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SalyutThe Salyut (Russian: Салют, Salute or Firework) program was a series of space stations launched by the Soviet Union in the 1970s. The Salyuts were all relatively simple structures consisting of a single main module placed into orbit in a single launch. The program was originally designated the DOS 7-K program, with each Salyut station receiving a designation.
orbit booster on the launch pad]]
Salyut 1 (DOS 1) was launched April 19, 1971. It was the first space station ever orbited. Its first crew launched in Soyuz 10 but was unable to board it due to a failure in the docking mechanism; its second crew launched in Soyuz 11 and remained on board for 23 productive days. Unfortunately, a pressure-equalization valve in the Soyuz 11 reentry capsule opened prematurely when the crew returned to Earth, killing all three. Salyut 1 reentered Earth's atmosphere October 11, 1971.
Salyut 2 was launched April 3, 1973. It was not really a part of the same program as the other Salyut stations, instead being the highly classified prototype military space station Almaz. It was given the designation Salyut 2 to conceal its true nature. Despite its successful launch, within two days the as-yet-unmanned Salyut 2 began losing pressure and its flight control failed; the cause of the failure was likely due to shrapnel piercing the station when the discarded Proton rocket upper stage that had placed it in orbit later exploded nearby.
The Salyut space station that Almaz had substituted for, designated DOS 3, was launched on May 11, 1973, three days before the launch of Skylab. Due to errors in the flight control system while out of the range of ground control, the station fired its orbit-correction engines until it consumed all of its fuel. Since the spacecraft was already in orbit and had been registered by Western radar, the Soviets disguised the launch as "Cosmos 557" and quietly allowed it to reenter Earth's atmosphere and burn up a week later. It was revealed to have been a Salyut station only much later.
Salyut 3 was launched on June 25, 1974. It was another Almaz military space station, this one launched successfully. It tested a wide variety of reconnaissance sensors, returning a canister of film for analysis. On January 24, 1975 trials of the on-board 23mm Nudelmann aircraft cannon (other sources say it was a Nudelmann NR-30 30mm gun) were conducted with positive results at ranges from 3000 m to 500 m. Cosmonauts have confirmed that a target satellite was destroyed in the test. The next day, the station was ordered to deorbit. Only one of the three intended crews successfully boarded and manned the station, brought by Soyuz 14; Soyuz 15 attempted to bring a second crew but failed to dock. Nevertheless, Salyut 3 was an overall success.
Salyut 4 (DOS 4) was launched on December 26, 1974. It was essentially a copy of the DOS 3, and unlike its ill-fated sibling it was a complete success. Three crews made stays aboard Salyut 4 (Soyuz 17, Soyuz 18 and Soyuz 21), including one of 63 days duration, and an unmanned Soyuz capsule remained docked to the station for three months, proving the systems' long-term durability. Salyut 4 was deorbited February 3, 1977.
Salyut 5 was launched on June 22, 1976. It was the third and last Almaz military space station. Its launch and subsequent mission were both completed successfully, with three crews launching and two (Soyuz 21 and Soyuz 24) successfully boarding the craft for lengthy stays (the second crew on Soyuz 23 was unable to dock and had to abort). Salyut 5 reentered on August 8, 1977.
Salyut 6 was launched on September 29, 1977. Although it resembled the previous Salyut stations in overall design, it featured several revolutionary advances including a second docking port where an unmanned Progress cargo spacecraft could dock and refuel the station. From 1977 until 1982 Salyut 6 was visited by five long-duration crews and 11 short-term crews, including cosmonauts from Warsaw Pact countries. The very first long-duration crew on Salyut 6 broke a record set onboard Skylab, staying 96 days in orbit. The longest flight onboard Salyut 6 lasted 185 days. The fourth Salyut 6 expedition deployed a 10-meter radio-telescope antenna delivered by a cargo ship. After Salyut 6 manned operations were discontinued in 1981, a heavy unmanned spacecraft called TKS and developed using hardware left from the canceled Almaz program was docked to the station as a hardware test. Salyut 6 was deorbited July 29, 1982.
Salyut 7 was launched on April 19, 1982. It was the back-up vehicle for Salyut 6 and very similar in equipment and capabilities, though several more advanced features were included. It was aloft for four years and two months, during which time it was visited by 10 crews constituting 6 main expeditions and 4 secondary flights (including French and Indian cosmonauts). Aside from the many experiments and observations made on Salyut 7, the station also tested the docking and use of large modules with an orbiting space station. The modules were called "Heavy Cosmos modules." They helped engineers develop technology necessary to build Mir. Salyut 7 deorbited on February 7, 1991.
List of Soviet / Russian space stations
See also
- Salyut 1
- Salyut 2
- Salyut 3
- Salyut 4
- Salyut 5
- Salyut 6
- Salyut 7
- Mir
- Skylab
- International Space Station
- Space station for statistics of occupied space stations
External links
- [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19870012563_1987012563.pdf Soviet Space Stations as Analogs - NASA report (PDF format)]
Category:Salyut programme
ja:サリュート
Space stationA space station is an artificial structure designed for humans to live in outer space. A space station is distinguished from other manned spacecraft by its lack of major propulsion or landing facilities — instead, other vehicles are used as transport to and from the station. Space stations are designed for medium-term living in orbit, for periods of weeks, months, or even years.
Space stations are used to study the effects of long-term space flight on the human body as well as to provide platforms for greater number and length of scientific studies than available on other space vehicles. Since the ill-fated flight of Soyuz 11 to Salyut 1, all manned spaceflight duration records have been set aboard space stations. The duration record of 437.7 days was set by Valeri Polyakov aboard Mir from 1994 to 1995. As of 2005, 3 astronauts have completed single missions of over a year, all aboard Mir.
Past and present space stations
- Salyut stations: Salyut 1, Salyut 2 (failed on-orbit, never occupied), Salyut 3, Salyut 4, Salyut 5, Salyut 6, Salyut 7
- Skylab
- Mir
- International Space Station (ISS)
Following the controlled deorbiting of Mir in 2001, the International Space Station is the only one of these currently in orbit; it has been continuously manned since October 30, 2000.
A second Skylab unit (Skylab B) was manufactured, as a backup article; due to the high costs of providing launch vehicles, and a desire by NASA to cease Saturn & Apollo operations in time to prepare for the Space Shuttle coming into service, it was never flown. The hull can now be seen in the National Air and Space Museum, in Washington DC, where it is a popular tourist attraction. A number of additional Salyuts were also produced, as backups or as flight articles which were later cancelled.
The International Space Station evolved from the American Space Station Freedom program, which - despite being under development for ten years - was never launched; it incorporated elements of a Mir replacement station ("Mir 2") which was also never constructed. Other cancelled space station programs included the United States Air Force Manned Orbiting Laboratory project, cancelled in 1969 about a year before the first planned test flight; this was unusual in being an explicitly military project, as opposed to the Soviet Almaz program, which was heavily intertwined with - and concealed by - the contemporaneous Salyut program.
Currently, Bigelow Aerospace is commercially developing inflatable habitat modules, derived from the earlier Transhab concept, intended to be used for space station construction.
Types of space station
Broadly speaking, the space stations so far launched have been of two types; the earlier stations, Salyut and Skylab, have been "monolithic", intended to be constructed and launched in one piece, and then manned by a crew later. As such, they generally contained all their supplies and experimental equipment when launched, and were considered "expended", and then abandoned, when these were used up.
Starting with Salyut 6 and 7, a change was seen; these were built with two docking ports, which allowed a second crew to visit, bringing a new spacecraft (for technical reasons, a Soyuz capsule cannot spend more than a few months on orbit, even powered down, safely) with them. This allowed for a crew to man the station continually. The presence of a second port also allowed Progress supply vehicles to be docked to the station, meaning that fresh supplies could be brought to aid long-duration missions. This concept was expanded on Salyut 7, which "hard docked" with a TKS tug shortly before it was abandoned; this served as a proof-of-concept for the use of modular space stations. The later Salyuts may reasonably be seen as a transition between the two groups.
