers & acquisitions with a total known value of 678 bil. USD have been announced. The largest transactions have been:

• The acquisition of Rockwell Collins by United Technologies Corporation for 30.0 bil. USD in 2018
• The acquisition of Goodrich Corporation by United Technologies Corporation for 16.2 bil. USD in 2011
• Allied Signal merged with Honeywell in a stock swap valued 15.6 bil. USD in 1999
• The merger of Boeing with McDonnell valued at 13.4 bil. USD in 1996
• Marconi Electronic Systems, a subsidiary of GEC, was acquired by British Aerospace for 12.9 bil. USD in 1999 (now called: BAE Systems)
• Raytheon acquired Hughes Aircraft for 9.5 bil. USD in 1997

Technology

Multiple technologies and innovations are used in aerospace, many of them pioneered around World War II:

• patented by Short Brothers, folding wings optimise aircraft carrier storage from a simple fold to the entire rotating wing of the V-22, and the 12 ft (3.7 m) wingtip fold of the Boeing 777X for airport compatibility.
• To improve low-speed performance, a de Havilland DH4 was modified by Handley Page to a monoplane with high-lift devices: full-span leading-edge slats and trailing-edge flaps; in 1924, Fowler flaps that extend backward and downward were invented in the US, and used on the Lockheed Model 10 Electra while in 1943 forward-hinged leading-edge Krueger flaps were invented in Germany and later used on the Boeing 707.
• The 1927 large Propeller Research Tunnel at NACA Langley confirmed that the landing gear was a major source of drag, in 1930 the Boeing Monomail featured a retractable gear.
• The flush rivet displaced the domed rivet in the 1930s and pneumatic rivet guns work in combination with a heavy reaction bucking bar; not depending on plastic deformation, specialist rivets were developed to improve fatigue life as shear fasteners like the Hi-Lok, threaded pins tightened until a collar breaks off with enough torque.
• First flown in 1935, the Queen Bee was a radio-controlled target drone derived from the Tiger Moth for Flak training; the Ryan Firebee was a jet-powered target drone developed into long-range reconnaissance UAVs: the Ryan Model 147 Fire Fly and Lightning Bug; the Israeli IAI Scout and Tadiran Mastiff launched a line of battlefield UAVs including the IAI Searcher; developed from the General Atomics GNAT long-endurance UAV for the CIA, the MQ-1 Predator led to the armed MQ-9 Reaper.
• At the end of World War I, piston engine power could be boosted by compressing intake air with a compressor, also compensating for decreasing air density with altitude, improved with 1930s turbochargers for the Boeing B-17 and the first pressurized airliners.
• The 1937 Hindenburg disaster ended the era of passenger airships but the US Navy used airships for anti-submarine warfare and airborne early warning into the 1960s, while small airships continue to be used for aerial advertising, sightseeing flights, surveillance and research, and the Airlander 10 or the Lockheed Martin LMH-1 continue to be developed.
• As US airlines were interested in high-altitude flying in the mid-1930s, the Lockheed XC-35 with a pressurized cabin was tested in 1937 and the Boeing 307 Stratoliner was developed as the first pressurized airliner.
• In 1933, Plexiglas, a transparent Acrylic plastic, was introduced in Germany and shortly before World War II, was first used for aircraft windshields as it is lighter than glass, and the bubble canopy improved fighter pilots visibility.
• In January 1930, Royal Air Force pilot and engineer Frank Whittle filed a patent for a gas turbine aircraft engine with an inlet, compressor, combustor, turbine and nozzle, while an independent turbojet was developed by researcher Hans von Ohain in Germany; both engines ran within weeks in early 1937 and the Heinkel HeS 3-propelled Heinkel He 178 experimental aircraft made its first flight on Aug 27, 1939 while the Whittle W.1-powered Gloster E.28/39 prototype flew on May 15, 1941.
• In 1935, Britain demonstrated aircraft radio detection and ranging and in 1940 the RAF introduced the first VHF airborne radars on Bristol Blenheims, then higher-resolution microwave-frequency radar with a cavity magnetron on Bristol Beaufighters in 1941, and in 1959 the radar-homing Hughes AIM-4 Falcon became the first US guided missile on the Convair F-106.
• In the early 1940s, British Hurricane and Spitfire pilots wore g-suits to prevent G-LOC due to blood pooling in the lower body in high g situations; Mayo Clinic researchers developed air-filled bladders to replace water-filled bladders and in 1943 the US military began using pressure suits from the David Clark Company.
• The modern ejection seat was developed during World War II, a seat on rails ejected by rockets before deploying a parachute, which could have been enhanced by the USAF in the late 1960s as a turbojet-powered autogyro with 50 nm of range, the Kaman KSA-100 SAVER.
• In 1942, numerical control machining was conceived by machinist John T. Parsons to cut complex structures from solid blocks of alloy, rather than assembling them, improving quality, reducing weight, and saving time and cost to produce bulkheads or wing skins.
• In World War II, the German V-2 combined gyroscopes, an accelerometer and a primitive computer for real-time inertial navigation allowing dead reckoning without reference to landmarks or guide stars, leading to packaged IMUs for spacecraft and aircraft.
• The UK Miles M.52 supersonic aircraft was to have an afterburner, augmenting a turbojet thrust by burning additional fuel in the nozzle, but was cancelled in 1946.
• In 1935, German aerodynamicist Adolf Busemann proposed using swept wings to reduce high-speed drag and the Messerschmitt P.1101 fighter prototype was 80% complete by the end of World War II; the later US North American F-86 and Boeing B-47 flew in 1947, as the Soviet MiG-15, and the British de Havilland Comet in 1949.
• In 1951, the Avro Jetliner featured an ice protection system from Goodyear through electro-thermal resistances in the wing and tail leading edges; jet aircraft use hot engine bleed air and lighter aircraft use pneumatic deicing boots or weep anti-icing fluid on propellers, wing and tail leading edges.
• In 1954, Bell Labs developed the first transistorized airborne digital computer, Tradic for the US Boeing B-52 and in the 1960s Raytheon built the MIT-developed Apollo Guidance Computer; the MIL-STD-1553 avionics digital bus was defined in 1973 then first used in the General Dynamics F-16, while the civil ARINC 429 was first used in the Boeing 757/B767 and Airbus A310 in the early 1980s.
• After World War II, the initial promoter of Photovoltaic power for spacecraft, Hans K. Ziegler, was brought to the US under Operation Paperclip along Wernher von Braun and Vanguard 1 was its first application in 1958, later enhanced in space-deployable structures like the International Space Station solar arrays of 0.33 hectares (0.82 acres).
• To board an airliner, jet bridges are more accessible, comfortable and efficient than climbing the stairs.
• In the 1950s, to improve thrust and fuel efficiency, the jet engine airflow was divided into a core stream and a bypass stream with a lower velocity for better propulsive efficiency: the first was the Rolls-Royce Conway with a 0.3 BPR on the Boeing 707 in 1960, followed by the Pratt & Whitney JT3D with a 1.5 BPR and, derived from the J79, the General Electric CJ805 powered the Convair 990 with a 28% lower cruise fuel burn; bypass ratio improved to the 9.3 BPR Rolls-Royce Trent XWB, the 10:1 BPR GE9X and the Pratt & Whitney GTF with high-pressure ratio cores.

