How the Soviet Union gathers US technology

The Soviet Union uses a number of methods to obtain US technology, according to testimony given at Senate hearings earlier this year. Among them:

* So-called ''hand in the safe'' information-gathering by Soviet spy organizations, chiefly the KGB (Soviet Committee for State Security) and the GRU (Chief Intelligence Directorate of the Soviet General Staff), and their Warsaw Pact allies. Tactics include blackmail, bribery, and extortion, used to obtain high-priority technology that cannot be obtained through less-risky techniques.

* Information published by the US government and made available to the public by federal agencies. The Freedom of Information Act is used to gain access to formerly or currently classified documents.

* Scientific exchanges, in which the US agrees to furnish technical information, and student exchanges through ''the best technology transfer organization in the world,'' the US university system.

* Dummy companies that buy high technology for illegal export to the Soviet Union. In one known case, the Soviets were able to equip a modern semiconductor plant through illegal purchases made through companies in southern California and Western Europe.