The second group, Mir and the ISS, have been modular; a core unit was launched, and additional modules, generally with a specific role, were later added to that. (On Mir they were usually launched independently, whereas on the ISS most are brought by the Shuttle). This method allows for greater flexibility in operation, as well as removing the need for a single immensely powerful launch vehicle. These stations are also designed from the outset to have their supplies provided by logistical support, which allows for a longer lifetime at the cost of requiring regular support launches.
These stations have various issues that limit their long-term habitability, such as very low recycling rates, high radiation levels and a lack of gravity. Some of these problems cause discomfort and long-term health effects. In the case of solar flares, most current habitats even have an acute danger of radiation poisoning. Some space habitats address these issues, and are intended for long-term occupation. Some designs might even accommodate large numbers of people, essentially "cities in space" where people would make their homes. No such design has yet been constructed, because even for a small station, the extra equipment is too expensive to place in orbit at current (2005) launch costs.
List of occupied space stations, with statistics
-
- ISS stats as of August 28, 2005.
-
- ISS stats as of October 6, 2005.
In fiction
A large amount of science fiction is set on space stations. A notable example is Babylon 5, a series set on a space station by that name far into the future. Similarly, Deep Space 9 is a prominent space station in the Star Trek story line. It was built by the Cardassians around Bajor and later staffed by Federation personnel.
The film (and novel) 2001: A Space Odyssey contains a large space station, built as a revolving ring; this has proven to be one of the iconic images of a space station in popular culture.
The James Bond film Moonraker featured a space station which serves as Hugo Drax's lair and a base to nerve-gas Earth.
The Star Wars films A New Hope (Star Wars) and Return of the Jedi each feature a heavily armored space station known as the Death Star, which is capable of destroying a planet. Some may dispute the usage of the term space station to describe the Death Stars because they are capable of traveling great distances.
Category:Space stations
ja:宇宙ステーション
Soviet Union
The Union of Soviet Socialist Republics, abbreviated USSR ( (СССР) ; tr.: Soyuz Sovetskikh Sotsialisticheskikh Respublik [SSSR])), more commonly known as the Soviet Union (; tr.: Sovetsky Soyuz) was an officially socialist state founded in 1922, centered on Russia, and dissolved in 1991. From 1945 until its dissolution it was historically notable as one of the world's two superpowers.
The formation of the Soviet Union was the culmination of the Russian Revolution of 1917, which
overthrew short-lived Provisional Government (established after Tsar Nicholas II abdicated on March 15, 1917), and later the Red Army victory in the violent Russian Civil War from 1918-1920. The geographic boundaries of the Soviet Union varied with time, but by 1945 it approximately corresponded to that of historic Imperial Russia, with the notable exclusions of Poland and Finland. The geographic size of the Soviet Union remained from 1945 until its dissolution.
The Soviet Union, founded three decades before the Cold War, became a primary model for future Communist states; the socialist government and the political organization of the country were defined by the only permitted political party, the Communist Party of the Soviet Union.
History
The Soviet Union is traditionally considered to be the successor of the Russian Empire. The last Russian monarch, Tsar Nicholas II, ruled until March 1917 and was eventually executed. The Soviet Union was established in December 1922 as the union of the Russian, Ukrainian, Belarusian, and Transcaucasian Soviet republics ruled by Bolshevik parties.
By Soviet historiography, revolutionary activity in Russia began with the Decembrist Revolt of 1825, and although serfdom was abolished in 1861, its abolition was achieved on terms unfavorable to the peasants and served to encourage revolutionaries. A parliament, the State Duma, was established in 1906, after the 1905 Revolution but political and social unrest continued and was aggravated during World War I by military defeat and food shortages.
A spontaneous popular uprising in Petrograd, in response to the wartime decay of Russia's physical well-being and morale, culminated in the toppling of the imperial government in March 1917 (see February Revolution). The autocracy was replaced by the Provisional Government, whose leaders intended to establish democracy in Russia and to continue participating on the side of the Allies in World War I. At the same time, to ensure the rights of the working class, workers' councils, known as soviets, sprang up across the country. The radical Bolsheviks, led by Vladimir Ilyich Lenin, agitated for socialist revolution in the soviets and on the streets. They seized power from the Provisional Government in November 1917 (see October Revolution). Only after the long and bloody Russian Civil War of (1918-1921), which included combat between government forces and foreign troops in several parts of Russia, was the new communist regime secure. In a related conflict, the "Peace of Riga" in early 1921 split disputed territories in Belarus and Ukraine between Poland and Soviet powers.
From its first years, government in the Soviet Union was based on the one-party rule of the Communist Party, as the Bolsheviks called themselves beginning in March 1918. After the extraordinary economic policy of war communism during the Civil War the Soviet government permitted some private enterprise to coexist with nationalized industry in the 1920s and total food requisition in the countryside was replaced by a food tax (see New Economic Policy). Debate over the future of the economy provided the background for Soviet leaders to contend for power in the years after Lenin's death in 1924. By gradually consolidating his influence and isolating his rivals within the party, notably Lenin's more obvious heir Leon Trotsky, Joseph Stalin became the sole leader of the Soviet Union by the end of the 1920s.
In 1928 Stalin introduced the First Five-Year Plan for building a socialist economy. In industry the state assumed control over all existing enterprises and undertook an intensive program of industrialization; in agriculture collective farms were established all over the country (see Collectivisation in the USSR). The Soviet Union became a major industrial power; but the plan's implementation produced widespread misery for some segments of the population. Collectivization met widespread resistance from peasants, resulting in a bitter struggle against the authorities in many areas, famine, and estimated millions of casualties. Social upheaval continued in the mid-1930s, when Stalin began a purge of the party (see Great Purges). Yet despite this turmoil, the Soviet Union developed a powerful industrial economy in the years before World War II.
Although Stalin tried to avert war with Germany by concluding the Nazi-Soviet Nonaggression Pact, which involved the invasion of Poland, in 1939, Germany invaded the Soviet Union in 1941. It has been debated that the Soviet Union had the intention of invading Germany once it was strong enough. The Red Army stopped the Nazi offensive, with the Battle of Stalingrad in 1943 being the major turning point, and drove through Eastern Europe to Berlin before Germany surrendered in 1945 (see Great Patriotic War). Although ravaged by the war, the Soviet Union emerged from the conflict as an acknowledged superpower.
superpower after the fall of Nazi Germany]]
During the immediate postwar period, the Soviet Union first rebuilt and then expanded its economy, while maintaining its strictly centralized control. The Soviet Union aided postwar reconstruction in Eastern Europe, set up the Warsaw Pact and Comecon, supplied aid to the eventually victorious communists in the People's Republic of China, and saw its influence grow elsewhere in the world. Meanwhile, the Cold War, turned the Soviet Union's wartime allies, the United Kingdom and the United States, into foes.
Joseph Stalin died on March 5 1953. In the absence of an acceptable successor, the highest Communist Party officials opted to rule the Soviet Union jointly, although a struggle for power took place behind the facade of collective leadership. Nikita Khrushchev, who won the power struggle by the mid-1950s, denounced Stalin's use of repression and eased repressive controls over party and society (see de-Stalinization). During this period the Soviet Union launched the first satellite Sputnik 1 and man Yuri Gagarin into orbit. Khrushchev's reforms in agriculture and administration, however, were generally unproductive, and foreign policy toward China and the United States suffered reverses. Khrushchev's colleagues in the leadership removed him from power in 1964.
Following the ouster of Khrushchev, another period of rule by collective leadership ensued, lasting until Leonid Brezhnev established himself in the early 1970s as the preeminent figure in Soviet political life. Brezhnev presided over a period of Détente with the West while at the same time building up Soviet military strength; the arms buildup contributed to the demise of Détente in the late 1970s. Another contributing factor was the Soviet invasion of Afghanistan in December 1979.
After some experimentation with economic reforms in the mid-1960s, the Soviet leadership reverted to established means of economic management. Industry showed slow but steady gains during the 1970s, while agricultural development continued to lag. Throughout the period the Soviet Union maintained parity with the United States in the areas of military technology but this expansion ultimately crippled the economy. In contrast to the revolutionary spirit that accompanied the birth of the Soviet Union, the prevailing mood of the Soviet leadership at the time of Brezhnev's death in 1982 was one of aversion to change.