Functional safety

Functional safety relates to a part of the general safety of a system or a piece of equipment. It implies that the system or equipment can be operated properly and without causing any danger, risk, damage or injury. 

Functional safety is crucial in the aerospace industry, which allows no compromises or negligence. In this respect, supervisory bodies, such as the European Aviation Safety Agency (EASA ), regulate the aerospace market with strict certification standards. This is meant to reach and ensure the highest possible level of safety. The standards AS 9100 in America, EN 9100 on the European market or JISQ 9100 in Asia particularly address the aerospace and aviation industry. These are standards applying to the functional safety of aerospace vehicles. Some companies are therefore specialized in the certification, inspection verification and testing of the vehicles and spare parts to ensure and attest compliance with the appropriate regulations. 

Spinoffs

Spinoffs refer to any technology that is a direct result of coding or products created by NASA and redesigned for an alternate purpose. These technological advancements are one of the primary results of the aerospace industry, with $5.2 billion worth of revenue generated by spinoff technology, including computers and cellular devices. These spinoffs have applications in a variety of different fields including medicine, transportation, energy, consumer goods, public safety and more. NASA publishes an annual report called “Spinoffs”, regarding many of the specific products and benefits to the aforementioned areas in an effort to highlight some of the ways funding is put to use. For example, in the most recent edition of this publication, “Spinoffs 2015”, endoscopes are featured as one of the medical derivations of aerospace achievement. This device enables more precise and subsequently cost-effective neurosurgery by reducing complications through a minimally invasive procedure that abbreviates hospitalization.

