Soviet Ambassador Anatoliy Dobrynin today renewed Moscow's attacks on President Reagan's proposed Strategic Defense Initiative (SDI), calling it an attempt to militarize the heavens.

Dobrynin also said that the success of the arms control negotiations in Geneva depends on the ability of both sides to adhere to the agreement on the talks that Secretary of State George P. Shultz and Soviet Foreign Minister Andrei Gromyko signed last January. Dobrynin noted that the Reagan administration had agreed in advance to work to prevent an arms race in space.

Dobrynin made his remarks in the midst of a lively debate over the U.S. and Soviet roles in the arms race during a unique five-day gathering of more than 50 specialists on Soviet-American relations, including former presidents Jimmy Carter and Gerald R. Ford. Dobrynin heads a four-man Soviet delegation appointed by new Soviet leader Mikhail Gorbachev.

Moscow's longtime envoy in Washington described the current state of U.S.-Soviet relations as "tense, complicated and unstable." In the past five years, he said, "we have seen just how stubborn the legacy of the Cold War really is."

Dobrynin said "intense propaganda" surrounds the discussion of the "Star Wars" Strategic Defense Initiative in the United States, including the argument that it would make it easier to negotiate agreements on strategic weapons. The creation of space-based missile defense will have only one result, he said: the arms race will become more intensive. Dobrynin also reemphasized Moscow's threats that U.S. development of space weapons will lead to a buildup of Soviet offensive weapons.

In a sharp response to Dobrynin's remarks, Secretary of the Navy John F. Lehman Jr. said that the Soviets, with time, will come to view the SDI as "very much in our mutual interests." He added that reorienting weapons from strategic deterrence to defense can only be stabilizing and not destabilizing.

Lehman also rejected the Soviet Union's threat that it will respond to U.S. space-defense research by building more and bigger offensive weapons. "They won't do that," he said, "because it doesn't make common sense."

Ford called for the United States to take a firm stand on "clear-cut" Antiballistic Missile (ABM) treaty violations by the Soviets.

He said: "The Soviets can't expect us to live up to the agreements when they, in the case of the ABM, failed to live up to it and in effect have shown a lack of good faith in the SALT II and START strategic arms agreements."

Referring to Gorbachev's recently announced freeze on deploying Soviet intermediate-range missiles until November, Dobrynin said he regretted that the United States had refused to freeze its missiles, too.

He said Moscow would seriously consider any counterproposal from the Reagan administration.