Two developments dominated the decade that followed: the increasingly apparent crumbling of the Soviet Union's economic and political structures, and the patchwork attempts at reforms to reverse that process. After the rapid succession of Yuri Andropov and Konstantin Chernenko, transitional figures with deep roots in Brezhnevite tradition, the energetic Mikhail Gorbachev made significant changes in the economy (see Perestroika) and the party leadership. His policy of glasnost freed public access to information after decades of government regulations.
In late 1980s constituent republics of the Soviet Union started declaring sovereignty over their territories or even independence citing Article 72 of USSR Constitution, which stated that any constituent republic was free to secede. Many republics proceeded to produce legislation contradicting the Union laws in what was known as "The War of Laws." In 1989 Russian SFSR, which was then the largest constituent republic (with about 2/3 of population and territory) convened a Congress of Deputies. Boris Yeltsin was elected the chairman of the Congress. On June 12, 1989 the Congress declared Russia's sovereignty over its territory and proceeded to pass laws that attempted to supersede some of the USSR's laws. The period of legal uncertainty continued for the next three years as constituent republics slowly growing de-facto independent.
A referendum for the preservation of the USSR was held on March 17, 1991, with the population voting for preservation of the Union in most republics. The referendum gave Gorbachev a minor boost, and in the summer of 1991 an new Union Treaty was designed and agreed upon by most republics which would have turned the Soviet Union into a much looser federation. The signing of the treaty, however, was interrupted by the August Coup - an attempted coup d'état against Mikhail Gorbachev by conservative members of the Communist Party, referred to as "Hardliners" by the Western media. After the coup was defeated, Yeltsin came out as a hero while Gorbachev's power was greatly reduced. The balance of power tipped significantly towards the republics. Latvia, Estonia and Lithuania were immediately granted independence, while the other 12 republics continued discussing new, increasingly looser, models of the Union. On December 8 1991 Presidents of Russia, Ukraine and Belarus signed Belavezha Accords which declared the Union dissolved and established the Commonwealth of Independent States in its place. While doubts remained over their authority to dissolve the Union, on 25 December 1991, Gorbachev resigned as the president of the USSR and turned the powers of his office over to Boris Yeltsin. The following day, the Supreme Soviet, the highest governmental body of the Soviet Union, dissolved itself. This is generally recognized as the official, final dissolution of the Soviet Union as a functioning nation. Many organizations such as the Red Army and Police forces continued to remain in place in the early months of 1992, but were slowly phased out or absorbed by the newly independent nations.
Politics
Supreme Soviet]
The government of the Soviet Union administered the country's economy and society. It implemented decisions made by the leading political institution in the country, the Communist Party of the Soviet Union (CPSU).
In the late 1980s, the government appeared to have many characteristics in common with democratic political systems. For instance, a constitution established all organs of government and granted to citizens a series of political and civic rights. A legislative body, the Congress of People's Deputies, and its standing legislature, the Supreme Soviet, represented the principle of popular sovereignty. The Supreme Soviet, which had an elected chairman who functioned as head of state, oversaw the Council of Ministers, which acted as the executive branch of the government. The chairman of the Council of Ministers, whose selection was approved by the legislative branch, functioned as head of government. A constitutionally based judicial branch of government included a court system, headed by the Supreme Court, that was responsible for overseeing the observance of Soviet law by government bodies. According to the 1977 Soviet Constitution, the government had a federal structure, permitting the republics some authority over policy implementation and offering the national minorities the appearance of participation in the management of their own affairs.
In practice, however, the government differed markedly from Western systems. In the late 1980s, the CPSU performed many functions that governments of other countries usually perform. For example, the party decided on the policy alternatives that the government ultimately implemented. The government merely ratified the party's decisions to lend them an aura of legitimacy. The CPSU used a variety of mechanisms to ensure that the government adhered to its policies. The party, using its nomenklatura authority, placed its loyalists in leadership positions throughout the government, where they were subject to the norms of democratic centralism. Party bodies closely monitored the actions of government ministries, agencies, and legislative organs.
The content of the Soviet Constitution differed in many ways from typical Western constitutions. It generally described existing political relationships, as determined by the CPSU, rather than prescribing an ideal set of political relationships. The Constitution was long and detailed, giving technical specifications for individual organs of government. The Constitution included political statements, such as foreign policy goals, and provided a theoretical definition of the state within the ideological framework of Marxism-Leninism. The CPSU leadership could radically change the constitution or remake it completely, as it did several times throughout its history.
The Council of Ministers acted as the executive body of the government. Its most important duties lay in the administration of the economy. The council was thoroughly under the control of the CPSU, and its chairman - the Soviet prime minister - was always a member of the Politburo. The council, which in 1989 included more than 100 members, was too large and unwieldy to act as a unified executive body. The council's Presidium, made up of the leading economic administrators and led by the chairman, exercised dominant power within the Council of Ministers.
According to the Constitution, as amended in 1988, the highest legislative body in the Soviet Union was the Congress of People's Deputies, which convened for the first time in May 1989. The main tasks of the congress were the election of the standing legislature, the Supreme Soviet, and the election of the chairman of the Supreme Soviet, who acted as head of state. Theoretically, the Congress of People's Deputies and the Supreme Soviet wielded enormous legislative power. In practice, however, the Congress of People's Deputies met infrequently and only to approve decisions made by the party, the Council of Ministers, and its own Supreme Soviet. The Supreme Soviet, the Presidium of the Supreme Soviet, the chairman of the Supreme Soviet, and the Council of Ministers had substantial authority to enact laws, decrees, resolutions, and orders binding on the population. The Congress of People's Deputies had the authority to ratify these decisions.
The judiciary was not independent. The Supreme Court supervised the lower courts and applied the law, as established by the Constitution or as interpreted by the Supreme Soviet. The Constitutional Oversight Committee reviewed the constitutionality of laws and acts. The Soviet Union lacked an adversarial court procedure known to common law jurisdictions. Rather, Soviet law utilised the system derived from Roman law, where judge, procurator and defense attorney worked collaboratively to establish the truth.
The Soviet Union was a federal state made up of fifteen republics joined together in a theoretically voluntary union. In turn, a series of territorial units made up the republics. The republics also contained jurisdictions intended to protect the interests of national minorities. The republics had their own constitutions, which, along with the all-union Constitution, provide the theoretical division of power in the Soviet Union. In 1989, however, the CPSU and the central government retained all significant authority, setting policies that were executed by republic, provincial, oblast, and district governments.
Leaders of the Soviet Union
The official leader of the Soviet Union was the First/General Secretary of the CPSU. The head of government was considered the Premier, and the head of state was considered the President. The Soviet leader could also have one (or both) of these positions, along with the position of General-Secretary of the party.
:List of Soviet Premiers
:(Chairman of the Council of People's Commissars of the USSR (1923-1946); Chairman of the Council of Ministers of the USSR (1946-1990); Prime Minister of the USSR (1991))
:List of Soviet Presidents
:(Chairman of the Central Executive Committee of the All-Russian Congress of Soviets (1917-1922); Chairman of the Central Executive Committee of the USSR (1922-1938); Chairman of the Presidium of the Supreme Soviet of the USSR (1938-1989); Chairman of the Supreme Soviet of the USSR (1989-1990); President of the Soviet Union (1990-1991))
Foreign relations
:Main article: Foreign relations of the Soviet Union
Foreign relations of the Soviet Union]
Once denied diplomatic recognition by the capitalist world, the Soviet Union had official relations with the majority of the nations of the world by the late 1980s. The Soviet Union also had progressed from being an outsider in international organizations and negotiations to being one of the arbiters of Europe's fate after World War II. A member of the United Nations at its foundation in 1945, the Soviet Union became one of the five permanent members of the UN Security Council which gave it the right to veto any of its resolutions (see Soviet Union and the United Nations).
