Space travel

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Buzz Aldrin ,
second man on the moon (July 1969, Apollo 11 )

As space (including space travel , astronautics or astronautics called) travel or transportation is to or through the space designated. The transition between earth and space is fluid, it was set by the US Air Force at a limit altitude of 50 miles (~ 80 km) and by the Fédération Aéronautique Internationale (FAI) at a limit altitude of 100 kilometers (for the latter see Kármán line ). Both defined heights are in the high atmosphere .

While the theory of space travel was developed by Konstantin Eduardowitsch Ziolkowski with the formulation of the rocket equations as early as 1900 , the first solid rocket had been around for many centuries. The first liquid rockets were developed from the 1920s by Robert Goddard and, during the Second World War , by Wernher von Braun .

The start of practical space travel was the start of Sputnik 1 by the Soviet Union on October 4, 1957. Milestones in manned space travel included Vostok 1 with Yuri Gagarin in 1961 as the first person in space, and in 1969 the first manned moon landing with Apollo 11 with Salyut 1 the first manned space station in 1971 or the first reusable spacecraft with the space shuttle Space Shuttle 1981. By the end of 2017 there were over 500 people in space (see list of space travelers ). In unmanned space travel, space probes have explored the moon and planets. Communication satellites operate in large numbers in geostationary positions. Navigation satellites orbit the earth so that as many satellites as possible can be received from anywhere on earth. Earth observation satellites provide high resolution images for commercial and military purposes.

Preliminary remark

The chronological list of previous space missions is divided into:

In addition, there are the main articles

as well as main article about

The space travel article summarizes the most important aspects and deals with the basics of space travel.

history

Although the idea of ​​traveling to the moon or other planets and stars has long existed, it was not until the 20th century, with the development of rocket technology, that the only techniques with which a sufficiently high speed could be achieved emerged. For a simple orbit this is at least 7.9 km / s from earth (see cosmic speed ).

Theoretical foundations and rocket pioneers

Konstantin Eduardowitsch Ziolkowski

The Russian Konstantin Ziolkowski (1857–1935) was the first to study the theory of space travel in more detail: He formulated the basic mathematical principles of rocket propulsion and the fundamental rocket equation . The German Hermann Oberth (1894–1989) also set up the basic equation of rocket technology in 1923 and, like Ziolkowski, showed with the concept of the step rocket how large payloads can be brought into the desired trajectory in an energetically favorable manner.

The South Tyrolean astronomer and rocket pioneer Max Valier (1895–1930) and the American R. H. Goddard (1882–1945) should be mentioned among the first engineers and experimental scientists . Valier was the first European to venture into experiments with liquid fuels and, among other things, built a rocket car (exhibited in the Deutsches Museum ). During a laboratory test in Berlin, an aggregate exploded and a metal splinter killed the 35-year-old. From around 1910 Goddard developed small rocket motors with which he succeeded in launching the first liquid rocket in 1926 .

Other well-known pioneers are:

The military and industry are discovering space travel

This process first began in the German Reich , which recognized the new technology as a way of circumventing the provisions of the Versailles Treaty . Until the outbreak of the Second World War , the Peenemünde Army Research Center was established under Wernher von Braun , where the A4 / V2 rocket was finally built. The A4 was designed as a long -range ballistic artillery missile and was the first man-made object to penetrate the boundary into space (the Kármán line, as defined by the FAI, at an altitude of more than 100 km ). This first large missile in the world was used as a long-range weapon mainly against London and Antwerp . Due to the relative inaccuracy of the hit and the extraordinarily poor relationship between cost and destructive effect, this type of missile was a wrong decision in terms of military economy. The military strategists and politicians of the Soviet Union and the USA recognized the potential of rocket technology, which lay primarily in the fact that rockets could practically not be intercepted, and tried to steal not only equipment and blueprints , but also practical knowledge from occupied Germany . A race between the two states that was to last for decades began in the last days of the Second World War. After the war, complete rockets as well as production facilities and numerous scientists and technicians were brought to the USA and the Soviet Union, where they formed the basis of rocket development for the next few decades (see Operation Paperclip ).