Space launch

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Space_launch

 

Space launch is the earliest part of a flight that reaches space. Space launch involves liftoff, when a rocket or other space launch vehicle leaves the ground, floating ship or midair aircraft at the start of a flight. Liftoff is of two main types: rocket launch (the current conventional method), and non-rocket spacelaunch (where other forms of propulsion are employed, including airbreathing jet engines or other kinds).

Issues with reaching space

Definition of space

Space has no physical edge to it as the atmospheric pressure gradually reduces with altitude; instead, the edge of space is defined by convention, often the Kármán line of 100 km. Other definitions have been created as well. In the US for example space has been defined as 50 miles.

Energy

Therefore, by definition for spaceflight to occur, sufficient altitude is necessary. This implies a minimum gravitational potential energy needs to be overcome: for the Kármán line this is approximately 1 MJ/kg. W=mgh, m=1 kg, g=9.82 m/s², h=10⁵m. W=1*9.82*10⁵≈10⁶J/kg=1MJ/kg.

In practice, a higher energy than this is needed to be expended due to losses such as airdrag, propulsive efficiency, cycle efficiency of engines that are employed and gravity drag.

In the past fifty years spaceflight has usually meant remaining in space for a period of time, rather than going up and immediately falling back to earth. This entails orbit, which is mostly a matter of velocity, not altitude, although that does not mean air friction and relevant altitudes in relation to that and orbit don't have to be taken into account. At much, much higher altitudes than many orbital ones maintained by satellites, altitude begins to become a larger and larger factor and speed a lesser one. At lower altitudes, due to the high speed required to remain in orbit, air friction is a very important consideration affecting satellites, much more than in the popular image of space. At even lower altitudes, balloons, with no forward velocity, can serve many of the roles satellites play. 

G-forces

Many cargoes, particularly humans have a limiting g-force that they can survive. For humans this is about 3-6 g. Some launchers such as gun launchers would give accelerations in the hundred or thousands of g and thus are completely unsuitable. 

Reliability

Launchers vary with respect to their reliability for achieving the mission. 

Safety

Safety is the probability of causing injury or loss of life. Unreliable launchers are not necessarily unsafe, whereas reliable launchers are usually, but not invariably safe.

Apart from catastrophic failure of the launch vehicle itself other safety hazards include depressurisation, and the Van Allen radiation belts which preclude orbits which spend long periods within them. 

Trajectory optimisation

Trajectory optimization is the process of designing a trajectory that minimizes or maximizes some measure of performance within prescribed constraint boundaries. While not exactly the same, the goal of solving a trajectory optimization problem is essentially the same as solving an optimal control problem. This problem was first studied by Robert H. Goddard and is also known as the Goddard problem.

The selection of flight profiles that yield the greatest performance plays a substantial role in the preliminary design of flight vehicles, since the use of ad-hoc profile or control policies to evaluate competing configurations may inappropriately penalize the performance of one configuration over another. Thus, to guarantee the selection of the best vehicle design, it is important to optimize the profile and control policy for each configuration early in the design process.

For example, for tactical missiles, the flight profiles are determined by the thrust and load factor (lift) histories. These histories can be controlled by a number of means including such techniques as using an angle of attack command history or an altitude/downrange schedule that the missile must follow. Each combination of missile design factors, desired missile performance, and system constraints results in a new set of optimal control parameters.

Sustained spaceflight

Suborbital launch

Sub-orbital space flight is any space launch that reaches space without doing a full orbit around the planet, and requires a maximum speed of around 1 km/s just to reach space, and up to 7 km/s for longer distance such as an intercontinental space flight. An example of a sub-orbital flight would be a ballistic missile, or future tourist flight such as Virgin Galactic, or an intercontinental transport flight like SpaceLiner. Any space launch without an orbit-optimization correction to achieve a stable orbit will result in a suborbital space flight, unless there is sufficient thrust to leave orbit completely.

Orbital launch

In addition, if orbit is required, then a much greater amount of energy must be generated in order to give the craft some sideways speed. The speed that must be achieved depends on the altitude of the orbit – less speed is needed at high altitude. However, after allowing for the extra potential energy of being at higher altitudes, overall more energy is used reaching higher orbits than lower ones.

The speed needed to maintain an orbit near the Earth's surface corresponds to a sideways speed of about 7.8 km/s (17,400 mph), an energy of about 30MJ/kg. This is several times the energy per kg of practical rocket propellant mixes. 

