Andrei Dmitrievich Sakharov

At dawn on August 12, 1953, the first Soviet hydrogen bomb, RDS-6s, flashed over the Semipalatinsk test site in Kazakhstan. The core idea of the so-called "sloika" (layer cake) design, alternating fission material and fusion fuel, came from a thirty-two-year-old physicist, Andrei Sakharov. He had worked on thermonuclear theory since joining Igor Tamm's group in 1948, and shortly after the test he was elected a full member of the Academy of Sciences, among the youngest in its history.

In an era when the United States had displayed its nuclear monopoly at Hiroshima and Nagasaki, the Soviet hydrogen bomb ended the age of one-sided nuclear threat and established strategic balance. Sakharov himself understood the work at the time as labor in defense of peace, and he remained at the center of design through the 1955 test of the two-stage thermonuclear device RDS-37. The state made him a Hero of Socialist Labour three times.

Yet those very tests led him elsewhere. In the late 1950s he published calculations showing that radioactive fallout from atmospheric testing inflicted cumulative, no-threshold harm on the world's population, and in 1961 he clashed openly with Khrushchev over the resumption of giant test explosions. The 1963 Moscow treaty banning tests in the atmosphere, underwater, and in space owed something to the persistent objections of Sakharov, a man who had conducted the tests himself. The hands that built the weapon helped bind it.

Sakharov's turn was not an overnight conversion but a gradual passage of twenty years. From the late 1950s he calculated that fallout from atmospheric tests would take hundreds of thousands of lives, and pressed the leadership to halt them. In 1961 he opposed the giant hydrogen-bomb test to Khrushchev's face and was publicly rebuked. His stubborn persuasion is credited with a part in the Partial Test Ban Treaty of 1963.

In 1968 he wrote Reflections on Progress, Peaceful Coexistence and Intellectual Freedom, arguing that before the danger of nuclear war the two systems must converge, and that without intellectual freedom no progress was possible. When the samizdat text was printed in full by the New York Times, the authorities barred him from all secret work. The scientist at the summit of privilege walked into the middle of the human-rights movement.

In 1970 he co-founded the Human Rights Committee and protested by appearing at the trials of political prisoners. In 1975 he became the first Soviet citizen to win the Nobel Peace Prize; forbidden to travel, he was represented by his wife Yelena Bonner, who read the lecture in his stead. The name the conscience of the nation attached itself to him in these years.

When Soviet troops entered Afghanistan in December 1979, Sakharov condemned the invasion publicly to the foreign press. In January he was banished, by administrative measure without trial, to Gorky (Nizhny Novgorod), a city closed to foreigners. Through seven years of exile he lived under the landing guard, the wiretaps and the theft of his manuscripts, and went on hunger strike three times, enduring force-feeding, to win treatment abroad for his wife Bonner. His release meanwhile became a touchstone of Soviet-American relations in the West.

One day in December 1986, the watchers installed a telephone in his apartment. The voice on the line the next day was Gorbachev's, telling him to return to Moscow and resume his patriotic work. That single call was the most dramatic signal at home and abroad that glasnost was not propaganda.

Sakharov accepted the return not as a pardon but as a vindication of conviction, and spent his remaining three years demanding the release of all political prisoners and the radicalisation of reform. To work with the power that had once confined him while never ceasing to criticise it: that was the position the late Sakharov chose.

At the end of December 1986, with the Gorky exile over, Sakharov returned to public life at once. On 14 February 1987 he made his first public speech after release, at the international forum "For a Nuclear-Free World, for the Survival of Humankind". His point was a proposal to handle cuts in intercontinental and intermediate- and shorter-range missiles without being bound to the "package" principle. The proposal soon won Gorbachev's support and led that December to the treaty eliminating intermediate- and shorter-range missiles. In March of the same year, at Lord Nicholas Bethell's initiative, he agreed to the European Parliament's naming its Prize for Freedom of Thought after him; the prize had been established soon after his release from exile, and its first laureates in 1988 were Nelson Mandela and Anatoly Marchenko.

On 3 June 1988 he held his first fully open Moscow press conference, attended by both foreign and Soviet media. Over more than three hours he addressed arms-reduction talks, prisoners of conscience, the right to choose one's own country of residence, the ban on the Crimean Tatars' return, and the Nagorno-Karabakh problem, and held that a return to Stalinism was not possible.

He took part in founding the first independent civic associations of the perestroika era. On 25 June 1988 he spoke at the first authorities-permitted Memorial rally, the first rally speech of his life. He was then elected chairman of the Memorial Civic Committee, and in July and August joined the initiative group of the "Moscow Tribunal" discussion club. In 1988 he also published "The Inevitability of Perestroika" and "You Can Only Fight a Thought with a Thought".

On 6 November 1988, after the Politburo lifted the ban on his foreign travel, he went abroad for the first time in his life, visiting the United States and France, and met President Ronald Reagan, President-elect George Bush Sr. and President François Mitterrand. He returned to the Soviet Union on 13 December. Sources disagree on when the travel ban was lifted, so only the confirmed 6 November departure is stated here.