Race into space in the Cold War

"Ham the Astrochimp," a 44-month-old chimpanzee who was launched into space on January 31, 1961 as part of the Mercury program

In the Cold War , which was now beginning , space travel was of particular importance in terms of mass psychology and propaganda . In addition to its obvious military value, contemporaries perceived it as a yardstick for the efficiency and progressiveness of the two competing systems. In the USA, Wernher von Braun was largely responsible for the progress in development and was accordingly present in public, while his counterpart Sergei Koroljow was almost unknown even in the Soviet Union .

As a result of the so-called Sputnik shock in October 1957, the American public suddenly became aware that the Soviet Union had almost completely caught up with the original technological deficit. From this point on, space travel was promoted to the best of its ability in the United States, and a real race ensued. The Soviet space now reach many important firsts. She brought the bitch, Laika , into space a month after the start of Sputnik 1 . On April 12, 1961, Yuri Gagarin became the first person in space to orbit the earth. In 1959 and 1966, the Lunik 2 and Luna 9 probes performed hard and soft landings on the moon for the first time . In contrast, US efforts under President Kennedy concentrated on the manned moon landing , which was followed on July 20, 1969 by half a billion television viewers.

Although the civil space agency NASA was and still is the focus of the public, the development of space travel, apart from the prestige projects that attract public attention, was determined exclusively by military considerations. About three quarters of all satellite launches serve and served military purposes. The USA had had reconnaissance satellites since 1959 and weather , navigation and early warning satellites since 1960 .

The Soviet Union continued the research it had started in the 1960s on coupling maneuvers, long-term flights and space exits by cosmonauts , via the first Salyut  1 space station to joint coupling maneuvers with the USA in 1975 and finally the permanently manned Mir space station .

Space cooperation and globalization

Space station Mir

Even during the Mir era, there was an increased willingness to cooperate between the USA and Russia . The space shuttle docked several times with the aging space station and thus made a significant contribution to its preservation.

The joint efforts finally culminated in the planning and construction of the International Space Station (ISS) from 1998. After the crash of the Columbia space shuttle in 2003, it was only accessible by Soyuz spaceships , as has been the case since the space shuttle fleet was decommissioned in 2011. Operation the ISS has been Template: future / in 4 yearsagreed at least until 2024 , an extension until 2028 Template: future / in 5 yearsis possible.

Milestones in space travel (selection)

Space Shuttle Columbia
  • October 3, 1942: First successful launch of an A4 rocket (also known as the V2). However , the A4 does not reach the first cosmic speed required to go into earth orbit. ( German Empire )
  • June 20, 1944: The A4 rocket MW 18014 reaches a height of over 100 km, making it the first man-made object that crosses the boundaries of space, the Kármán line . (German Empire)
  • February 20, 1947: First animals in space: Fruit flies are transported by the Americans into space with a V2 rocket at an altitude of 109 kilometers to test the effects of radiation. ( USA )
  • June 14, 1949: The rhesus monkey Albert II is the first mammal to be brought to an altitude of 134 kilometers by a V2 rocket from the US, but then dies on impact on the earth. (UNITED STATES)
  • October 4, 1957: Launch of Sputnik 1 , the first human-made satellite . ( Soviet Union )
  • November 3, 1957: Sputnik 2 , with the dog Laika, brings a living being into orbit for the first time. (Soviet Union)
  • September 13, 1959: The first human-made missile, Lunik 2 , hits the surface of the moon. (Soviet Union)
  • October 7, 1959: Lunik 3 photographs the back of the moon . (Soviet Union)
  • August 19, 1960: With Sputnik 5, two living beings (the bitches Strelka and Belka) land safely on earth for the first time after a space flight. (Soviet Union)
  • April 12, 1961: Vostok 1 . Yuri Gagarin is the first person to fly into space and orbit the earth. (Soviet Union)
  • May 5, 1961: Alan Shepard is the first American in space in a parabolic flight of a few minutes.
  • 11./12. August 1962: Vostok 3 and Vostok 4 : Andrijan Nikolajew and Pawel Popowitsch start the first space rendezvous . For the first time there are two people in space; the spaceships approach within 5 km. (Soviet Union)
  • June 16, 1963: Vostok 6 . Valentina Tereshkova is the first woman to fly into space. (Soviet Union)
  • March 18, 1965: Voschod 2 : Alexei Leonow is the first person to leave a spaceship and float freely in space. (Soviet Union)
  • February 3, 1966: The Luna 9 probe makes the first soft landing on another celestial body, the moon. (Soviet Union)
  • March 16, 1966: First coupling in manned space travel - Gemini 8 docks with an unmanned target satellite. (UNITED STATES)
  • December 21, 1968: Apollo 8 marks the first time humans leave Earth orbit. The crew consists of Frank Borman , James Lovell and William Anders . (UNITED STATES)
  • July 16, 1969: Apollo 11 , take off for the first moon landing. Neil Armstrong became the first person to set foot on the moon on July 21, 1969, followed by Buzz Aldrin . Michael Collins remains in lunar orbit. (UNITED STATES)
  • November 17, 1970: Lunochod 1 is the first rover to travel another celestial body, the moon. (Soviet Union)
  • December 15, 1970: Venera 7 makes the first soft landing on another planet, Venus. (Soviet Union)
  • December 3, 1973: Pioneer 10 is the first space probe to pass one of the outer planets of the solar system, Jupiter. (UNITED STATES)
  • December 24, 1979: First flight of the European Ariane 1 launcher . ( ESA )
  • April 12, 1981: Space Shuttle Columbia takes off on its maiden flight. It is the first partially reusable space transportation system. (UNITED STATES)
  • February 19, 1986: The base block of the Mir space station is launched into space. (Soviet Union)
  • November 20, 1998: With the start of the Russian Zarya module, the construction of the International Space Station begins - the largest project in space travel to date.
  • October 15, 2003: Yang Liwei is the first Chinese to go into space on the Shenzhou 5 mission .
  • June 21, 2004: The SpaceShipOne is the first privately operated manned spacecraft to enter space. (UNITED STATES)
  • October 24, 2007: China launches its first Chang'e-1 lunar probe .
  • October 22, 2008: India starts its first moon mission with Chandrayaan-1 . (India)
  • August 2012: Voyager 1 becomes the first human-made object to enter interstellar space . (UNITED STATES)
  • November 12, 2014: With the Philae probe launched by Rosetta , the soft landing on a comet , Churyumov-Gerassimenko, was achieved for the first time . (ESA)
  • November 23, 2015: The US space company Blue Origin succeeds with the New Shepard, the first controlled landing of a rocket after a flight into space.