Gaining the kinetic energy is awkward as the airdrag tends to slow the spacecraft, so rocket-powered spacecraft generally fly a compromise trajectory that leaves the thickest part of the atmosphere very early on, and then fly on for example, a Hohmann transfer orbit to reach the particular orbit that is required. This minimises the airdrag as well as minimising the time that the vehicle spends holding itself up. Airdrag is a significant issue with essentially all proposed and current launch systems, although usually less so than the difficulty of obtaining enough kinetic energy to simply reach orbit at all. 

Escape velocity

If the Earth's gravity is to be overcome entirely then sufficient energy must be obtained by a spacecraft to exceed the depth of the gravity potential energy well. Once this has occurred, provided the energy is not lost in any non-conservative way, then the vehicle will leave the influence of the Earth. The depth of the potential well depends on the vehicle's position, and the energy depends on the vehicle's speed. If the kinetic energy exceeds the potential energy then escape occurs. At the Earth's surface this occurs at a speed of 11.2 km/s (25,000 mph), but in practice a much higher speed is needed due to airdrag. 

Types of space launch

Rocket launch

Rocket launch is the only current way to reach space. In some cases an airbreathing (jet engine) first stage has been used as well. 

Non-rocket launch

Non-rocket space launch is a launch into space where some or all of the needed speed and altitude are provided by something other than expendable rockets. A number of alternatives to expendable rockets have been proposed. In some systems such as Skyhooks, rocket sled launch, and air launch, a rocket is used to reach orbit, but it is only part of the system.

Spacecraft

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Spacecraft 

 

More than 100 Soviet and Russian crewed Soyuz spacecraft (TMA version shown) have flown since 1967 and now support the International Space Station.

 

The US Space Shuttle flew 135 times from 1981 to 2011, supporting Spacelab, Mir, the Hubble Space Telescope, and the ISS. (Columbia's first launch, which had a white external tank, shown)

 

A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, planetary exploration, and transportation of humans and cargo. All spacecraft except single-stage-to-orbit vehicles cannot get into space on their own, and require a launch vehicle (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 orbit of the Earth. 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 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 method of reentry to Earth into non-winged space capsules and winged spaceplanes.

Humanity has achieved space flight but only a few nations have the technology for orbital launches: Russia (RSA or "Roscosmos"), the United States (NASA), the member states of the European Space Agency (ESA), Japan (JAXA), China (CNSA), India (ISRO), Taiwan (National Chung-Shan Institute of Science and Technology, Taiwan National Space Organization (NSPO), Israel (ISA), Iran (ISA), and North Korea (NADA). 

History

The first artificial satellite, Sputnik 1. It was launched by the Soviet Union

 

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 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, through 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 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 kilometers (18,000 mi) per hour, 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 man-made objects had previously reached an altitude of 100 km, which 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. 

Spacecraft types

Crewed spacecraft

Apollo 17 Command Module in Lunar orbit

 

As of 2016, only three nations have flown crewed spacecraft: USSR/Russia, USA, and China. The first crewed spacecraft 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 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, Apollo spacecraft including the Apollo Lunar Module, the Skylab space station, and the Space Shuttle with undetached European Spacelab and private US Spacehab space stations-modules. China developed, but did not fly Shuguang, and is currently using Shenzhou (its first crewed mission was in 2003).

Except for the Space Shuttle, all of the recoverable crewed orbital spacecraft were space capsules.

• Crewed space capsules
  
• 

  American Mercury, Gemini, and Apollo spacecraft
  
  
• 

  Soviet Voskhod (variant of Vostok)
  
  
• 

  1967 Soviet/Russian Soyuz spacecraft
  
  
• 

  Chinese Shenzhou
  
  
• 

  Line drawing of Vostok capsule
  

The International Space Station, crewed since November 2000, is a joint venture between Russia, the United States, Canada and several other countries.

Spaceplanes

Columbia orbiter landing

 

Some reusable vehicles have been designed only for crewed spaceflight, and these are often called spaceplanes. The first example of such was the North American X-15 spaceplane, which conducted two crewed flights which reached an altitude of over 100 km in the 1960s. The first reusable spacecraft, the X-15, was air-launched on a suborbital trajectory on July 19, 1963.

