Two weeks ago Sue Lathbury, 35, of Selbyville, Del., was camping with her husband here on the Eastern Shore when two lifeboats filled with Russians landed on the beach of nearby Assateague Island.

The Russians had the Soviet flag mounted on the back of their lifeboat "and that bothered me for some reason," Lathbury said. "I guess my first thought was 'It's the enemy' . . . I mean, that's the way we've been conditioned."

The Russians, however - 60 or 70 of them from a Soviet research ship anchored offshore to conduct international weather rocket tests - immediately disarmed them with curiously and broken English.

"They asked a lot of questions about what kind of work we did and how much money we made," said Lathbury, a print shop supervisor in Selbyville. "They seemed amazed that we had two days off every week. They said they worked seven days. They asked what we did on our days off. My husband made a drinking motion with his arm and they all laughed and clapped at that.

"They were some drinkers . . . one guy picked up a full fifth of Canadian Mist and drained it right down you know, chug-a-lug. Then he rubbed his stomach sort of casual and said, 'Water good'."

Lathbury, who said she and her husband had never been to a foreign country and "never thought we'd see that many foreigners," found themselves fascinated by the Russians and made a point toreturn to Assateague the following Sunday. "There were other people there that time and the Russians seemed much more at ease," she said. "one local guy from Chincoteague brought a picnic he was sharing with the Russians. They were tearing up a chicken and having a good time. They gave us Russian bread, which was wonderful," she said.

Capt. Oleg Rostovtsev, commanding officer of the 409-feet research ship, Akademik Korolev, said that, for his part, the visit "has been a very interesting experience. We learned to enjoy your game of Frisbee and Americans we meet on the beach learned our ancient Russian game of chekharda. (The captain described chekharda as a game in which one team of players locks arms and another team jumps on their backs until the team on the bottom collapses.) "Please," said the captian, "why aren't you drinking more of our pepper vodka?"

The Akademik Korolev arrived off Wallops Island Aug. 5 after a three-month voyage from her home port of Vladivostok by way of Hawaii and panama. For most of the stay, her 134-member research staff and crew were occupied conducting 22 joint rocket firings with a National Aeronautics and Space Administration team on Wallops Island near here.

The firings were designed to compare meteorological measurements made under identical condition by NASA and Soviet rockets so as to better calibrate and interpret data exchanged from individual tests in various parts of the world.

Morris Tepper, program manager, said the tests were highly successful, yielding full results on 17 of the 22 shots and nearly full results on four more. He and other Russian and American scientists said the data from the tests, which must now be evaluated, may help explain a puzzling discrepancy in U.S. and Soviet measurement, first noted in 1972, which appears to show the stratosphere and mesosphere 18 centigrade degrees colder in the eastern hemisphere than in the west. At least part of this difference they believe may be due to variations in the measuring systems themselves.

But when they weren't firing rockets from their ship, the Soviets were exploring the Eastern Shore. The Russians became so interested in the Americans they met that they started asking everyone out to the ship for a tour. Coast Guard officials, paling at the prospect of vodka-soaked visitors transferring to and from small boats on a rolling sea, exercised a quiet veto on that, which the Russians seemed to understand.

"Is not just bureaucrats," explained Boris Lipovsky, a radio electronics supervisor on the Akademik Korolev. "Is for safety."

The Russians' enthusiasm for American games was such, Lathbury said, that "one of them played horseshoes for 2 1/2 hours straight." Frisbees, to which the Soviets were introduced at a NASA-sponsored "mini olympics" at Wallops seemed to hold unending fascination for the flight-minded scientists. On a tour of nearby Accomack County many of the Russians carried the purchased Frisbees with them, filling them with potato chips, at receptions along the way.

NASA and Eastern Shore officials were hosts for three days of tours for the Russians last week, showing them such local attractions as the Holy Farms poultry processing plant in Temperanceville, the old debtor's prison in Accomac and the Campbell Soup factory in Pocomoke City, Md. The Russians ingested great quantities of the local cuisine, including soft shell crab sandwiches, oyster fritters and freeze-dried, deep-fried strips of deep sea clams.

They liked it all.

"Many of us have been to cities in the United States before," said Evgenity Nelepov, assistant to the captain for scientific affairs.

"But the major cities of the world have over the recent years become more and more alike, losing the individual characteristics and cultural tradition that each nation calls its own. To find these national characteristics one must go to the small villages and rural areas where traditions and local culture endures," Nelepov continued. "That is why this visit here has meant so much to us."

Tuesday they tried to say thank you with a press tour and reception on the Akademik Korolev which left some 30 reporters, photographers and assorted media hangers-on awash in borscht, pepper vodka, salmon canapes and Hungarian wine. There were toasts to friendship, toasts to the captain, toasts to the reporters, toasts to the crew, toasts to the women present, and a great many competitive macho toasts with peper vodka at which the Russians seemed to excel.

Yesterday the Akademik Korolev weighed anchor for Baltimore where the Russians planned to do it all over again, this time without rockets.