Basics

Modern space propulsion works according to the recoil principle ( third Newtonian axiom ). Similar to a cannon that rolls back when a bullet is fired, a missile moves forward when it ejects mass from behind. The most important property of a rocket fuel from a propulsion point of view is its specific momentum , which is a measure of the effectiveness of the engine and fuel. The higher it is, the better the fuel and the engine. It indicates how long a mass of fuel M can generate a thrust of its weight. To be able to take off vertically from a celestial body like the earth, the thrust must be greater than the weight. So far, only chemical rocket engines and nuclear rocket engines are capable of doing this.

begin

Soyuz rocket launch

A distinction is made between orbital and suborbital space travel. To reach an orbit , a spacecraft must not only reach the minimum altitude but also the first cosmic speed of around 7.9 km / s in the horizontal direction in order to become an earth satellite. If the speed is lower, the trajectory corresponds to a ballistic curve . In order to achieve this high speed, launch vehicles are used according to the step principle , a distinction is made between tank, engine, parallel and tandem steps . Such a launcher is launched from a launch pad .

In space

requirements

Every man-made object, regardless of whether it is a spaceship, station or satellite, requires at least the following components:

satellite

A satellite (Latin for "bodyguard", "companion") is a spacecraft that orbits a celestial body - such as a planet or a moon - on an elliptical or circular orbit for the fulfillment of scientific, commercial or military purposes. Satellites that orbit a body other than the earth in order to explore it are (also) called orbiters.

Spacecraft

Spaceships are generally all vehicles that were created to move in space. The main propulsion in the vacuum is provided by conventional rocket engines. If people are on board, a life support system is necessary. Rockets that are single-stage only reach a limited height and therefore cannot leave the Earth's area of ​​attraction, which is why multi-stage rockets are used. They consist of several rockets coupled together.

Space stations

ISS in March 2009

Space stations are, since they themselves do not have a propulsion system for locomotion or landing devices, dependent on spacecraft for transport. They include laboratories , residential modules, air locks and an energy supply. The maintenance of the crew is a technical challenge when operating a space station. Due to the high costs of transport, systems have to be developed that allow the operation of a space station to be largely self-sufficient, i.e. in a closed circuit. Great progress has been made, particularly in the treatment of water and air. Space vehicles are used to exchange personnel, and space freighters are used to supply cargo, fuel and experiments.