The first partially reusable orbital spacecraft, a winged non-capsule, the Space Shuttle, 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 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 automatic partially reusable spacecraft 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 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 due mainly 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 Dragon 2 and Boeing's CST-100 Starliner no earlier than 2020. The Shuttle's heavy cargo transport role 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 will build its successor SpaceShipTwo. A fleet of SpaceShipTwos operated by Virgin Galactic was planned to begin reusable private spaceflight carrying paying passengers in 2014, but was delayed after the crash of VSS Enterprise. 

Uncrewed spacecraft

Hubble Space Telescope

 

Jules Verne Automated Transfer Vehicle (ATV) approaches the International Space Station on Monday, March 31, 2008

 

Mariner 10 diagram of trajectory past planet Venus

 

Designed as crewed but flown as non-crewed only spacecraft

• Zond/L1 – lunar flyby capsule
• L3 – capsule and lunar lander
• TKS – capsule
• Buran-class shuttle – Soviet shuttle

Semi-crewed – crewed as space stations or part of space stations

• Progress – uncrewed USSR/Russia cargo spacecraft
• TKS – unmanned USSR/Russia cargo spacecraft and space station module
• Automated Transfer Vehicle (ATV) – uncrewed European cargo spacecraft
• H-II Transfer Vehicle (HTV) – uncrewed Japanese cargo spacecraft
• SpaceX Dragon – uncrewed private spacecraft
• Tianzhou 1 – China's uncrewed spacecraft

Earth-orbit satellites

• Explorer 1 – first US satellite
• Project SCORE – first communications satellite
• Solar and Heliospheric Observatory (SOHO) - orbits the Sun near L1
• Sputnik 1 – world's first artificial satellite
• Sputnik 2 – first animal in orbit (Laika)
• Korabl-Sputnik 2 – first capsule recovered from orbit (Vostok precursor) – animals survived
• Syncom – first geosynchronous communications satellite
• Hubble Space Telescope – largest orbital observatory
• X-37 – spaceplane

Lunar probes

• Clementine – US Navy mission, orbited Moon, detected hydrogen at the poles
• Kaguya JPN – lunar orbiter
• Luna 1 – first lunar flyby
• Luna 2 – first lunar impact
• Luna 3 – first images of lunar far side
• Luna 9 – first soft landing on the Moon
• Luna 10 – first lunar orbiter
• Luna 16 – first uncrewed lunar sample retrieval
• Lunar Orbiter – very successful series of lunar mapping spacecraft
• Lunar Prospector – confirmed detection of hydrogen at the lunar poles
• Lunar Reconnaissance Orbiter – Identifies safe landing sites and locates Moon resources
• Lunokhod - Soviet lunar rovers
• SMART-1 ESA – Lunar Impact
• Surveyor – USA's first soft lander
• Chang'e 1 – China's Chang'e lunar mission
• Chang'e 2 – China's Chang'e lunar mission
• Chang'e 3 – China's Chang'e lunar mission
• Chandrayaan 1 – first Indian Lunar mission
• Chandrayaan 2 – second Indian Lunar mission

Artist's conception of Cassini–Huygens as it enters Saturn's orbit

 

Artist's conception of the Phoenix spacecraft as it lands on Mars

 

Planetary probes

• Akatsuki JPN – a Venus orbiter
• Cassini–Huygens – first Saturn orbiter and Titan lander
• Curiosity – Rover sent to Mars by NASA in 2012
• Galileo – first Jupiter orbiter and descent probe
• IKAROS JPN – first solar-sail spacecraft
• Mariner 4 – first Mars flyby, first close and high resolution images of Mars
• Mariner 9 – first Mars orbiter
• Mariner 10 – first Mercury flyby, first close up images
• Mars Exploration Rovers (Spirit and Opportunity)– Mars rovers
• Mars Express – Mars orbiter
• Mars Global Surveyor – Mars orbiter
• Mars Orbiter Mission (Mangalyaan) - India's first Interplanetary probe
• Mars Reconnaissance Orbiter – an advanced climate, imaging, sub-surface radar, and telecommunications Mars orbiter
• MESSENGER – first Mercury orbiter (arrival 2011)
• Mars Pathfinder – Mars lander, carrying the Sojourner rover
• New Horizons – first Pluto flyby (arrival 2015)
• Pioneer 10 – first Jupiter flyby, first close up images
• Pioneer 11 – second Jupiter flyby and first Saturn flyby (first close up images of Saturn)
• Pioneer Venus – first Venus orbiter and landers
• Vega 1 – Balloon release into Venus atmosphere and lander, mothership continued on to fly by Halley's Comet. Joint mission with Vega 2.
• Venera 4 – first soft landing on another planet (Venus)
• Viking 1 – first soft landing on Mars
• Voyager 1 - flybys of Jupiter, Saturn, and Saturn's moon Titan
• Voyager 2 – Jupiter flyby, Saturn flyby, and first flybys/images of Neptune and Uranus

