As the decade of the 1950s opened, war erupted on the Korean peninsula, which had been split in the aftermath of the Second World War at the 38th Parallel. On 25 June 1950, the army of the communist North Korea crossed the border into South Korea. United States President Harry Truman interrupted a long weekend at his home in Independence, Missouri, to return to the capitol, where, five days later, he authorized General Douglas MacArthur to lead American ground forces to repel the invasion. Also in 1950, Senator Joseph McCarthy of Wisconsin accused State Department employees and many members of the American literary, film, and theatrical communities of being members of the Communist Party. The U.S. Atomic Energy Commission constructed the first nuclear reactor for power production, and in late November, the Chinese entered the Korean War and mounted a counteroffensive into South Korea. MacArthur, famous for his outspoken political views, blatantly violated military regulations by publicly criticizing the president's decisions regarding the conduct of the war, and his conduct had actively interfered in Truman's own attempts to keep the Chinese out of the war. MacArthur, who had been criticized for directing the war from Tokyo without ever having actually stepped foot on the Korean Peninsula, sent a letter to Representative Joe Martin of Massachusetts, the House Minority Leader, openly disagreeing with Truman's policy of limiting the Korean War to avoid a larger war with China. He also sent an ultimatum to the Chinese Army which derailed Truman's efforts to reach a cease-fire with the Chinese. On 11 April 1951, Truman was forced to relieve MacArthur of his command. Also in 1951, the 22nd Amendment to the U.S. Constitution was ratified by Congress, limiting the president to a total of two terms in office; the amendment was driven largely by Republicans who were upset by the dominance of the presidency by Franklin Roosevelt for four terms, then succeeded by Truman, who was in his second. Julius and Ethel Rosenberg were found guilty of selling atomic secrets to the Soviets; they would be executed for treason two years later. Truce negotiations began in Korea in 1951, marred by lengthy delays and bad faith on both sides. Meanwhile, John Mauchly and John Eckert, creaters of ENIAC and BINAC, created UNIVAC I, the first commercial electronic computer, which stored data on magnetic tape. The U.S. Census Bureau would soon install the first UNIVAC I. By 1952, the war continued to rage in Korea. CBS relied on a UNIVAC computer to predict the results of the presidential election; it correctly predicted a landslide victory by former General Dwight D. "Ike" Eisenhower, one of the heroes of World War II. As the United States developed the first hydrogen bomb and elected Eisenhower, the first superhumans began to appear. Many of them were American soldiers serving in Korea, and they were pulled from their units in an effort to develop them into a special operations force, called Team Liberty by the press. Unfortunately, by the time they were ready for deployment, an armistice was signed, bringing an end to hostilities on 27 July 1953. The truce was unsatisfactory to everyone involved; no borders changed, and the peninsula remained divided roughly along the 38th Parallel. Within six months, Team Liberty was disbanded as its members returned to their pre-military lives. Also in 1953, Soviet Premier Josef Stalin died and was succeeded by Nikita Khrushchev, and the Soviet Union followed the United States in developing a hydrogen bomb of its own. The first IBM computer, the IBM 701, was introduced in 1953, and the first high-speed printer was linked to a computer. American researcher James Watson and his English partner, Francis Crick, identified the basic double helix structure of DNA and its self-replicating process; the discovery began a new era in the study of genetics and shed new light on the emerging superhuman population. In response to the appearance of superhumans, the American, British, and Soviet governments independently established programs to study the phenomenon among their populations and to assess any potential threats to their national security that may have resulted . In 1954, Vietnam was divided by the Geneva Agreements when the French were forced out, dividing the former colony into the countries of North Vietnam, South Vietnam, Laos and Cambodia. North Vietnam, like North Korea, was backed by the Soviet Union, while South Vietnam was supported by the United States. Meanwhile, the first superheroes began appearing, starting in New York City with Alexander Stevens, who had served in Korea and was part of the original Team Liberty. Stevens operated as the costumed crimefighter Nucleus, and was soon joined by fellow New Yorker and former Team Liberty teammate Jeff Simonson, who took the name Strongman. The Soviet Union again rejected German unification, heightening Cold War tensions, and Congress censured Senator McCarthy for his behavior during hearings conducted by his Subcommittee on Investigations of the Senate Committee on Governmental Operations. In the landmark case Brown v. Board of Education of Topeka, Kansas, the Supreme Court unanimously overruled the 1896 Plessy v. Ferguson decision and declared that segregated public schools violate the equal protection clause of the 14th Amendment, stating: “We conclude that in the field of