IF ONE had to explain to a newly arrived Martian why the new strategic arms limitation agreements will face serious opposition - and possible rejection - in the Senate next year, there would be no better place to begin than with the 12 senators who visited the U.S.S.R. for eight days last month.

Their trip was not conclusive for any of them, judging by interviews with 10 of the 12, but it was a discomfiting tale of two cultures that suggests many of the problems the Carter administraction will face when it tries to sell SALT next year.

Sen. Abraham Ribicoff (D-Conn.), who led the senatorial delegation, may have summarized the heart of the atter when he got back to this country: "Having returned from the Soviet Union," Ribicoff said, "I am convinced that the two superpowers basically do not understand each other."

Ribicoff came home with his pro-SALT instincts intact, but others in the group were shaken by what they saw and heard. Many brought back new misgivings about Soviet attitudes and about the feasibility of fundamentally improving Soviet-American relations.

Sen. Henry Bellmon (R-Okla.), the ranking Republican on the trip and a man known to his colleagues as serious and hard-working, made a representative comment:

Sen. John Durkin (D-N.H.), for whom this was a first visit to Russia, said he thought it would take Americans another generation to really understand the Soviet Union - and that the Soviets would need two generations to understand the United States.

In part such feelings grew out of the senator's encounters with Premier Kosygin and another member of the ruling Politburo, Grigory Romanov, both of whom demonstrated imperfect knowledge of the workings of the Senate, but insisted they understood exactly how it works.

The encounter with Kosygin was particularly annoying to the senators. It began with a statement from Ribicoff in which he noted the role the Senate will have to play in approving new Salt agreements, and then expressed concern about the points of Soviet-American disagreement around the world that worry some senators.

One of those was the report of new Soviet Mig-23 fighters in Cuba, and when Ribicoff mentioned them he apparently angered Kosygin. Whatever the cause of his anger, the Soviet premier reacted harshly.

"Thank you for explaining to me what the U.S. Senate is," Kosygin began sarcastically. "You know that we know what the United States Senate is. An we cannot agree with your explanation of how things will stand at the time of SALT" in the Senate.

As Ribicoff put it later, Kosygin then proceded to demonstrate how little he did know about the workings of the Senate. He told the senators that "your voters sent you to the Senate to fight for peace," and therefore they would have to support a SALT agreement or face defeat at the polls.

"Listening to you," Kosygin said, "it sounds like only the Soviet Union is really interested in SALT." He said that proponents of SALT were "the forces of peace," but those who opposed iw would be aligned with the "the forces of war." When Ribicoff tried to respond, Kosygin said. "Why don't you just stop talking and let someone else speak?"

The meeting went so badly that the Soviet "parliamentarians" who were the senators' official hosts apparently asked if Brezhev would receive the Americans to try to repair the damage. The Soviet president agreed to do so on short notice, and that session was more friendly.

Romanov, the Communist Party boss in Leningrad, told the senators at another occasion that President Carter could compel members of the Senate to vote for SALT by threatening to withhold money from their future campaigns. Selling Vacuum Cleaners

MANY OF the senators were upset by the repetitive assertions of the Soviets they met, all of whom seemed to insist that the U.S.S.R. was the homeland of peaceful intentions, wise policies and statemanship, and all the world's problems are the fault of Americans and their friends (or the Chinese).

Observed Sen. Durkin: "I told one of them privately, I used to sell vacuum cleaners as a kid, and I'm beginning to get the feeling that you're selling us a vacuum cleaner."

Attempts by several senators to discuss substantive aspects of the SALT negotiations were invariably frustrated (with the exception of one memeting held by Sen. Sam Nunn, described in the accompanying article). Kosygin said he did not expect senators to be bogged down in the technical details, but rather anticipated that they would discuss "the basic issues of peace."

At a large meeting in which the senators discussed bilateral issues with their hosts from the Supreme Soviet, Sen. John Glenn (D-Ohio) tried to explain some of the reasons why Americans are concerned about Soviet intentions.

Glen recited al long list of concerns, from the number of Soviet tanks in central Europe to the large percentage of gross national product the Soviets devote to defense spending. He also noted that many of his Ohio constituents had roots in the Baltic states and Eastern Europe, and that they wear deeply suspicios of Soviet power generally. Many Americans felt the Soviets had occupied those areas, and might someday use them as a staging area from which to attach the West, Glen added.

As Glen spoke there was much tittering and giggling on the Soviet side of the table. Glen noted this and said he hoped the Soviet side realized he wasn't joking, that these were serious matters.

Leonid Zamyatin, director of the Communist Party's propaganda department, replied harshly that the Soviets were not smiling because they failed to taken glen seriously, but because they had not heard such a speech since "the days of the Cold War." One Evening of Warmth

The SENATORS found they had virtually no opportunity for serious give-and-take with their Soviet hosts, all of whom preferred making speeches to holding discussions. The one chance the senators got for more relaxed conversation came on the evening when all of them were invited to the homes of Soviet officials for dinner.