Space transporter

Supply ships are used to supply space stations with cargo and fuel. These can be based on manned versions of spacecraft, such as the Russian Progress . Others can only be used for this purpose, such as the US Cygnus freighter.

Space probes

A space probe is an unmanned missile that is sent into space for exploration purposes. In contrast to a (earth) satellite, it leaves earth's orbit and flies to a distant target in space in order to investigate it. Because space probe missions often last for years, the technical equipment of space probes must meet the highest demands. The components of space probes are extensively tested and assembled in the clean room, which explains the high costs of space probes. A big problem with space probes compared to orbiting satellites is the great distance from the earth, which causes long transit times for the control commands sent by the ground station. For this reason, spacecraft must have systems that make them somewhat independent of ground stations. Depending on the task at hand, space probes are divided into:

  • Flyby probes - probes that only perform a flyby of a celestial body.
  • Orbiter - probes that go into orbit around a celestial body.
  • Landers - probes that land on a celestial body. A further subdivision is useful here:
    • Hydrobot - a probe that can independently explore the depths of unknown waters.
    • Cryobot - a probe that melts through ice to explore it and underlying media.
    • Penetrator - a space probe that bores / penetrates up to a few meters into the celestial body to be examined during an unrestrained landing.
    • Rover - a mobile landing device with which larger regions can be explored.
    • Sample return - probes that return samples from a celestial body or particles collected in space to the earth.
Atmospheric re-entry (artist's impression)

Spatial orientation

To control rocket launches , as well as satellites and other space probes, both with regard to their - multi-axis - alignment and their location deviation from a planned trajectory or the target of a path, an exact orientation (in the sense of navigation) in space is necessary. It is mostly done by gyro platforms that are either fixed in space (with regard to the astronomical coordinate system ) or are continuously readjusted to the curvature of the earth . This orientation is supported and corrected by star sensors . There is also gravitational stabilization based on the natural gravity gradient .

See also: spatial position , spatial orientation

landing

When entering the atmosphere, the spaceship or space probe is braked. Temperatures of over 1000 ° C occur here. Ablative heat shields are used for space capsules , and heat protection tiles for reusable systems such as the Space Shuttle . If there is no atmosphere, the speed has to be reduced completely by braking with rocket engines, for example when landing on the moon. It is placed either vertically with the engines running or horizontally.

Space states

The states that actively pursue spaceflight or participate extensively in programs in other countries or groups of states included (as of December 2012):
Argentina , Brazil , China , Europe ( ESA ), India , Iran , Israel , Japan , New Zealand , North Korea , Russia (and the former Soviet Union ), South Korea and the USA . The launch vehicles from Argentina and Brazil are currently under development.

Commercial and private space travel

The first area of ​​space travel to become commercially viable was communication satellites and television satellites . The first experimental communications satellite was the military SCORE . The first civil communications satellite was the passive Echo 1 , and the first active one was Telstar . The passive communication satellites turned out to be commercially unusable. At Telstar, the low orbit did not make sense. Systems in low orbits have therefore been replaced in the west by geostationary satellites . The first functional, still experimental, was Syncom 2 .

Then the telecommunications companies and authorities of the western world founded the satellite operator Intelsat for the commercial use of communications satellites . Purely private satellite operators also emerged in the USA in the following years. In Europe, communications satellite systems operated by state telecommunications authorities also emerged in some countries, which were later discontinued or privatized. In the case of television satellites, state systems have never really developed in Europe, and the private Astra system has dominated from the start . After Intelsat was privatized, communications satellites are only operated in exceptional cases by state organizations, such as military communications satellites and experimental satellites. The launch services for these satellites are also mostly offered by private companies (e.g. Arianespace ). In contrast, the launch vehicles they use are still being developed with taxpayers' money from space agencies, or the development is subsidized. There are very few completely privately financed carrier systems. Most are still at the planning stage or in development.

