MOSCOW, FEB. 9 -- Two leading Kremlin officials opened legislative hearings on the Intermediate-range Nuclear Forces (INF) treaty today with reassurances that the pact will not weaken Soviet security and that the United States can be trusted to adhere to its terms.

Appearing before the joint session of the Supreme Soviet's commission reviewing the INF treaty for ratification, Soviet Foreign Minister Eduard Shevardnadze listed six areas of potential conflict, including what he cited as public concern here that the treaty weakens Soviet defense capabilities by requiring Moscow to eliminate twice as many missiles as Washington.

But Shevardnadze and Defense Minister Dmitri Yazov praised the treaty effusively and called for its ratification. "The treaty is a carefully weighed political and military-technical balance, a balance of interests, a balance of security," Shevardnadze told the Kremlin gathering of legislators, foreign journalists and diplomats.

The Supreme Soviet usually rubber-stamps decisions made by the Kremlin leadership and rarely holds public discussions. In keeping with Soviet leader Mikhail Gorbachev's campaign for political openness, the Supreme Soviet opened the hearing room today to press and diplomats from the United States and Western European countries. The session was broadcast live on state television.

Meanwhile, in a Kremlin meeting with the West German politician Lothar Spaeth, Gorbachev warned NATO against taking any rearmament steps to fill the void left by the elimination of medium- and shorter-range missiles under the INF treaty. "The attempts to undermine the INF treaty with the help of 'compensation' can lead to a very grave political mistake," Gorbachev was quoted as saying by the official news agency Tass.

Yegor Ligachev, the Politburo member chairing the hearing, is reputedly the most hard-line official in the Soviet leadership -- but he struck a compromising tone toward the Reagan administration today. "Neither could there have been any treaty without steps taken in the same direction by the U.S. administration," Ligachev said.

In contrast to the similar INF hearings taking place in the U.S. Senate, where critics of the treaty have warned about the security risks of such arms deals with Moscow, the 90-minute Soviet hearing was marked by complete accord with the government's views.

Ligachev, the second-ranking official in the ruling Politburo, set the tone for the meeting with advice to legislatorss about the ratification process.

"The starting point when studying the treaty," he said, "should be, of course, the attitude of the Soviet people, which has always been characterized by love of peace and striving for good relations with all countries and peoples."

Apparently there were no dissenters. Prompt ratification was urged by each of the six witnesses who appeared.

As the top Soviet military official, Yazov might have been the most skeptical about the treaty. But Yazov, handpicked by Gorbachev last spring, staunchly defended the treaty. "Each word and each figure in it were most thoroughly studied and checked," the defense minister said.

In one suspenseful moment, a Supreme Soviet deputy rose to grill Yazov about the possible reductions in Soviet military personnel that would result from the treaty.

The defense minister replied by saying that the Soviet military would simply redeploy those troops which had been attached to the INF systems. Ligachev promptly put an end to the matter, saying "In other words, the Army is the Army and there is no question of trade unions."

Ligachev, regarded by some western Kremlinologists as a counterweight to Gorbachev's more liberal positions and a potential challenger to the Kremlin leader's position, seemed intent on refuting his image as a hard-liner in a rare appearance before westerners today.

Joking and smiling, the smartly dressed Ligachev added praise for Gorbachev, saying the leader's newly announced stance on Afghanistan was "brilliant."

Ligachev and other officials referred to doubts about the treaty posed by Soviet letter writers to official periodicals.

"They want to get more information on what the treaty offers us and . . . how it bears on the Soviet Union's defense capabilities," Ligachev said.

"Soviet people also want to know whether the treaty will be approved by the U.S. Senate and whether there are guarantees that the U.S. will honestly abide by it."

DELTA 181: HOW THE EXPERIMENT WORKED

1. Two-stage Delta rocket launched satellite into orbit 195 nautical miles above the Earth.

2. In two phases, the satellite released 15 mock warheads and decoy warheads into space.

3. The satellite tracked the 15 objects as they moved away, maneuvering above and below them for different views.

4. Using a variety of infrared and optical devices, the satellite attempted to measure the appearance or "signature" of the mock warheads and decoys in space.