This was an unprecedented gesture for the Soviet side, which in the past has rarely allowed senior officials to invite visition Americans into their apartments of country dachas. Several commented on the relatively low standard of living of their hosts. "The apartment could have belonged oo 2 lower-middle-class American," one senator said. Many of the senators said these parties were a high point of the trip.

Sen. Bellmon proposed a toast at the dinner he attended "to the past, when we were allies, and to the future, when we can be friends in the daytime as well as at night." The atmospher that evening was much warmer than in the daytime meetings, Bellmon said.

On some aspects of their experience, different senators came away from Russia with radically fifferent impressions. Some, for instance, thought Romanov, the Leningrad party boss, was a rather nasty hawk; others thought he was an interesting and direct fellow.

Several senators said they though Brezhnev seemed more interested in peace with America than many of his colleagues. Sen. Richard S. Schweiker (R-Pa.), for example, said he felt the Soviet leader was "the peacemaker of the group."

Schweiker was also one of many senators on the trip who was impressed by the vivid memory of World War II in Russia and the attitude of ordinary Russians toward the possibility of future wars. He said he was not prepared for "the sincere desire of the people for peace" that he found.

The Soviets filled the senators' schedules with visits to war memorials and wreath-layings. Some of them thought this was overdone, but most in the group said it was clear to them that the war-in which 20 million Soviets died-had left deep scars on the country.

SENATORS, From Page D1

"They were abrasive, arrogant. I was kind of turned off by the whole experience. . . . I'm one of those who's felt the arms race is deplorable, so I tend to be for an agreement. But at the moment I'm inclined to feel we should turn down the SALT agreement and tell the Soviets they have to clean up their act across the boatd."

Bellmon is the sort of senator whom administration lobbyists fell they must win over if SALT is to be approved by two-thirds of the Senate. Despeite his conservative state and background, Bellmon did vote for the controversial Panama Canal treaties, and the administration has been counting him as a potential SALT supporter.

He may still be one, but the anger and frustration Bellmon brought home from Moscow typify a common emotion inside the Senatre that could do SALT in next year. As they demonstrated again to this traveling band of senators in Moscow, the Soviets are not good at dealing with this emotional reaction, but in fact tend to aggravate it.

It should be emphasized that this frustration was not universal. Several senators in the delegation who had previous experience dealing with the Soviets found their behavior both typical and predictable, and were not unduly put off by the steady drumbeat of Soviet propaganda they heard and the general refusal to enter into serious give-and-take. One, who asked not to be quoted by name, said his colleagues simply didn't realize what they would be in for in Moscow, and reacted rather emotionally.

Still, in a Senate where at least 25 "no" votes on SALT seem guaranteed in advance-and where 34 "no" votes would block the agreements-senatorial emotions could prove a crucial factor. The "Linkage" Dilemma

BELLMON'S CONCERN about "the Soviets' act across the board" was typical of these senators. According to Ribicoff, this idea of "linkage" - connecting approval of SALT to more restrained Soviet behavior in other arenas-emerged as the key issue on the trip.

"I emphasized (to the Soviets) that there has to be linkage," said Sen. Sam Nunn (D-Ga.), a member of the Armed Services Committee who, according to other senators on the trip, had the best technical knowledge of all of them about SALT.

SALT will have trouble in the Senate "if the Soviets don't take a more positive approach to linkage" with issues like the Soviet-Cuban presence in Africa and human rights, according to Sen. Dennis DeConcini (D-Ariz.). "There has to be some demonstrative step by the Soviets to build some credibility and trust," DeConcini added, "but it's just not there."

Other senators spoke in the same vein, suggesting that their SALT vote would depend in part on a general assessment of Soviet behavior.

But the many Soviet officials they met during their eight-day visit consistently refused to talk about SALT in terms of any other issues. They insisted either that it be considered entirely independently, or that it be regarded as the key to improve elations in other areas.

Ribicoff though he had an answer to the linkage dilemma, which he described as a tension between "linkage before (SALT) or linkage afterward."

He proposed that President Carter and the Soviet leader, Leonid I. Brezhnev, use the time between the initialing of a new arms pact and action on it by the Senate to deal constructively with other points of Soviet-American tension, hopefully leading to new signals of restraint from Moscow. Ribicoff added that he did not believe that Carter or Secretary of State Cyrus Vance have "thought these things through" yet. The administration has taken the position that SALT cannot be formally linked to other matters, but that Senate reaction to it will inevitably reflect Soviet behavior in unrelated areas. "We Cannot Agree"

THE SOVIETS clearly did not intend to annoy this delegation of senators. On the contrary, they received an unusual red-carpet welcome, and had opportunities to meet an unusual number of high-ranking Soviet officials, including Brezhnev and Premier Alexei Kosygin.But many of the senators felt that they were staring across a deep cultural gulf when they sat opposite these officials at the U.S.S.R.'s ubiquitous felt-covered conference tables.