What was going on when I was born?

Braniff International left the door open yesterday for further negotiations to revive part of the airline while meeting a court deadline to submit a plan of reorganization. The plan, which was filed in a bankruptcy court in Fort Worth, calls for liquidation of most of Braniff's assets, leaving only a small company that would provide ground services employing about 200 people and with sales of about $12 million a year. However, the plan also states that the board of directors will continue until May 16 ''to develop and propose a flying operation'' using up to 31 of its Boeing 727-200 aircraft to be leased at market prices. Braniff can amend its reorganization plan as long as the changes are made within 60 days, and still allow time for the 50,000 Braniff creditors to vote on it.

President Reagan denounced ''the vicious terrorist bombing'' of the United States Embassy in Beirut today as ''a cowardly act.'' He vowed that the United States would not be deterred from its efforts to bring peace to the Middle East and the withdrawal of foreign troops from Lebanon. In a brief statement in the White House Rose Garden about six hours after the attack, Mr. Reagan said he would ''rededicate the efforts of the United States'' to those goals. Washington was unable to provide exact casualty figures immediately because some bodies were unrecognizable, officials said, and more dead and wounded were expected to be found in the rubble.

While they were students at the Harvard Business School two years ago, three young men undertook a study for the National Aeronautics and Space Administration addressing the question of how the Government might encourage more private investment in space operations. One problem, they discovered, was the lack of entrepreneurs willing to take risks to ''make things happen.'' So, upon graduation, David W. Thompson, 29 years old; Bruce W. Ferguson, 28, and Scott L. Webster, 30, decided to act on their own recommendations by setting up their own company, the Orbital Systems Corporation. They borrowed money from banks and other financial institutions and raised capital from private investors, including the Space Foundation of Houston. And finally, they negotiated a deal with NASA, which was announced yesterday in Washington, to develop and market a privately financed propulsion system for launching satellites from the space shuttle.

A Government study, ordered by President Reagan, of the foreign debt crisis has apparently concluded that the problem will be solved by economic recovery among the major industrial nations. This finding is likely to play a critical role in determining the American negotiating position at the seven-nation economic summit conference to be held at Williamsburg, Va., in late May. It would argue, for example, against any major new initiatives to deal with the debt problem. However, according to officials who have read the 28-page, doublespaced third draft of the classified report, there are strong dissents to this optimistic view from both the Central Intelligence Agency and the staff of the National Security Council. Both agencies are said to be quite concerned about the ability of developing countries to keep up with their debt repayment. According to one account, these agencies argue that the problem could become unmanageable in the next 12 to 18 months, even with fairly strong economic recovery.

Pulitzer Prizes were awarded yesterday to '' 'Night, Mother,'' a play by Marsha Norman, and to ''The Color Purple,'' a novel by Alice Walker. The play, about a mother and her daughter, who announces that she is about to commit suicide, was reviewed by the Pulitzer's nominating jurors at the American Repertory Theater in Cambridge, Mass., before it moved to Broadway. The novel, published by Harcourt Brace Jovanovich, is written in the form of the letters of two black sisters, one living in the rural South and the other a missionary in Africa. In journalism, The New York Times and The Washington Post each won two awards. The prize for international reporting was shared by Thomas L. Friedman of The Times and Loren Jenkins of The Post for their coverage of the war in Lebanon.

Because of an editing editor, an article on Saturday incorrectly described a Wall Street Journal report on a reputed remark by President Reagan to King Hussein of Jordan. The Journal article did not specify how or where the remark was made.

Officials at dozens of utilities in Washington State today hastily arranged meetings to decide whether to meet scheduled payments to the Washington Public Power Supply System. The gatherings were organized after Federal Judge Joseph H. Coleman earlier today ordered 65 utilities collectively to pay nearly $30 million in past-due bills into escrow accounts for the troubled supply system. ''We assume that a majority of the utilities will pay in,'' said John Britton, a spokesman for the supply system. ''But we don't know whether Judge Coleman will allow us to draw the money out to pay our bills.''

HANDED people, already burdened by minor inconveniences in a right-handed world and by a language full of such ego-deflating figures of speech as two left feet, out in left field and left-handed compliment, also seem to face an increased risk of certain disorders that can further impair the quality of their lives. A series of new studies show that left-handed people are more likely to suffer from learning disabilities, stuttering, migraine headaches and, according to the latest findings, autoimmune diseases, like ulcerative colitis, myasthenia gravis and celiac disease, in which the body attacks its own tissues. The researchers emphasize, however, that their findings do not mean that left-handed people are at a biological disadvantage. Rather, they consider left-handedness an example of ''biological diversity'' that may be disadvantageous in some ways and beneficial in others. ''Until you look at the full range of conditions and overall life expectancy among left-handed people, you cannot say whether it's a disadvantage,'' said Dr. Norman Geschwind, a leading researcher in the field. ''It could be that left-handed people have only half the rate of lung cancer that right-handed people do.''

The Dow Jones industrial average, in another of the dramatic surges characteristic of the stock market rally that began last August, rose to its fourth consecutive record high yesterday. As they have since last August, analysts attributed the market rise to lower interest rates and all the benefits of recovery from recession, particularly higher corporate profits. But it was the expectation of recovery that had been pushing up stock prices until recently, analysts said. The market is rising now, said William LeFevre, an analyst with Purcell, Graham & Company, because ''the recovery is being accepted much more widely as real.''

A bomb exploded in the American Embassy in Beirut today, killing at least 33 people and wounding more than 80 others. Both the Lebanese police and American officials said there was evidence suggesting that the explosion may have been caused by a car packed with TNT driven up to the embassy's front door and detonated in an suicide attack. A secretive pro-Iranian Moslem group called the Islamic Jihad Organization said it was responsible for the bombing, in a telephone statement to the Beirut office of Agence France-Presse. The same group said it was responsible for the grenade attack against a group of American marines on March 16 in which five men were wounded.

''This criminal attack on a diplomatic establishment will not deter us from our goals of peace in the region.

A dispatch by The Associated Press in Sports Pages last Thursday incorrectly described the extent of reading deficiencies found among football and basketball players at Iowa State University. The tests on which the report was based were limited to 28 incoming Iowa State players.