What was going on when I was born?

The space shuttle astronauts launched a second communications satellite from the Columbia's bay today, completing their primary objective. The satellite, Canada's Anik C-3, sprang free of the shuttle as the astronauts coasted over the Pacific Ocean on their 22d orbit. Spinning for the sake of stability and cloaked in a multitude of dark blue solar cells, the cylindrical satellite drifted miles away before its rocket fired to raise it toward a higher orbit over the Equator. Dr. Joseph P. Allen, who supervised the operation, reported its success in a voice rising with excitement.

The Nuclear Regulatory Commission today ordered an Ohio utility to halt construction of its nearly completed atomic power plant until an independent review has found that the plant meets the Government's safety requirements. The subject of the commission's unusual order is the William H. Zimmer Nuclear Power Plant on the Ohio River near Cincinnati. The $1.6 billion plant has been under construction by the Cincinnati Gas and Electric Company since 1972. James G. Keppler, head of the Regulatory Commission's regional office that oversees the plant, estimated that the independent review could take at least six months.

Argentina's military rulers have asked the country's political leaders to agree to a pact, before a return to civilian rule, on how to deal with major issues facing the country. The issues include responsibility for the war with Britain over the Falkland Islands and the deaths and disappearances that took place during a guerrilla insurgency in the 1970's. The junta, in an announcement Thursday night on national radio and television, did not give its position on the 15 issues that it listed. Politicians Express Fear But many political leaders expressed fear today that unstated conditions lay behind the list and that the military might be backing off from its promise to restore civilian government by March 1984. The country has been under military rule since 1976.

Yuri V. Andropov, who surprised Washington by the speed with which he outmaneuvered rivals for the Soviet Communist Party leadership, is regarded here as a tougher, smarter, shrewder competitor for the United States than Leonid I. Brezhnev. His first speech, emphasizing Soviet military might, was read here as an expected show of forcefulness, an echo of Mr. Brezhnev's final theme, and a political bow to the important constituency of the armed forces at the vulnerable moment of succession. Washington is looking for a more definitive outline of policies in the coming days. On the record, the new Soviet leader is seen by American specialists as a man of contradictions, a cultivated and fairly well traveled party careerist personally fascinated by Western society but concerned that Soviet society has become too corrupt and consumerminded, a strong advocate of the Soviet military buildup but a backer of negotiations with the West who has warned on occasion that detente was in danger and required ''constant movement forward.''

Yuri V. Andropov was chosen by the Communist Party's Central Committee today to succeed Leonid I. Brezhnev as its General Secretary, making him the Soviet Union's principal political leader. Until six months ago, Mr. Andropov headed the K.G.B., the Committee for State Security, and was in charge of the internal security police and foreign espionage operations. His appointment today came barely 48 hours after Mr. Brezhnev's death. The selection was said to have been unanimously approved by the Central Committee. Mr. Andropov was nominated for the post by Konstantin U. Chernenko, a longtime lieutenant to Mr. Brezhnev who had been considered Mr. Andropov's principal rival for the top party job.

The National Commission on Social Security Reform reached agreement today on the need to begin bringing all employees of the Federal Government and of private, nonprofit institutions under the Social Security system. The 15-member, bipartisan commission also agreed to explore ways to ''stabilize'' the Social Security system to make it less vulnerable to economic fluctuations. The implication was that the present costof-living formula, which ties benefits to the Consumer Price Index, must be modified. That is a point that the commission chairman, Alan Greenspan, has been making for months.

In the view of Western diplomats here whose job it is to interpret what is going on in Mozambique, the country's sole political party has shifted somewhat from the staunch pro-Soviet line on which it took power in 1975. The change has been signaled in a series of recent events. There was, for instance, an agreement with Portugal for small arms, the first such deal with a member of the North Atlantic Treaty Organization and the first sign of warmth toward the former colonists. A food aid agreement with West Germany involved signing what is called ''the Berlin clause,'' tacitly acknowledging Bonn's interpretation of the status of Berlin, albeit in return for a West German note defining the divided city in a manner acceptable to Mozambique.

Officials said that about 6,000 Salvadoran troops moved on rebel positions in northern El Salvador today while 2,000 Honduran soldiers lined up across the border to block escape.

Prime Minister Giovanni Spadolini asked Parliament today to confirm his power to rule.

Gen. Kenan Evren assumed the office of President today. In an inauguration speech, General Evren praised Turkey's belief in parliamentary democracy and said preparations had begun to have general elections in the fall of 1983.

Arab countries today reopened their campaign in the Security Council to halt Israeli settlement in the West Bank but, at the urging of the United States, confined themselves to making speeches. The Arab diplomats strongly condemned Israel's policy as a threat to peace. They held back, however, from offering the customary Council resolution that ends debates.

The death toll in an explosion that destroyed an Israeli military headquarters building on Thursday at Tyre in southern Lebanon reached 47 today as rescue workers continued to hunt through the rubble for survivors. Three Israelis were rescued alive during the day, and military officials said 50 to 60 people were still unaccounted for, including 27 Israeli security agents. Of the 47 dead, 32 were Israelis, most of them soldiers, and the remaining 15 were Arabs, most of whom had been detained in the building's upper floors for questioning. More than 25 people injured in the explosion have been hospitalized.