The Soviet Union emerged from World War II as one of the two major world powers, a position maintained for four decades through its hegemony in Eastern Europe (see Eastern Bloc), military strength, aid to developing countries, and scientific research, especially into space technology and weaponry. The Soviet Union's growing influence abroad in the postwar years helped lead to a socialist system of states in Eastern Europe united by military and economic agreements. Established in 1949 as an economic bloc of communist countries led by Moscow, the Council for Mutual Economic Assistance (COMECON) served as a framework for cooperation among the planned economies of the Soviet Union, and, later, for trade and economic cooperation with the Third World. The military counterpart to the Comecon was the Warsaw Pact. The Soviet economy was also of major importance to Eastern Europe because of imports of vital natural resources from Russia, such as natural gas.
Moscow considered Eastern Europe to be a buffer zone for the forward defense of its western borders and ensured its control of the region by transforming the East European countries into stable allies. Soviet troops intervened in the 1956 Hungarian Revolution and cited the Brezhnev Doctrine, the Soviet counterpart to the U.S. Johnson Doctrine and later Nixon Doctrine, and helped oust the Czechoslovak government in 1968, sometimes referred to as the Prague Spring.
In the late 1950s, a confrontation with China led to the Sino-Soviet split and a tense confrontation between the Soviet Union and the United States over the Soviet deployment of nuclear missiles in Cuba sparked the Cuban Missile Crisis in 1962.
The KGB (Committee for State Security), served in a fashion as the Soviet counterpart to both the FBI and the CIA (Central Intelligence Agency) in the U.S. It ran a massive network of informants throughout the Soviet Union, which was used to monitor violations in law. The foreign wing of the KGB was used to gather intelligence in countries around the globe. After the collapse of the Soviet Union, it was replaced in Russia by the SVR (Foreign Intelligence Service).
The KGB was not without substantial oversight. The GRU (Main Intelligence Directorate), not publicized by Russia until the end of the Soviet era during perestroika, was created by Lenin in 1918 and served both as a centralized handler of military intelligence and as an institutional check-and-balance for the otherwise relatively unrestricted power of the KGB. Effectively, it served to spy on the spies, and, not surprisingly, the KGB served a similar function with the GRU. As with the KGB, the GRU operated in nations around the world, particularly in Soviet bloc and client states. The GRU continues to operate in Russia today, with resources estimated by some to exceed those of the SVR [http://www.fas.org/irp/world/russia/gru/] [http://www.fas.org/irp/world/russia/svr/c103-gb.htm].
military intelligence]]
In the 1970s, the Soviet Union achieved rough nuclear parity with the United States. It perceived its own involvement as essential to the solution of any major international problem. Meanwhile, the Cold War gave way to Détente and a more complicated pattern of international relations in which the world was no longer clearly split into two clearly opposed blocs. Less powerful countries had more room to assert their independence, and the two superpowers were partially able to recognize their common interest in trying to check the further spread and proliferation of nuclear weapons (see SALT I, SALT II, Anti-Ballistic Missile Treaty).
By this time, the Soviet Union had concluded friendship and cooperation treaties with a number of states in the non-communist world, especially among Third World and Non-Aligned Movement states like India and Egypt. Notwithstanding some ideological obstacles, Moscow advanced state interests by gaining military footholds in strategically important areas throughout the Third World. Furthermore, the Soviet Union continued to provide military aid for revolutionary movements in the Third World. For all these reasons, Soviet foreign policy was of major importance to the non-communist world and helped determine the tenor of international relations.
Although myriad bureaucracies were involved in the formation and execution of Soviet foreign policy, the major policy guidelines were determined by the Politburo of the Communist Party. The foremost objectives of Soviet foreign policy had been the maintenance and enhancement of national security and the maintenance of hegemony over Eastern Europe. Relations with the United States and Western Europe were also of major concern to Soviet foreign policy makers, and relations with individual Third World states were at least partly determined by the proximity of each state to the Soviet border and to Soviet estimates of its strategic significance.
When Mikhail Gorbachev succeeded Konstantin Chernenko as General Secretary of the CPSU in 1985, it signalled a dramatic change in Soviet foreign policy. Gorbachev pursued conciliatory policies toward the West instead of maintaining the Cold War status quo. The Soviet Union ended its occupation of Afghanistan, signed strategic arms reduction treaties with the United States, and allowed its allies in Eastern Europe to determine their own affairs.
After the dissolution of the Soviet Union on 25 December, 1991, the Russian Federation claimed to be the legal successor to the Soviet state on the international stage despite its loss of superpower status. Russian foreign policy repudiated Marxism-Leninism as a guide to action, soliciting Western support for capitalist reforms in post-Soviet Russia.
Republics
Russian Federation)]]
The Soviet Union was a federation of Soviet Socialist Republics (SSR). The first Republics were established shortly after the October Revolution of 1917. At that time, republics were technically independent from one another but their governments acted in closely coordinated confederation, as directed by the CPSU leadership. In 1922, four Republics (Russian SFSR, Ukrainian SSR, Belarusian SSR, and Transcaucasian SFSR) joined into the Soviet Union. Between 1922 and 1940, the number of Republics grew to sixteen. Some of the new Republics were formed from territories acquired, or reacquired by the Soviet Union, others by splitting existing Republics into several parts. The criteria for establishing new republics were as follows:
# to be located on the periphery of the Soviet Union so as to be able to exercise their alleged right to secession;
# be economically strong enough to survive on their own upon secession; and
# be named after the dominant ethnic group which should consist of at least one million people.
The system remained almost unchanged after 1940. No new Republics were established. One republic, Karelo-Finnish SSR, was disbanded in 1956. The remaining 15 republics lasted until 1991. Secession remained theoretical, and very unlikely, given Soviet centralism, until the 1991 collapse of the Union. At that time, the republics became independent countries, with some still loosely organized under the heading Commonwealth of Independent States.
Some republics had common history and geographical regions, and were referred by group names. These were Baltic Republics, Transcaucasian Republics, and Central Asian Republics.
In its final state, the Soviet Union consisted of the following republics. (See Republics of the Soviet Union for the list and timeline of other Union republics that existed over time.)
Economy
Republics of the Soviet Union power stations in the Soviet Union]]
Prior to its collapse, the Soviet Union had the largest centrally directed economy in the world. The government established its economic priorities through central planning, a system under which administrative decisions rather than the market determined resource allocation and prices.
Since the Bolshevik Revolution of 1917, the country grew from a largely underdeveloped peasant society with minimal industry to become the second largest industrial power in the world. According to Soviet statistics, the country's share in world industrial production grew from 4 percent to 20 percent between 1913 and 1980. Although many Western analysts considered these claims to be inflated, the Soviet achievement remained remarkable. Recovering from the calamitous events of World War II, the country's economy had maintained a continuous though uneven rate of growth. Living standards, although still modest for most inhabitants by Western standards, had improved.
Although these past achievements were impressive, in the mid-1980s Soviet leaders faced many problems. Production in the consumer and agricultural sectors was often inadequate (see Agriculture of the Soviet Union and shortage economy). Crises in the agricultural sector reaped catastrophic consequences in the 1930s, when collectivization met widespread resistance from the kulaks, resulting in a bitter struggle of many peasants against the authorities, famine, particularly in Ukraine, but also in the Volga River area and Kazakhstan. In the consumer and service sectors, a lack of investment resulted in black markets in some areas.
black market]
In addition, since the 1970s, the growth rate had slowed substantially. Extensive economic development, based on vast inputs of materials and labor, was no longer possible; yet the productivity of Soviet assets remained low compared with other major industrialized countries. Product quality needed improvement. Soviet leaders faced a fundamental dilemma: the strong central controls that had traditionally guided economic development had failed to promote the creativity and productivity urgently needed in a highly developed, modern economy.
Conceding the weaknesses of their past approaches in solving new problems, the leaders of the late 1980s were seeking to mold a program of economic reform to galvanize the economy. The leadership, headed by Mikhail Gorbachev, was experimenting with solutions to economic problems with an openness (glasnost) never before seen in the history of the economy. One method for improving productivity appeared to be a strengthening of the role of market forces. Yet reforms in which market forces assumed a greater role would signify a lessening of authority and control by the planning hierarchy.
