Ike’s Granddaughter, Soviet Scientist Marry : Romance: In a storybook ending, a close adviser to Gorbachev takes the hand of former U.S. President’s kin.

Not long ago it would have been too preposterous an idea for any but the most far-fetched of romantic novels: The granddaughter of a former American President marrying a top Soviet space scientist and friend of the country’s Communist Party chief.

But the world has been turned on its head since then, and Friday, an idea too outlandish for fiction became fact. Susan Eisenhower, 38, granddaughter of the late Dwight D. Eisenhower, married Roald Z. Sagdeyev, 57, adviser to Soviet President Mikhail S. Gorbachev and close friend of the late Nobel Peace laureate and physicist, Andrei D. Sakharov.

Their union, everyone agreed, was both a measure of the political change in the world and a symbol of hope for its future.

One of the Russian guests even showed up wearing an “I Like Ike” button, which mysteriously found its way here after one of Dwight Eisenhower’s 1950s election campaigns.

There were two ceremonies, a standard, five-minute civil procedure at a special Soviet “marriage palace” used for important weddings, followed by a short religious service at the elegant official residence of U.S. Ambassador Jack F. Matlock Jr.. The groom, according to one guest at the second ceremony, said his vows in Russian, the bride in English.

The marriage happened to coincide with an important official visit to Moscow by Secretary of State James A. Baker III. And it came just two days after a historic decision by the Soviet Communist Party leadership to move toward a multi-party system and an American-style presidency--”convergence” by almost any standard.

Baker, who would normally have been Matlock’s guest at the official Spaso House residence during his stay, deferred to the wedding and sought quarters elsewhere. He reportedly did not even make it to the reception because his talks with Foreign Minister Eduard A. Shevardnadze and Gorbachev went longer than expected. But Baker’s wife, Susan, was there.

“There have been many joint Soviet-American projects, ranging from space to biotechnology, but today’s ‘project’ is sui generis (unique),” wrote a correspondent for the official Tass news agency in his account of the union. Many other Soviet-American marriages have occurred, he added, but never involving people of such “high status.”

Most of the approximately 300 guests at the Spaso House reception were Soviet citizens. The media was barred except for a handful of photographers permitted inside for a five-minute “photo opportunity.”

A few clusters of ordinary Russians stood in a park across the street watching as a parade of official black Volga and Chaika automobiles sped up to the front gate and disgorged their well-dressed passengers. It was obvious by the large number and variety of fur coats on display that the animal rights movement has had little echo here in what American residents sometimes call “The Big Red Apple.”

“Good day, comrades!” said the jovial police guard at the mansion’s entrance as he intercepted arriving guests. “Your invitations, please.”

A few of the guests were famous enough that he dispensed with the formality. “Of course you have an invitation,” he remarked to one senior government official. Then, with a salute, a smile, and a wave toward the entrance, he invited: “Please!”

Many of the Soviet guests brought gifts, some of them bound in cheap but scarce white wrapping paper, others carried in plastic bags.

Foreign Ministry spokesman Gennady I. Gerasimov, whose face and voice are familiar to television viewers around the world, struggled up the icy driveway with his wife gripping his left arm and carrying a large basket of flowers in his right.

Among other guests were Sakharov’s widow, Yelena Bonner, the Russian poet Yevgeny Yevtushenko, and Occidental Petroleum Corp. Chairman Armand Hammer.

The bride wore an off-white, two-piece suit. Her daughter by a former marriage was a flower girl. Sagdeyev also has two grown children from an earlier marriage, which ended in divorce.

The couple met in Chautauqua, N.Y., three years ago at a conference on Soviet-American relations. According to the Tass account of the meeting: “At a reception, the Soviet academician, giving the lie to the widely held view of the Russians as square and reserved, mounted the stage and, applauded by his audience, sang ‘When the Saints Go Marching In,’ and then danced, and danced, and danced with Susan.”

Eisenhower, one of four children of John Eisenhower, later helped transcribe and edit the English-language version of Sagdeyev’s memoirs, which are soon to be published in the United States.

Eisenhower has called the marriage an indication of how times are changing for the better. She has said the couple was anxious about the reaction when they notified Soviet and American authorities of their intention to wed, but that fortunately their relationship evolved at a time that this country was changing dramatically.

It all adds up, said the normally unromantic Tass, to a “sensational” love story.