MOSCOW, OCT. 5 -- The Soviets have earned high marks for a major international gathering on space science here, not only from scientists but also from a White House official, who expressed optimism about superpower cooperation in space.

As the Soviets celebrated the 30th anniversary of the first sputnik, or satellite, they have used the three-day forum to push for increased cooperation by the superpowers on peaceful space missions. They flew in 130 American scientists and hundreds from elsewhere.

Comments by Thomas P. Rona, deputy science adviser to President Reagan, indicate that the administration may be softening its resistance to the notion.

"The Soviets handled this very well. They clearly did not use this for heavy-handed propaganda," Rona said in an interview. "I was surprised to see the even-handed treatment they gave to our own space program, instead of arguing who leads who."

Rona noted that the Soviets avoided mentioning the sensitive topic of the president's space-based Strategic Defense Initiative.

In the administration's approach, he said, "the key phrase is 'relations evolving slowly.' " But he added, "We are anxious to cooperate" under certain conditions. "There's a chance that space programs contribute to decreasing the level of distrust."

Rona issued an invitation to the Soviets to attend a conference in the United States next year on the impact of space sciences on the human community.

Rona has held posts at the Massachusetts Institute of Technology and at Boeing and was a Defense Department official before moving to the White House. He acknowledged that there are strong opponents of cooperation within the administration who have made it difficult for American scientists to participate in Soviet space endeavors. However, he said, "we all evolve."

American scientists have pressed for greater cooperation with the Soviets. A major topic of this conference was the perception that the global "center of gravity" for international space science is shifting from the United States to the Soviet Union.

One reason for this is that the U.S. space fleet is essentially grounded, while the Soviets have an abundance of launch vehicles, enhancing Moscow's appeal for scientists from Europe and elsewhere.

"I used to travel to the States frequently and now I find I come here," said X-ray astronomer Ken Pounds of the University of Leicester in England. The next opportunity to fly an experiment in his field on a U.S. craft is nearly a decade away, he said. He said of the Soviet project in which he is taking part, "When you're hungry and somebody offers you food, you say thank you."

But launch capacity is not the only consideration, several top scientists said.

"The U.S. policy toward cooperation is very, very poor," said Jacques Blamont, chief scientist of the French space agency, who in the past has been critical of aspects of both the U.S. and Soviet programs. He was a member of the forum organizing committee. "The Soviets look generous by comparison. NASA is not very open to our ideas, but the Soviets say, 'Give us your ideas,' and sometimes they take them and improve on them."

Thomas Donahue, head of the space sciences board of the U.S. Academy of Sciences, said, "The stumbling state of the U.S. program, in contrast to this one over here, is shocking to a veteran like me. Not so long ago, meetings like this would have occurred in the United States. Now . . . this is where the action is."

Donahue and several others said they are aware that their presence benefits their host, Roald Sagdeyev, head of the Soviet Academy of Sciences space research institute, within his own country.

"To some extent we're being used, but in a good cause," Donahue said. "We're being used to strengthen Sagdeyev's hand and the Soviet civil space program. The civil and military programs compete for support here," too.

Many of the scientists argue there is no sensible alternative to international cooperation, given the growing size and complexity of space missions and because of its implications for peace.

"Some people speak of cooperation in space as an ideal. But you're no longer talking about ideals. You're talking about the requirements of a new era," said Harvey Meyerson, an aide to Sen. Spark M. Matsunaga (D-Hawaii).

Matsunaga and others are organizing an International Space Year for 1992 -- a congressional initiative -- to coordinate international space efforts and mount a massive education campaign on the uses of space for studying and protecting the Earth, as well as for conducting scientific research.

"Nationalism doesn't apply when you're talking, for example, about solving problems of drought, or deforestation," Meyerson said. "And the massive space missions envisioned for around the turn of the century will have to be coordinated."

However, American scientists had to fight hard, they said, to get a modest experiment aboard the Soviet Vega mission to Halley's Comet, in which 14 nations participated.

Many scientists discounted security arguments against cooperation, saying vital technology could be protected.