Assessing developments in the economy was difficult for Western observers. The country contained enormous economic and regional disparities. Yet analyzing statistical data broken down by region was a cumbersome process. Furthermore, Soviet statistics themselves might have been of limited use to Western analysts because they are not directly comparable with those used in Western countries. The differing statistical concepts, valuations, and procedures used by communist and noncommunist economists made even the most basic data, such as the relative productivity of various sectors, difficult to assess.
Geography
The Soviet Union occupied the eastern portion of the European continent and the northern portion of the Asian continent. Most of the country was north of 50° north latitude and covered a total area of approximately 22,402,200 square kilometres. Due to the sheer size of the state, the climate varied greatly from subtropical and continental to subarctic and polar. 11 percent of the land was arable, 16 percent was meadows and pasture, 41 percent was forest and woodland, and 32 percent was declared "other" (including tundra).
The Soviet Union measured some 10,000 kilometers from Kaliningrad on the Gulf of Gdańsk in the west to Ratmanova Island (Big Diomede Island) in the Bering Strait, or roughly equivalent to the distance from Edinburgh, Scotland, east to Nome, Alaska. From the tip of the Taymyr Peninsula on the Arctic Ocean to the Central Asian town of Kushka near the Afghan border extended almost 5,000 kilometers of mostly rugged, inhospitable terrain. The east-west expanse of the continental United States would easily fit between the northern and southern borders of the Soviet Union at their extremities.
Demographics and society
The Soviet Union was one of the world's most ethnically diverse countries, with more than 150 distinct ethnic groups within its borders. The total population was estimated at 293 million in 1991. The majority of the population were Russians (50.78%), followed by Ukrainians (15.45%) and Uzbeks (5.84%). After all Soviet republics gained independence, Russia remained the largest country in the world by area, and still remains one of the most ethnically diverse.
Nationalities
The extensive multinational empire that the Bolsheviks inherited after their revolution was created by Tsarist expansion over some four centuries. Some nationality groups came into the empire voluntarily, others were brought in by force. Generally, the Russians and most of the non-Russian subjects of the empire shared little in common—culturally, religiously, or linguistically. More often than not, two or more diverse nationalities were collocated on the same territory. Therefore, national antagonisms built up over the years not only against the Russians but often between some of the subject nations as well.
For seventy years, Soviet leaders had maintained that frictions between the many nationalities of the Soviet Union had been eliminated and that the Soviet Union consisted of a family of nations living harmoniously together. However, the national ferment that shook almost every corner of the Soviet Union in the late 1980s proved that seventy years of communist rule had failed to obliterate national and ethnic differences and that traditional cultures and religions would reemerge given the slightest opportunity. This reality facing Gorbachev and his colleagues meant that, short of relying on the traditional use of force, they had to find alternative solutions in order to prevent the disintegration of the Soviet Union.
The concessions granted national cultures and the limited autonomy tolerated in the union republics in the 1920s led to the development of national elites and a heightened sense of national identity. Subsequent repression and Russianization fostered resentment against domination by Moscow and promoted further growth of national consciousness. National feelings were also exacerbated in the Soviet multinational state by increased competition for resources, services, and jobs.
Religious groups
linguistically]]
The state was separated from church by the Decree of Council of People's Comissars 1918 January 23. Official figures on the number of religious believers in the Soviet Union were not available in 1989. But according to various Soviet and Western sources, over one-third of the people in the Soviet Union, an officially atheistic state, professed religious belief. Christianity and Islam had the most believers. Christians belonged to various churches: Orthodox, which had the largest number of followers; Catholic; and Baptist and various other Protestant sects. There were many churches in the country (7500 Russian Orthodox churches in 1974). The majority of the Islamic faithful were Sunni. Although there were many ethnic Jews in the Soviet Union, actual practice of Judaism was rare in Communist times. Jews were the victims of state-sponsored anti-semitism and were one of the few Soviet citizens allowed to emigrate from the country. Other religions, which were practiced by a relatively small number of believers, included Buddhism, Lamaism, and shamanism, a religion based on spiritualism. The role of religion in the daily lives of Soviet citizens varied greatly. Because Islamic religious tenets and social values of Muslims are closely interrelated, religion appeared to have a greater influence on Muslims than on either Christians or other believers. Two-thirds of the Soviet population, however, had no religious beliefs. About half the people, including members of the CPSU and high-level government officials, professed atheism. For the majority of Soviet citizens, therefore, religion seemed irrelevant.
Culture
shamanism]
All media in the Soviet Union were controlled by the state including television and radio broadcasting, newspaper, magazine and book publishing. This extended to the fine arts including the theatre, opera and ballet. Art and Music was controlled by ownership of distribution and performance venues. Censorship was made in cases where performances did not meet with the favour of the Soviet leadership with newspaper campaigns against offending material and sanctions applied though party controlled professional organizations.
- Soviet education
- Soviet cinema
- Soviet television
- USSR at the Summer Olympics
- USSR at the Winter Olympics
- USSR Chess Championship
- Palace of Culture
- Research in the Soviet Union
- Soviet Ballroom dances
- Soviet Student Olympiads
- Great Soviet Encyclopedia
Holidays
Related articles
- Post-Soviet states
- Prometheism
- List of Soviet Leaders
- List of premiers of the Soviet Union
- List of the presidents of the Soviet Union
Further reading
- Brown, Archie, et al, eds.: The Cambridge Encyclopedia of Russia and the Soviet Union (Cambridge, UK: Cambridge University Press, 1982).
- Gilbert, Martin: The Routledge Atlas of Russian History (London: Routledge, 2002).
- Goldman, Minton: The Soviet Union and Eastern Europe (Connecticut: Global Studies, Dushkin Publishing Group, Inc., 1986).
- Howe, G. Melvyn: The Soviet Union: A Geographical Survey 2nd. edn. (Estover, UK: MacDonald and Evans, 1983).
- Katz, Zev, ed.: Handbook of Major Soviet Nationalities (New York: Free Press, 1975).
- Rizzi, Bruno: "The bureaucratization of the world : the first English ed. of the underground Marxist classic that analyzed class exploitation in the USSR" , New York, NY : Free Press, 1985
External links
- [http://www.marxists.org/history/ussr/art/photography/index.htm Images of the Soviet Union] - a collection of photos showing everyday life in the Soviet Union
- [http://geocities.com/deweytextsonline/isr.htm Impressions of Soviet Russia, by John Dewey]
- [http://www.n-wisdom.com/map_volume/world_map/Western_Soviet_Union_map.jpg Map of Western USSR]
- [http://www.angelfire.com/de/Cerskus/english/saitai.html Leonas Cerskus (the highest judge, a God):Crimes against Humanity committed by the Soviet Union]
- [http://koeln.tucker.in/music/gimn_sowjetskowo_sojusa.mp3 Melody of the Soviet National Anthem]
- Vladimir Lenin: What Is Soviet Power? (Text of the speech, )
References
- - [http://lcweb2.loc.gov/frd/cs/sutoc.html Soviet Union]
Category:Communism
Category:Former countries
Category:History of the Soviet Union and Soviet Russia
Category:Former countries in Europe
ko:소비에트 연방
ja:ソビエト連邦
simple:Soviet Union
th:สหภาพโซเวียต
Orbit.]]
:For other meanings of the term "orbit", see orbit (disambiguation)
In physics, an orbit is the path that an object makes around another object while under the influence of a source of centripetal force, such as gravity.
History
Orbits were first analysed mathematically by Johannes Kepler who formulated his results in his laws of planetary motion. He found that the orbits of the planets in our solar system are elliptical, not circular (or epicyclic), as had previously been believed.
Isaac Newton demonstrated that Kepler's laws were derivable from his theory of gravitation and that, in general, the orbits of bodies responding to the force of gravity were conic sections. Newton showed that a pair of bodies follow orbits of dimensions that are in inverse proportion to their masses about their common center of mass. Where one body is much more massive than the other, it is a convenient approximation to take the center of mass as coinciding with the center of the more massive body.