  • On June 21, 2004, SpaceShipOne, for the first time, a manned missile financed exclusively by non-governmental organizations reached the height of 100 kilometers defined as the boundary to space, without, however, reaching Earth orbit . In July 2005, developer Burt Rutan founded his own private space organization. Starting in 2009, the company Virgin Galactic should offer suborbital flights for around 200,000 US dollars.
  • On September 28, 2008, a Falcon 1 successfully brought a 165 kg payload into a 500 by 700 kilometer high orbit. It is the first private satellite transport with a liquid rocket. The rocket is developed and operated by SpaceX .
  • On November 30th, 2009 the first successful start of an Atea-1 of the New Zealand company Rocket Lab Ltd. It is said to have reached a height of 120 kilometers.
  • During a mission from May 22, 2012 to May 31, the SpaceX Dragon spaceship reached the ISS. The spaceship transported 520 kg of cargo to the ISS and landed back on earth with over 600 kg of equipment that was no longer needed.

Future development

Carrier systems

Combined aircraft and space vehicles or the space elevator should further reduce start-up costs and help space travel to achieve greater economic success. By Nanotechnology has succeeded in new raw materials ( water , aluminum , see ALICE ) to make it usable for the drive, which are available in large quantities and a flight with comparatively harmless allow emissions. Eugen Sanger's vision has so far gone beyond the engineering possibilities : the photon beam drive, with which one could reach other stars and galaxies . In order to be able to cover very long distances (such as the journey to Mars) faster, research is also currently being carried out on the promising EmDrive method , which uses microwaves to generate thrust.

research

The search for life outside the earth ( astrobiology ) has moved more and more into the focus of the arguments in recent years, but basic research will continue to be carried out, for example with the planned James Webb Space Telescope or the Laser Interferometer Space Antenna .

Space tourism

Space tourism refers to pleasure or study trips in suborbital orbit or earth orbit. The current destinations are Earth orbit as a flight event and the International Space Station (ISS) for a visit. The US company Space Adventures plans in cooperation with Russia to offer flights around the moon in the future. In the future, which cannot be determined at present, the company Virgin Galactic also wants to offer suborbital flights with the SpaceShipTwo space aircraft for US $ 200,000 .

Moon base

NASA developed the Ares carrier family as part of the Constellation program . However, this was deleted without replacement by the then US President Barack Obama. The aim was for people to land on the moon again. Instead of just short trips, a moon base was to be built this time. In this way new research fields could have been opened up.

Mars landing

NASA also wants to send people to Mars after 2030. The costs and challenges are much greater than those of a moon flight.

Space hotel

The most advanced project comes from Bigelow Aerospace , which was founded in 1999 by the US American Robert Bigelow , a hotelier and real estate agent. On June 12, 2006, Bigelow Aerospace's first test satellite, called Genesis 1, was launched from Russia to test the technology for it. On June 28, 2007, after several postponements, Genesis 2 was launched with a Dnepr rocket. The idea is to transport residential modules with an inflatable outer skin into space. This is a technology that was originally developed by NASA. After development stopped, Robert Bigelow bought the patent.

Extraction of raw materials

Many asteroids or NEOs contain metals such as platinum, iron, nickel and rare earth metals . The moon has helium-3, which can be used for nuclear fusion. In view of dwindling resources , the extraction of raw materials on foreign celestial bodies could pay off. There are concepts for asteroid mining .

Stanford torus inside

Space colonization

Space colonization is the concept of a human habitat outside the earth and thus a major topic in science fiction , but also a long-term goal of various national space programs. Corresponding colonies could be set up on the surfaces of planets or the moon or inside asteroids. There are also considerations to build large wheels or tubes in space that create artificial gravity through rotation.

Military space travel

The first considerations for orbital weapon systems and the militarization of space existed as early as the 1950s. The space race , the Cold War, and the US and Soviet Union arms race led to military research and development in this area. For armament projects such as SDI (from 1984) and later NMD , space-based weapons technologies were developed and in some cases also tested on a small scale. The Soviet Union developed killer satellites such as B. Poljus (1987) and prototypes of military spacecraft such as Uragan . Both superpowers operated secret research programs for the development Transatmosphärischer aircraft (Engl. Trans-Atmospheric Vehicles- TAV), which would have been able to Low Earth Orbit to achieve. After tests with nuclear weapons such as Starfish Prime (1962) had also been carried out in the exosphere , treaties such as the Treaty on the Prohibition of Nuclear Weapons Tests in the Atmosphere, in Space and Underwater (1963) and the Space Treaty (1967) were concluded. . Technical military reconnaissance, communication, navigation, early detection and surveillance from earth orbit became increasingly important. Today (as of 2011) some nations such as the USA, Russia and China operate military space travel to different degrees. There are concepts for a future planetary defense .