Other – deep space

• Cluster
• Deep Space 1
• Deep Impact
• Genesis
• Hayabusa
• Near Earth Asteroid Rendezvous
• Rosetta
• Stardust
• STEREO – Heliospheric and solar sensing; first images of the entire Sun
• WMAP

Fastest spacecraft

• Parker Solar Probe (estimated 343,000 km/h or 213,000 mph at first sun close pass, will reach 700,000 km/h or 430,000 mph at final perihelion)

• Helios I and II Solar Probes (252,792 km/h or 157,078 mph)

Furthest spacecraft from the Sun

• Voyager 1 at 144.20 AU as of December 2018, traveling outward at about 3.58 AU/a (61,100 km/h; 38,000 mph)

• Pioneer 10 at 122.48 AU as of December 2018, traveling outward at about 2.52 AU/a (43,000 km/h; 26,700 mph)

• Voyager 2 at 119.34 AU as of December 2018, traveling outward at about 3.24 AU/a (55,300 km/h; 34,400 mph)
• Pioneer 11 at 101.17 AU as of December 2018, traveling outward at about 2.37 AU/a (40,400 km/h; 25,100 mph)

Unfunded and canceled programs

The first test flight of the Delta Clipper-Experimental Advanced (DC-XA), a prototype launch system

Crewed spacecraft

• Chinese Shuguang capsule
• Soviet Soyuz Kontakt capsule
• Soviet Almaz space station
• US Manned Orbiting Laboratory space station
• US Altair lunar lander

Multi-stage spaceplanes

• US X-20 spaceplane
• Soviet Spiral shuttle
• Soviet/Russian Buran-class shuttle
• ESA Hermes shuttle
• Kliper Russian semi-shuttle/semi-capsule
• Japanese HOPE-X shuttle
• Chinese Shuguang Project 921-3 shuttle

SSTO spacecraft

• RR/British Aerospace HOTOL
• ESA Hopper Orbiter
• US DC-X (Delta Clipper)
• US Roton Rotored-Hybrid
• US VentureStar

Spacecraft under development

NASA's Orion Spacecraft for the Artemis 1 mission seen in Plum Brook On December 1, 2019

Crewed

• (US-NASA; Europe-ESA) Orion – capsule
• (US-SpaceX) Dragon 2 – capsule
• (US-Boeing) CST-100 – capsule
• (US-Sierra Nevada Corporation) Dream Chaser – orbital spaceplane
• (US-The SpaceShip company) SpaceShipTwo suborbital spaceplane
• (US-Blue Origin) New Shepard – VTVL capsule
• (US-XCOR) Lynx rocketplane – suborbital spaceplane
• China Shenzhou spacecraft
• (India-DRDO) Avatar RLV -Under development, First demonstration flight planned in 2015.
• (India-ISRO) Gaganyaan – capsule
• (India-ISRO) RLV Technology Demonstration Programme – spacecraft
• SpaceX Starship – VTVL spacecraft
• (Russia-RKA) Orel – capsule
• (Europe-ESA) Advanced Crew Transportation System – capsule
• (Iranian Space Agency) Orbital Vehicle – capsule

Uncrewed

• ESA and JAXA BepiColombo - Planetary Probe to Mercury
• China Shenzhou (spacecraft) Cargo
• CNES Mars Netlander
• Orbital Sciences Cygnus – cargo delivery to the ISS
• Darwin14 ESA probe
• James Webb Space Telescope (delayed)
• Mars 2020 rover
• Reaction Engines Limited
• Skylon
• SpaceX Dragon – cargo delivery to the ISS
• StarChip and Sprites - miniaturized interstellar spacecraft
• System F6—a DARPA Fractionated Spacecraft demonstrator
• Terrestrial Planet Finder cancelled probe

Subsystems

A spacecraft system comprises various subsystems, depending on the mission profile. Spacecraft subsystems comprise the spacecraft's "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.

Life support

Spacecraft intended for human spaceflight must also include a life support system for the crew.