Planetary orbits
Within a planetary system, planets, asteroids, comets and space debris orbit the central star in elliptical orbits. Any comet in a parabolic or hyperbolic orbit about the central star is not gravitationally bound to the star and therefore is not considered part of the star's planetary system. To date, no comet has been observed in our solar system with a distinctly hyperbolic orbit. Bodies which are gravitationally bound to one of the planets in a planetary system, either natural or artificial satellites, follow orbits about that planet.
Due to mutual gravitational perturbations, the eccentricities of the orbits of the planets in our solar system vary over time. Pluto and Mercury have the most eccentric orbits. At the present epoch, Mars has the next largest eccentricity while the smallest eccentricities are those of the orbits of Venus and Neptune.
As an object orbits another, the periapsis is that point at which the two objects are closest to each other and the apoapsis is that point at which they are the farthest from each other.
In the elliptical orbit, the centre of mass of the orbiting-orbited system will sit at one focus of both orbits, with nothing present at the other focus. As a planet approaches periapsis, the planet will increase in velocity. As a planet approaches apoapsis, the planet will decrease in velocity.
See also: Kepler's laws of planetary motion
Understanding orbits
There are a few common ways of understanding orbits.
- As the object moves sideways, it falls toward the orbited object. However it moves so quickly that the curvature of the orbited object will fall away beneath it.
- A force, such as gravity, pulls the object into a curved path as it attempts to fly off in a straight line.
- As the object falls, it moves sideways fast enough (has enough tangential velocity) to miss the orbited object. This understanding is particularly useful for mathematical analysis, because the object's motion can be described as the sum of the three one-dimensional coordinates oscillating around a gravitational center.
As an illustration of the orbit around a planet (eg Earth), the much-used cannon model may prove useful (see image below). Imagine a cannon sitting on top of a (very) tall mountain, which fires a cannonball horizontally. The mountain needs to be very tall, so that the cannon will be above the Earth's atmosphere and we can ignore the effects of air friction on the cannon ball.
300px
If the cannon fires its ball with a low initial velocity, the trajectory of the ball will curve downwards and hit the ground (A). As the firing velocity is increased, the cannonball will hit the ground further (B) and further (C) away from the cannon, because while the ball is still falling towards the ground, the ground is curving away from it (see first point, above). If the cannonball is fired with sufficient velocity, the ground will curve away from the ball at the same rate as the ball falls - it is now in orbit (D). The orbit may be circular like (D) or if the firing velocity is increased even more, the orbit may become more (E) and more (F) elliptical. At a certain even faster velocity (called the escape velocity) the motion changes from an elliptical orbit to a parabola.
Newton's laws of motion
For a system of only two bodies that are only influenced by their mutual gravity, their orbits can be exactly calculated by Newton's laws of motion and gravity. Briefly, the sum of the forces will equal the mass times its acceleration. Gravity is proportional to mass, and falls off proportionally to the square of distance.
To calculate, it is convenient to describe the motion in a coordinate system that is centered on the heavier body, and we can say that the lighter body is in orbit around the heavier body.
An unmoving body that's far from a large object has more energy than one that's close. This is because it can fall farther. This is called "potential energy" because it is not yet actual.
With two bodies, an orbit is a flat curve. The orbit can be open (so the object never returns) or closed (returning), depending on the total kinetic + potential energy of the system. In the case of an open orbit, the speed at any position of the orbit is at least the escape velocity for that position, in the case of a closed orbit, always less.
The path of a free-falling (orbiting) body is always a conic section.
An open orbit has the shape of a hyperbola (or in the limiting case, a parabola); the bodies approach each other for a while, curve around each other around the time of their closest approach, and then separate again forever. This is often the case with comets that occasionally approach the Sun.
A closed orbit has the shape of an ellipse (or in the limiting case, a circle). The point where the orbiting body is closest to Earth is the perigee, called periapsis (less properly, "perifocus" or "pericentron") when the orbit is around a body other than Earth. The point where the satellite is farthest from Earth is called apogee, apoapsis, or sometimes apifocus or apocentron. A line drawn from periapsis to apoapsis is the line-of-apsides. This is the major axis of the ellipse, the line through its longest part.
Orbiting bodies in closed orbits repeat their path after a constant period of time. This motion is described by the empirical laws of Kepler, which can be mathematically derived from Newton's laws. These can be
formulated as follows:
# The orbit of a planet around the Sun is an ellipse, with the Sun in one of the focal points of the ellipse. Therefore the orbit lies in a plane, called the orbital plane. The point on the orbit closest to the attracting body is the periapsis. The point farthest from the attracting body is called the apoapsis. There are also specific terms for orbits around particular bodies; things orbiting the Sun have a perihelion and aphelion, things orbiting the Earth have a perigee and apogee, and things orbiting the Moon have a perilune and apolune (or, synonymously, periselene and aposelene). An orbit around any star, not just the Sun, has a periastron and an apastron
# As the planet moves around its orbit during a fixed amount of time, the line from Sun to planet sweeps a constant area of the orbital plane, regardless of which part of its orbit the planet traces during that period of time. This means that the planet moves faster near its perihelion than near its aphelion, because at the smaller distance it needs to trace a greater arc to cover the same area. This law is usually stated as "equal areas in equal time."
# For each planet, the ratio of the 3rd power of its semi-major axis to the 2nd power of its period is the same constant value for all planets.
Except for special cases like Lagrangian points, no method is known to solve the equations of motion for a system with four or more bodies. The 2-body solutions were published by Newton in Principia in 1687. In 1912, K. F. Sundman developed a converging infinite series that solves the 3-body problem, however it converges too slowly to be of much use.
Instead, orbits can be approximated with arbitrarily high accuracy. These approximations take two forms.
One form takes the pure elliptic motion as a basis, and adds perturbation terms to account for the gravitational influence of multiple bodies. This is convenient for calculating the positions of astronomical bodies. The equations of motion of the moon, planets and other bodies are known with great accuracy, and are used to generate tables for celestial navigation.
The differential equation form is used for scientific or mission-planning purposes. According to Newton's laws, the sum of all the forces will equal the mass times its acceleration (F = ma). Therefore accelerations can be expressed in terms of positions. The perturbation terms are much easier to describe in this form. Predicting subsequent positions and velocities from initial ones corresponds to solving an initial value problem. Numerical methods calculate the positions and velocities of the objects a tiny time in the future, then repeat this. However, tiny arithmetic errors from the limited accuracy of a computer's math accumulate, limiting the accuracy of this approach.
Differential simulations with large numbers of objects perform the calculations in a hierarchical pairwise fashion between centers of mass. Using this scheme, galaxies, star clusters and other large objects have been simulated.
Analysis of orbital motion
(see also orbit equation and Kepler's first law)
To analyse the motion of a body moving under the influence of a force which is always directed towards a fixed point, it is convenient to use polar coordinates with the origin coinciding with the centre of force. In such coordinates the radial and transverse components of the acceleration are, respectively:
:
and
:.
Since the force is always radial, the transverse acceleration is zero, and it follows that:
:,
where h is a constant of integration and we have introduced the auxiliary variable u defined as 1/r. If magnitude of the radial force is f(r) per unit mass of the orbiting body, then the elimination of the time variable from the radial component of the equation of motion yields:
:.
In the case of an inverse square force law the right hand side of the equation becomes a constant and the equation is seen to be the harmonic equation (up to a shift of origin of the dependent variable).
The equation of the orbit described by the particle is thus:
:,
where φ and e are constants of integration and L is the Semi-latus rectum. This can be recognised as the equation of a conic section in polar coordinates.
Orbital parameters
See: Orbital elements
For a general elliptic orbit, the relations between the axis, eccentricity, and least and largest distance are:
:Semimajor axis = (periapsis + apoapsis)/2 = mean of the extreme radii
:Periapsis = semimajor axis × (1 - eccentricity) = least distance
:Apoapsis = semimajor axis × (1 + eccentricity) = largest distance
Note that there are alternative definitions for a "mean radius" or "average distance": if you average the radius over time for one orbit (mean anomaly), or over the orbital angle as observed by the primary (true anomaly), then you get a different result. See here for details.