Additional terms

Space agencies (selection)

Europe

Worldwide

Education

For a career in space is course aerospace engineering relevant. It can be studied at universities and technical colleges as a bachelor's , master's and diploma .

See also

Portal: Space  - Overview of Wikipedia content on space travel

literature

History of space travel
Future development
  • Jai Galliott, et al .: Commercial space exploration - ethics, policy and governance. Ashgate, Farnham 2015, ISBN 978-1-4724-3611-5 .
Space technology, space and propulsion systems
  • David Ashford: Spaceflight revolution. Imperial College Press, London 2002, ISBN 1-86094-325-X
  • Paul A. Czysz: Future spacecraft propulsion systems. Springer, Berlin 2006, ISBN 3-540-23161-7
  • Wilfried Ley, Klaus Wittmann, Willi Hallmann: Handbook of space technology. Hanser, Munich 2008, ISBN 3-446-41185-2
  • Ernst Messerschmid, Stefanos Fasoulas: Space systems - an introduction with exercises and solutions. Springer, Berlin 2005, ISBN 3-540-21037-7
  • Martin Tajmar : Advanced space propulsion systems. Springer, Vienna 2003, ISBN 3-211-83862-7
  • Malcolm Macdonald, Viorel Badescu: The International Handbook of Space Technology. Springer, Berlin 2014, ISBN 978-3-662-50608-0 .
Interplanetary and interstellar exploration
  • Paul Gilster: Centauri dreams-imagining and planning interstellar exploration. Springer, New York 2004, ISBN 0-387-00436-X
  • Stephen Kemble: Interplanetary mission analysis and design. Springer, Berlin 2006, ISBN 3-540-29913-0

Web links

Commons : Space  - collection of images, videos and audio files
Wiktionary: Space travel  - explanations of meanings, word origins, synonyms, translations
Wikibooks: The Race to the Moon - The Role of Space Travel in the Cold War  - Learning and teaching materials

Individual evidence

  1. ↑ Nasa wants to do research on the ISS for another four years. Zeit Online, January 8, 2014, accessed May 2, 2018 .
  2. ↑ The life span of ISS could be extended by four years into 2028, the head of Russia's SP Korolev RSC Energia said Tuesday. Sputnik International, November 15, 2016, accessed on May 2, 2018 .
  3. ↑ Chris Keall: NZ rocket blasts off - and so will profits, maker says. National Business Review, December 1, 2009, archived from the original on April 7, 2014 ; accessed on April 6, 2014 .
  4. ↑ COTS-2 Mission Press Kit. (PDF; 6 MB) SpaceX, accessed on May 19, 2012 (English).
  5. ↑ The Role of Near-Earth Asteroids in Long-Term Platinum Supply nss.org (PDF; 75 kB), accessed on March 1, 2011
  6. ^ John S. Lewis: Mining the sky - untold riches from the asteroids, comets, and planets. Addison-Wesley, Reading 1997, ISBN 0-201-32819-4
  7. ↑ Hans Günter Brauch et al .: Military use of space - a bibliography. Berlin-Verl., Berlin 1988, ISBN 3-87061-273-8 .
  8. ↑ Military Space Programs fas.org, accessed 26 December 2011
  9. ↑ Nina-Louisa Remuss: Space and Security , in: Christian Brünner et al .: Outer space in society, politics and law. Springer, Vienna 2011, ISBN 978-3-7091-0663-1 , p. 519 ff.
  10. ↑ Thomas Kretschmer et al .: Military Use of Space - Basics and Options. Report-Verlag, Frankfurt am Main 2004, ISBN 3-932385-18-7 ; Pp. 140 ff., 177 ff.
  11. ↑ Printed matter 15/1371 p. 46, bundestag.de, PDF accessed on January 16, 2012
  12. ↑ Michael E. O'Hanlon: The science of war - defense budgeting, military technology, logistics, and combat outcomes. Princeton Univ. Press, Princeton 2009, ISBN 978-0-691-13702-5 ; The military uses of space; P. 187 ff.
  13. ^ Bert Chapman: Space warfare and defense - a historical encyclopedia and research guide. ABC-CLIO, Santa Barbara 2008, ISBN 978-1-59884-006-3 ; Other countries space weapon programs , p. 183 ff.
  14. ^ Wilfried Ley, Klaus Wittmann, Willi Hallmann: Handbook of space technology. Hanser, Munich 2008, ISBN 3-446-41185-2