Great Unknown Awaits Cosmonaut : Space: After 10 months in orbit, Krikalev is coming home. He’ll find no Soviet Union, a renamed hometown and a new country to land in.

High above Earth, the Rip van Winkle of the Space Age said Friday he’s greatly looking forward to coming home next week. And like Rip, he said it could take time for him to wake up to a new world.

Speaking from orbit, former Soviet cosmonaut Sergei K. Krikalev told reporters that he is in “high spirits” and laughed at rumors that he has fits of depression.

But on his 306th day in space, the man from Leningrad now in the Mir space station made no secret of his desire to return home--even if it now has retaken its original name: St. Petersburg.

“I have accumulated a lot of plans to be realized on Earth after 10 months aboard the ship--a lot of things have happened without me,” Krikalev, who is scheduled to land Wednesday, said over a television link to the Flight Control Center. “I will need to look around and get used to many things during my first days--or maybe weeks--there. I will have to restore my normal physical condition and return to normal, everyday Earth life.”

The cosmonaut who rocketed up to the Mir last Tuesday to replace the 33-year-old flight engineer, Alexander Y. Kaleri, said this week that he doubts his comrade can conceive of how dramatically things have changed since he left Earth last May.

Just to mention a few of the high points: The Soviet Union has vanished, state socialism has been junked in favor of a market economy, and Wednesday’s landing should, juridically at least, occur in a foreign country--the former Soviet Kazakhstan.

Russian authorities allowed Western reporters to come to the ground control center in this normally off-limits town north of Moscow to talk to Krikalev and the four other cosmonauts now on Mir as the space station made an afternoon pass 250 miles over Russia.

During the question-and-answer session, Krikalev showed he was at least vaguely aware of what has happened in his absence.

“Our union had consisted of republics,” he said, his voice crackling from speakers in the control room here, his lean, handsome features visible on a large TV monitor. “Before the republics were united in the Union of Soviet Socialist Republics; now they join the Commonwealth of Independent States. Therefore, the changes might not be so dramatic as they appear at first glance.”

Well, perhaps. For even as Krikalev spoke, Commonwealth leaders were meeting in Kiev to try and thrash out fundamental issues that have bedeviled the post-Soviet republics since the day of its creation.

Krikalev, who is married and has one child, has become a personification of the grim hardships now buffeting Russia. He was supposed to be replaced in orbit last October but was forced to stay aloft when, for political and economic reasons, another flight engineer didn’t blast off.

“For a young father who has a 2-year-old son, taking such a decision was difficult. Nevertheless, he gave a positive answer,” Klaus-Dietrich Flade, a German air force pilot who along with Kaleri and flight commander Alexander S. Viktorenko docked Thursday with the Mir, has said in admiration.

Weightless in orbit, Krikalev and his comrades bobbed around in a bay of the Mir as they spoke before a camera that relayed their words and gestures to the Kaliningrad center. Behind them, they had draped Russian and German flags.

“Now, of course, we are in high spirits: Our friends have arrived,” Krikalev said. “There are five of us here now. There is more fun. Their arrival means that in a few days, we will complete our long tour here and head for Earth.”

For his TV appearance, Krikalev, whose uniform when he took off had a Soviet flag sewn to it, donned a white sweat shirt emblazoned with the logo of the joint Russian-German mission. His black hair had been neatly cropped by his commander, Alexander A. Volkov, and he smiled readily.

With the Soviet Union’s demise, what had been the world’s busiest space program, with 100 or more launches annually, faces an uncertain future. Cosmonauts are not prone to public griping, yet Volkov on Friday complained that the number of experiments scheduled for Mir missions has been cut.

There has been widespread speculation that the forced extension of Krikalev’s space flight has made him ill or depressed. Krikalev himself “laughed at such rumors,” and said a checkup before a February spacewalk found him in good health.