Reaction control system thrusters on the front of the U.S. Space Shuttle

Attitude control

A Spacecraft needs an attitude control subsystem to be correctly oriented in space and respond to external torques and forces properly. The attitude control subsystem consists of sensors and actuators, together with controlling algorithms. The attitude-control subsystem permits proper pointing for the science objective, sun pointing for power to the solar arrays and earth pointing for communications.

GNC

Guidance refers to the calculation of the commands (usually done by the CDH subsystem) needed to steer the spacecraft where it is desired to be. Navigation means determining a spacecraft's orbital elements or position. Control means adjusting the path of the spacecraft to meet mission requirements.

Command and data handling

The CDH subsystem receives commands from the communications subsystem, performs validation and decoding of the commands, and distributes the commands to the appropriate spacecraft subsystems and components. The CDH also receives housekeeping data and science data from the other spacecraft subsystems and components, and packages the data for storage on a data recorder or transmission to the ground via the communications subsystem. Other functions of the CDH include maintaining the spacecraft clock and state-of-health monitoring.

Communications

Spacecraft, both robotic and crewed, utilize various communications systems for communication with terrestrial stations as well as for communication between spacecraft in space. Technologies utilized include RF and optical communication. In addition, some spacecraft payloads are explicitly for the purpose of ground–ground communication using receiver/retransmitter electronic technologies.

Power

Spacecraft need an electrical power generation and distribution subsystem for powering the various spacecraft subsystems. For spacecraft near the Sun, solar panels are frequently used to generate electrical power. Spacecraft designed to operate in more distant locations, for example Jupiter, might employ a radioisotope thermoelectric generator (RTG) to generate electrical power. Electrical power is sent through power conditioning equipment before it passes through a power distribution unit over an electrical bus to other spacecraft components. Batteries are typically connected to the bus via a battery charge regulator, and the batteries are used to provide electrical power during periods when primary power is not available, for example when a low Earth orbit spacecraft is eclipsed by Earth.

Thermal control

Spacecraft must be engineered to withstand transit through Earth's atmosphere and the space environment. They must operate in a vacuum with temperatures potentially ranging across hundreds of degrees Celsius as well as (if subject to reentry) in the presence of plasmas. Material requirements are such that either high melting temperature, low density materials such as beryllium and reinforced carbon–carbon or (possibly due to the lower thickness requirements despite its high density) tungsten or ablative carbon–carbon composites are used. Depending on mission profile, spacecraft may also need to operate on the surface of another planetary body. The thermal control subsystem can be passive, dependent on the selection of materials with specific radiative properties. Active thermal control makes use of electrical heaters and certain actuators such as louvers to control temperature ranges of equipments within specific ranges.

Spacecraft propulsion

Spacecraft may or may not have a propulsion subsystem, depending on whether or not the mission profile calls for propulsion. The Swift spacecraft is an example of a spacecraft that does not have a propulsion subsystem. Typically though, LEO spacecraft include a propulsion subsystem for altitude adjustments (drag make-up maneuvers) and inclination adjustment maneuvers. A propulsion system is also needed for spacecraft that perform momentum management maneuvers. Components of a conventional propulsion subsystem include fuel, tankage, valves, pipes, and thrusters. The thermal control system interfaces with the propulsion subsystem by monitoring the temperature of those components, and by preheating tanks and thrusters in preparation for a spacecraft maneuver.

Structures

Spacecraft must be engineered to withstand launch loads imparted by the launch vehicle, and must have a point of attachment for all the other subsystems. Depending on mission profile, the structural subsystem might need to withstand loads imparted by entry into the atmosphere of another planetary body, and landing on the surface of another planetary body.

Payload

The payload depends on the mission of the spacecraft, and is typically regarded as the part of the spacecraft "that pays the bills". Typical payloads could include scientific instruments (cameras, telescopes, or particle detectors, for example), cargo, or a human crew.

Ground segment

The ground segment, though not technically part of the spacecraft, is vital to the operation of the spacecraft. Typical components of a ground segment in use during normal operations include a mission operations facility where the flight operations team conducts the operations of the spacecraft, a data processing and storage facility, ground stations to radiate signals to and receive signals from the spacecraft, and a voice and data communications network to connect all mission elements.

Launch vehicle

The launch vehicle propels the spacecraft from Earth's surface, through the atmosphere, and into an orbit, the exact orbit being dependent on the mission configuration. The launch vehicle may be expendable or reusable.