The World: The Moscow Globetrotters

THE Soviet Union's most ambitious diplomatic offensive in more than a decade is under way. All three members of the Kremlin's ruling troika have announced elaborate travel plans; by the end of the year, they will have visited no fewer than eight countries. When they are not out barnstorming, they will be at home to welcome a number of foreign dignitaries to Moscow. The major comings and goings:

BRANDT IN THE CRIMEA: Following the signing of the Big Four agreement on Berlin last month, the Soviets unexpectedly invited West German Chancellor Willy Brandt to fly to the Crimea for talks with Soviet Party Chief Leonid Brezhnev. Brandt, anxious to get his stalled Ostpolitik back on schedule, quickly accepted. During three days of meetings last week at the secluded village of Oreanda near Yalta, Brandt told the Soviet leader of his concern over the second phase of the Berlin negotiations, involving talks between the two Germanys over access provisions of the agreement. The talks were bogging down over West Berliners' travel rights. Brandt is believed to have pointed out that the East Germans will have to be more flexible if the second phase is to be completed before Christmas. Until the Berlin problem is wrapped up, Brandt does not intend to submit his nonaggression treaties with Moscow and Warsaw to the Bundestag for ratification. The Russians are eager to get both treaties formally approved as a prelude to the convening of a European security conference.

One meeting took place in a room in an artificial limestone cave carpeted with grass and cactus plants. There, following a dip in the Black Sea, Brezhnev and Brandt discussed proposed trade and cultural agreements. India's Prime Minister Indira Gandhi will probably meet Russia's top officials in a more mundane Kremlin setting when she arrives in Moscow this week for a two-day visit.

BREZHNEV IN BELGRADE: With Brandt back home, Brezhnev is scheduled to call on Yugoslavia's President Josip Tito in Belgrade this week. The talks will provide an important clue to Soviet intentions toward the independent-minded Yugoslavs. Will Brezhnev, in the interests of European detente, accept Yugoslavia's unorthodox experiments in political and economic decentralization? How will he deal with Yugoslavia's flirtation with China?

The climate for this week's meeting has been improved by Chinese Premier Chou En-lai's apparent decision not to visit Albania, Rumania and Yugoslavia this fall. For several months, Moscow had grumbled about the formation of a sort of pro-Peking Tirana-Bucharest-Belgrade axis. Moscow was even dropping ominous hints of military intervention against Rumania and Yugoslavia, but the Russians now seem to have cooled off. After Belgrade, Brezhnev's next whistlestop is Paris in late October.

PODGORNY TO HANOI: Soviet President Nikolai Podgorny will visit Hanoi early next month. He will undoubtedly try to exploit North Viet Nam's uneasiness about Richard Nixon's planned visit to Peking. He may also offer Soviet aid in the wake of severe floods that have devastated the Red River Delta. Podgorny is also scheduled to visit Iran for next month's celebrations of the 2,500th anniversary of the founding of the Persian Empire.