education the doctrine of 'separate but equal' has no place. Separate educational facilities are inherently unequal.” Also that year, Microbiologist Jonas Salk's polio vaccine began testing in mass trials, and the first successful kidney transplant was performed by a Harvard University surgical team. The U.S.S. Nautilus, the first nuclear-powered submarine, was launched at Groton, Connecticut, and by order of President Eisenhower, the words “under God” were added to the Pledge of Allegiance. Also in 1954, a Mars "expedition" took 20 thousand photographs of the Red Planet via telescope, apparently confirming the claims of Percival Lowell in 1915 that "Mars is inhabited, and we have absolute proof." Lowell, who dubbed lines seen crossing Mars "canali," or channels—which was frequently misinterpreted as canals—believed them to be proof of extraterrestrial life. The new photographs seemed to support the belief that the canali were of artificial origin, as they followed great-circle courses and one was even observed to be perfectly straight for 1500 miles. Also photographed was a cloud-like formation 1100 miles across in a shape resembling the letter M, which remained in a fixed position for more than a month. At the intersecting points of the shape were three intense bright "knobs;" the cause of the phenomenon was never adequately explained. In 1955, Salk's polio vaccine was pronounced safe, and distributed in a mass immunization program that would eventually wipe out the disease and the fear that accompanied it. Physicists Owen Chamberlain and Emilio Segre discovered the antiproton, a subatomic particle of antimatter identical to the proton but with a negative, rather than positive, charge, while physicists Clyde Cowen, Jr., and Frederick Reines discovered the neutrino, a subatomic particle with no mass or charge. That year, IBM introduced its first business computer, the IBM 752, and the Reverend Martin Luther King, Jr., led the Montgomery bus boycott, the first battle of the modern civil rights struggle. The election of 1956 saw President Eisenhower reelected to his second term. Bolstered by the successful test of the hydrogen bomb and a growing population of superhumans, and equally worried about the U.S.S.R.'s subsequent successful test and its own burgeoning superhuman population, Secretary of State John Foster Dulles employed an aggressively anti-Communist foreign policy. Also in 1956, an IBM team led by John Backus invented FORTRAN, the first computer programming language. In 1957, the United Kingdom joined the United States and the Soviet Union in the exclusive nuclear club when it detonated a hydrogen bomb of its own. Electricity was produced by a nuclear reactor on an experimental basis in Shippingport, Pennsylvania, in 1957. On 4 October of that year, the Soviets placed the first artificial satellite, Sputnik 1, into orbit, and then on 3 November launched Sputnik 2, carrying a dog, Laika (“Barker” in Russian), connected to a life support system. The dog captured hearts around the planet as its life slipped away after a few days in orbit. Sputnik 2 would burn up in the atmosphere on 14 April 1958, five months later. Three months after the launch of Sputnik 1, on 31 January 1958, the United States followed suit by launching the Explorer 1 into orbit as well. The Space Race had begun. On 29 July, the National Aeronautics and Space Act created the National Aeronautics and Space Administration (NASA), which was established on 1 October that year to conduct research and space exploration, despite oppostion from the Department of Defense, which sought to keep space research a military matter. During the opposition of Mars in 1958, Dr. William Sinton performed infrared scans of the planet, and discovered that the sun's energy was being absorbed in certain wavelengths over dark areas near the planet's equator, but not over the lighter desert regions. These wavelengths were the same as those absorbed by hydrocarbon compounds in terrestrial vegetation. Combined with the 1926 discovery that these areas, including Mare Serpentis, Mare Sirenium and Syrtis Major, changed from brown to dark green and back again as Mars' seasons progressed, this led to increased speculation about the possibility of life on Mars, speculation no doubt aided by the growing number of science fiction films featuring alien invaders produced by Hollywood during the 1950s. On 2 January 1959, the U.S.S.R. succeeded in sending an unmanned probe, Luna 1, to the moon after multiple failures by both the Soviets and the Americans. Luna 1 flew within 3,500 miles of the Moon, then went into orbit of the Sun. On 27 April that year, NASA selected its first class of astronauts, known as the Mercury Seven: Malcolm Scott Carpenter, Leroy Gordon “Gordo” Cooper, Jr., John Herschel Glenn, Jr., Virgil Ivan “Gus” Grissom, Walter Marty “Wally” Schirra, Jr., Alan Bartlett Shepard, Jr., and Donald Kent “Deke” Slayton. The astronauts and their wives became media stars after they signed a deal giving Life Magazine the rights to their stories. Cuba, Fidel Castro staged a successful coup against the government of Fulgencio Batista. The new Castro regime accepted aid from the U.S.S.R. and Castro announced that he would export his revolution throughout Central America. Jack Kilby and Robert Noyce independently invented the microchip in 1959, paving the way for miniature products and electronics.