Orbital period
See: orbital period
Orbital decay
If some part of a body's orbit enters an atmosphere, its orbit can decay because of drag. At each periapsis, the object scrapes the air, losing energy. Each time, the orbit grows less eccentric (more circular) because the object loses kinetic energy precisely when that energy is at its maximum. Eventually, the orbit circularises and then the object spirals into the atmosphere.
The bounds of an atmosphere vary wildly. During solar maxima, the Earth's atmosphere causes drag up to a hundred kilometres higher than during solar minimums.
Some satellites with long conductive tethers can also decay because of electromagnetic drag from the Earth's magnetic field. Basically, the wire cuts the magnetic field, and acts as a generator. The wire moves electrons from the near vacuum on one end to the near-vacuum on the other end. The orbital energy is converted to heat in the wire.
Another method of artificially influencing an orbit is through the use of solar sails or magnetic sails. These forms of propulsion require no propellant or energy input, and so can be used indefinitely. See statite for one such proposed use.
Orbital decay can also occur due to tidal forces for objects below the synchronous orbit for the body they're orbiting. The gravity of the orbiting object raises tidal bulges in the primary, and since below the synchronous orbit the orbiting object is moving faster than the body's surface the bulges lag a short angle behind it. The gravity of the bulges is slightly off of the primary-satellite axis and thus has a component along the satellite's motion. The near bulge slows the object more than the far bulge speeds it up, and as a result the orbit decays. Conversely, the gravity of the satellite on the bulges applies torque on the primary and speeds up its rotation. Artificial satellites are too small to have an appreciable tidal effect on the planets they orbit, but several moons in the solar system are undergoing orbital decay by this mechanism. Mars' innermost moon Phobos is a prime example, and is expected to either impact Mars' surface or break up into a ring within 50 million years.
Finally, orbits can decay via the emission of gravitational waves. This mechanism is extremely weak for most stellar objects, only becoming significant in cases where there is a combination of extreme mass and extreme acceleration, such as with black holes or neutron stars that are orbiting each other closely.
Earth orbits
See Earth orbit for more details.
- Low Earth orbit
- High Earth Orbit
- Intermediate circular orbit
- Geostationary orbit
- Geosynchronous orbit
- Geostationary transfer orbit
- Molniya orbit
- Polar orbit
- Polar Sun Synchronous Orbit
(this is not a complete list).
Scaling in gravity
The gravitational constant G is defined to be:
- 6.6742 × 10−11 N·m2/kg2
- 6.6742 × 10−11 m3/(kg·s2)
- 6.6742 × 10−11(kg/m3)-1s-2.
Thus the constant has dimension density-1 time-2. This corresponds to the following properties.
Scaling of distances (including sizes of bodies, while keeping the densities the same) gives similar orbits without scaling the time: if for example distances are halved, masses are divided by 8, gravitational forces by 16 and gravitational accelerations by 2. Hence orbital periods remain the same. Similarly, when an object is dropped from a tower, the time it takes to fall to the ground remains the same with a scale model of the tower on a scale model of the earth.
When all densities are multiplied by four, orbits are the same, but with orbital velocities doubled.
When all densities are multiplied by four, and all sizes are halved, orbits are similar, with the same orbital velocities.
These properties are illustrated in the formula
:
for an elliptical orbit with semi-major axis a, of a small body around a spherical body with radius r and average density σ, where T is the orbital period.
Role in the evolution of atomic theory
When atomic structure was first probed experimentally early in the twentieth century, an early picture of the atom portrayed it as a miniature solar system bound by the coulomb force rather than by gravity. This was inconsistent with electrodynamics and the model was progressively refined as quantum theory evolved, but there is a legacy of the picture in the term orbital for the wave function of an energetically bound electron state.
See also
- Astrojax
- Circular orbit
- Clarke orbit
- Difference between sub-orbital and orbital spaceflights
- Elliptic orbit
- Escape velocity
- Gravitational slingshot
- Hohmann transfer orbit
- Hyperbolic trajectory
- Kepler's laws of planetary motion
- Orbit equation
- Orbital maneuver
- Orbital period
- Orbital spaceflight
- Orbital speed
- Parabolic trajectory
- Retrograde motion
- Specific orbital energy
- Sub-orbital spaceflight
- Trajectory
External links
- An on-line orbit plotter: http://www.bridgewater.edu/departments/physics/ISAW/PlanetOrbit.html
- [http://www.braeunig.us/space/orbmech.htm Orbital Mechanics] (Rocket and Space Technology)
Category:Celestial mechanics
Category:Solar System
als:Umlaufbahn
ja:軌道 (力学)
simple:Orbit
th:วงโคจร
Launch pad:"Launchpad" redirects here. For the Disney character, see Launchpad McQuack. For the open source project see Launchpad (website)
A launch pad is designed and built to meet a launch vehicle's special needs and requirements. For example:
Most cryogenic launch vehicles need to be continuously topped off as scheduled liftoff approaches. This is particularly necessary as various holds are placed on the liftoff and then removed as support personnel correct problems or verify they are not serious. Without the ability to top off the launch vehicle, the launch would have to be scrubbed when problems slowed down the countdown. Gantrys are commonly designed and constructed on launch pads to meet these types of servicing requirements both during launch and in the preparation period leading up to it.
Most rockets need stable support for a few seconds after ignition while the engines ramp up and stabilize at full thrust. This stability requirement is commonly met by the use of exploding bolts to connect the launch vehicle to the pad. When the vehicle is stable and ready to fly the bolts explode, severing the vehicle's ties to the launch pad and structures on the ground.
Category:Space launch vehicles
Salyut 1
Salyut 1 (DOS 1) was the first Salyut space station, and the first human-made space station of any kind. It was launched April 19, 1971. Its first crew launched in Soyuz 10 but was unable to board it due to a failure in the docking mechanism; its second crew launched in Soyuz 11 and remained on board for 23 productive days. Unfortunately, a pressure-equalization valve in the Soyuz 11 reentry capsule opened prematurely when the crew returned to Earth, killing all three. Salyut 1 reentered Earth's atmosphere October 11, 1971.
Specifications
- Length - 15.8 m
- Maximum diameter - 4.15 m
- Habitable volume - 90 m³
- Weight at launch - 18,900 kg
- Launch vehicle - Proton (three-stage)
- Span across solar arrays - about 10 m
- Area of solar arrays - 28 m²
- Number of solar arrays - 4
- Resupply carriers - Salyut 1-type Soyuz
- Number of docking ports - 1
- Total manned missions - 2
- Total long-duration manned missions - 1
Visiting spacecraft and crews
- Soyuz 10 - April 23–April 25, 1971 - Failed Docking
- Vladimir Shatalov
- Aleksei Yeliseyev
- Nikolai Rukavishnikov
- Soyuz 11 - June 6–June 29, 1971 - Crew died on reentry
- Georgi Dobrovolski
- Viktor Patsayev
- Vladislav Volkov
Structure
Vladislav Volkov
At launch, the announced purpose of Salyut was to test the elements of the systems of a space station and to conduct scientific research and experiments. The craft was described as being 20 m in length, 4 m in maximum diameter, and 99 m³ in interior space with an on-orbit dry mass of 18,425 kg. Of its several compartments, three were pressurized (100 m³ total), and two could be entered by the crew. The first, or transfer, compartment was connected directly with Soyuz 11. Its docking cone had a 2 m front end diameter and a 3 m aft end diameter. The second, and main, compartment was about 4 m in diameter. Televised views showed enough space for eight big chairs (seven at work consoles), several control panels, and 20 portholes (some unobstructed by instruments). The third pressurized compartment contained the control and communications equipment, the power supply, the life support system, and other auxiliary equipment. The fourth, and final, compartment (unpressurized) was about 2 m in diameter and contained the engine installations and associated control equipment. Salyut had buffer chemical batteries, reserve supplies of oxygen and water, and regeneration systems. Externally mounted were two double sets of solar cell panels that extended like wings from the smaller compartments at each end, the heat regulation system's radiators, and orientation and control devices.
Salyut 1 Expeditions
__NOTOC__
Crews and missions
After taking 24 h for rendezvous and approach, Soyuz 10 docked with Salyut on April 23 and remained docked for 5.5 h. The crew did not transfer to the space station. Soyuz 11 required 3 h 19 min on June 7 to complete docking. The crew transferred to Salyut and their mission was announced as
# checking and testing the design, units, onboard systems, and equipment of the orbital piloted station
# trying out the methods and autonomous means of the station's orientation and navigation, as well as the systems for controlling the space complex while maneuvering in orbit
# studying geological-geographical objects on Earth's surface, atmospheric formations, and the snow and ice cover of Earth
# studying physical characteristics, processes, and phenomena in the atmosphere and outer space in various ranges of the spectrum of electromagnetic radiation, and
#conducting medico-biological studies to determine the possibilities of performing various jobs by the cosmonauts in the station and study the influence of space flight factors on the human organism.
On June 29, after flying 362 orbits docked with Salyut, the Soyuz 11 crew transferred back to Soyuz 11. Salyut was moved to higher orbits in July and August of 1971 to ensure that it would not end through early orbital decay. On October 11, the Salyut engines were fired, for the last time, to lower its orbit and ensure prompt decay over the Pacific Ocean. After 175 days in space, the first real space station died. Pravda (October 26, 1971) reported that the Salyut tasks were carried out in 75 percent of the cases by optical means, in 20 percent by radio-technical means, and the small balance by magneto-metrical, gravitational, and other studies. Synoptic readings were taken in both the visible and invisible parts of the electromagnetic spectrum.
See also
- Space station for statistics of occupied space stations
- Salyut
- Mir
- Skylab
- International Space Station
References
- http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=1971-032A
- [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19870012563_1987012563.pdf Soviet Space Stations as Analogs - NASA report (PDF format)]
Category:Salyut programme
Category:Space stations
April 19
April 19 is the 109th day of the year in the Gregorian calendar (110th in leap years). There are 256 days remaining.
Events
- 1012 - Martyrdom of St Alphege in Greenwich, London.
- 1529 - At the Diet of Speyer, a group of rulers (German: Fürst) and independent cities (German: Reichsstadt) protests the reinstatement of the Edict of Worms, beginning the Protestant movement.
- 1587 - Sir Francis Drake sinks the French fleet in Cádiz Harbor.
- 1692 - Bridget Bishop's (in Salem, MA--accused of being a witch) trial.
- 1713 - With no living male heirs, Emperor Charles VI issues the Pragmatic Sanction to ensure that Habsburg lands and the Austrian throne would be inherited by his daughter, Maria Theresa.
- 1775 - American Revolutionary War: The Battle of Lexington and Concord – British General Thomas Gage attempts to confiscate American colonists' firearms. Captain John Parker orders his band of minutemen to not fire unless fired upon. Random shots rang out among the British soldiers. The minutemen promptly fired back. This was the "shot heard round the world." The British are driven back to Boston, Massachusetts, thus beginning the American Revolutionary War.
- 1809 - The army of Austria attacks and is defeated by the forces of the Duchy of Warsaw in the Battle of Raszyn, part of the struggles of the Fifth Coalition.
- 1810 - Venezuela achieves home rule: Emparan, Governor of the Captaincy General is removed by the people of Caracas and a Junta is installed.
- 1839 - The Treaty of London establishes Belgium as a kingdom.
- 1861 - American Civil War: A pro-Secession mob in Baltimore, Maryland, attacks United States Army troops marching through the city.
- 1892 - Charles Duryea claims to have driven the first automobile in the United States, in Springfield, Massachusetts.
- 1904 - Much of Toronto, Ontario, Canada, is destroyed by fire.
- 1909 - Joan of Arc receives beatification.
- 1919 - Leslie Irvin of the United States makes the first successful parachute jump and free fall.
- 1927 - Mae West is sentenced to 10 days in jail for obscenity for her play Sex.
- 1928 - The 125th and final fascicle of the Oxford English Dictionary is published.
- 1933 - President Franklin D. Roosevelt announces that the United States will be abandoning the gold standard.
- 1934 - Shirley Temple debuts in Stand Up and Cheer.
- 1938 - RCA–NBC begins regular television broadcasts.
- 1943 - World War II: In Poland, German troops enter the Warsaw ghetto to round up the remaining Jews, beginning the Warsaw Ghetto Uprising.
- 1943 - Bicycle Day – Swiss chemist Dr. Albert Hofmann deliberately takes LSD for the first time.
- 1950 - Argentina becomes a signatory to the Buenos Aires copyright treaty.
- 1951 - General Douglas MacArthur retires from the military.
- 1956 - Actress Grace Kelly marries Rainier III of Monaco.
- 1960 - Students in South Korea hold a nationwide pro-democracy protest against their president Syngman Rhee, eventually forcing him to resign.
- 1961 - The Bay of Pigs invasion of Cuba ends in failure.
- 1971 - Sierra Leone becomes a republic, and Siaka Stevens the president.
- 1971 - Vietnam War: Vietnam Veterans Against the War begin a five-day demonstration in Washington, DC.
- 1971 - Charles Manson is sentenced to life in prison for the Sharon Tate murders.
- 1971 - Launch of Salyut 1, first human-made space station.
- 1978 - Lagumot Harris is elected President of Nauru.
- 1980 - In The Hague, Netherlands, Johnny Logan wins the twenty-fifth Eurovision Song Contest for Ireland singing "What's Another Year".
- 1989 - A gun turret explodes on the USS Iowa, killing 47 sailors.
- 1989 - Trisha Meili, the "Central Park Jogger" is raped.
- 1993 - The 50-day siege of the Branch Davidian building outside Waco, Texas, USA, ends when a fire breaks out. Eighty-one people die.
- 1995 - Oklahoma City bombing: The Alfred P. Murrah Federal Building in Oklahoma City, Oklahoma, USA, is bombed, killing 168.
- 1999 - The German Bundestag returns to Berlin.
- 2000 - An Air Philippines Boeing 737-200 crashes near Davao International Airport, killing 131.
- 2005 - Joseph Ratzinger elected Pope Benedict XVI on the second day of the Papal conclave.
Births
- 1320 - King Peter I of Portugal (d. 1367)
- 1452 - King Ferdinand II of Aragon (d. 1504)
- 1603 - Michel le Tellier, French statesman (d. 1685)
- 1658 - Johann Wilhelm, Elector Palatine (d. 1716)
- 1665 - Jacques Lelong, French bibliographer (d. 1721)
- 1686 - Vasily Tatishchev, Russian statesman (d. 1750)
- 1721 - Thomas McKean, signer of the U.S. Declaration of Independence (d. 1817)
- 1721 - Roger Sherman, signer of the U.S. Declaration of Independence (d. 1793)
- 1785 - Alexandre Pierre François Boëly, French composer (d. 1858)
- 1793 - Emperor Ferdinand I of Austria (d. 1875)
- 1832 - José Echegaray y Eizaguirre, Spanish writer, Nobel Prize laureate (d. 1916)
- 1874 - Ernst Rüdin, Swiss psychiatrist, geneticist, and eugenicist (d. 1952)
- 1882 - Getúlio Vargas, President of Brazil (d. 1954)
- 1883 - Richard von Mises, Austrian-born mathematician (d. 1953)
- 1892 - Germaine Tailleferre, French composer (d. 1983)
- 1897 - Peter de Noronha, Indian businessman and philanthropist (d. 1970)
- 1897 - Constance Talmadge, American actress (d. 1973)
- 1899 - George O'Brien, American actor (d. 1985)
- 1900 - Richard Hughes, English novelist (d. 1976)
- 1903 - Eliot Ness, American lawman (d. 1957)
- 1912 - Glenn Seaborg, American chemist, Nobel Prize laureate (d. 1999)
- 1919 - Merce Cunningham, American dancer and choreographher
- 1922 - Erich Hartmann, German pilot (d. 1993)
- 1925 - Hugh O'Brian, American actor
- 1928 - Alexis Korner, English musician (d. 1984)
- 1930 - | | |
