Two cosmonauts stepped off a bus at the Baikonur Cosmodrome — the Soviet Cape Canaveral — ready to ride a 10-story Soyuz rocket into orbit. This launch complex in the heart of Kazakhstan had sent the first satellite, animal and human (Sputnik, Laika and Yuri Gagarin) into space. It was the spring of 1991, three decades after Gagarin’s historic flight, and Sergei Krikalev and Anatoly Artsebarsky were there to follow in his footsteps. But first, they kept up the tradition Gagarin had started back in 1961. The men marched to the right rear tire of the bus, unzipped their spacesuits and started urinating. Then, they headed for the launch pad.

To the world, space travel had become routine. American astronauts had flown dozens of space shuttle missions, and Soviet cosmonauts were building ever more complex space stations, culminating with Mir, Artsebarsky and Krikalev’s destination. Few eyes glanced skyward that day, nor would they in the months ahead — events on Earth would soon distract the world and set a new course for manned spaceflight that continues today.

After blasting off from Baikonur, Krikalev wouldn’t inhale earthly air for 312 days. In that time, the soft-spoken cosmonaut would watch his country crumble from 200 miles up. Presidents would change. His hometown of Leningrad would become St. Petersburg. And one communist superpower would splinter into 15 nations. By the time he returned, Krikalev would be, in essence, the last remaining citizen of the once-mighty Soviet Union.

Cosmonaut Anatoly Artsebarsky, British astronaut Helen Sharman and Sergei Krikalev board a Soyuz rocket in Kazakhstan. ITAR-TASS Photo Agency/Alamy Stock Photo

But out of the chaos, NASA’s current trajectory also emerged. After the USSR collapsed, American politicians began working with Russia, hoping to take astronauts back into orbit with a space station, and eventually on to the moon and Mars. The international plan put a cosmonaut (Krikalev) on the space shuttle and an astronaut on Mir — and ultimately led to one of the highest-profile international collaborations of all time: the International Space Station (ISS).

May 18, 1991

Unlike Gagarin, Krikalev was no folk hero. Most of his countrymen didn’t know his name, and many still don’t. The famously humble cosmonaut doesn’t get political, and doesn’t seek the limelight. (For this story, he was unavailable for comment.) But by his late 20s, he was already an impressive pilot and a member of the Soviet Union’s national aerobatics team. When the Soviets lost contact with their Salyut 7 space station in 1985, Krikalev was on the ground control team that planned the audacious in-orbit rescue mission. That role helped win the young pilot his cosmonaut wings the next year. And by 1988, he’d already completed his first flight, a mission to the new Mir station.

Helen Sharman, the first Briton in space, launched with Artsebarsky and Krikalev from Baikonur on May 18, 1991 — Krikalev’s second trip. She remembers the cosmonaut as cool under pressure. As their spacecraft approached Mir, the targeting system failed. Her heart raced, knowing that a miss could be deadly. But Krikalev’s aim was flawless even without the rendezvous guidance, and they boarded Mir without issue, joining an existing crew.

Mir had a well-earned reputation as a smelly, noisy place. It was no bigger than a few RVs stacked end to end. Dozens of stowaway microorganisms lurked on board, and Mir had developed the distinct aroma of sweaty men locked in a small house with cognac. The constant racket from fans and pumps and other machinery was enough to cause hearing loss.

Mir in orbit. NASA

But to Krikalev, none of that mattered. “He always said when he got into the space station, he felt like he was going home,” Sharman later said in interviews. He loved the feeling of weightlessness and learned to fly like a bird from one side of the space station to the other without touching down — a rare feat. Most cosmonauts read to pass the time, but Krikalev and his crew spent their free hours looking out the window.

“Every spare moment, we tried to look at the Earth,” Krikalev told the media. He’d search the planet for places he’d been or heard about. After a scant eight days in orbit, Sharman went home with the two-member crew already on board, leaving Krikalev and Artsebarsky alone. The pair had a five-month mission packed with six spacewalks outside the station for upgrades and repairs.

But even from this vantage point, Krikalev had no way of seeing what was unfolding in his communist homeland — or how it would change his time aboard Mir. By summer, USSR President Mikhail Gorbachev’s policy of loosening control over the Soviet states had led many of them to push for independence. One of those states was Kazakhstan, home to the Baikonur Cosmodrome. To appease its government, Moscow’s leaders offered a spot on Mir to a Kazakh cosmonaut, taking the place of the more experienced cosmonaut who would have relieved Krikalev.

Cosmonauts Aleksandr Volkov and Krikalev work in the Mir space station. TASS/Sovfoto/Eastfoto

As a result, Krikalev would have to remain in space until further notice — those initial five months now stretched out indefinitely, despite the risks to his health. The effects of long-term spaceflight aren’t fully understood even today, but the cosmonaut faced at minimum an increased risk of cancer, cataracts, nasal congestion, muscle atrophy, bone loss, infection and even immune system problems.

Krikalev knew the dangers, and he later shared his concerns with the media. “Do I have enough strength?” he asked himself. “Will I be able readjust for this longer stay to complete the program? Naturally, at one point I had my doubts.”

August 19, 1991

As dawn broke, tanks rolled into Moscow’s Red Square. A coup d’état was underway. Gorbachev, on vacation at the time, had frustrated hard-liners with his reform attempts. Communist party leaders were determined to restore power. On Mir, as on Earth, details were hard to come by. An official announcement claimed Gorbachev had stepped aside voluntarily for health reasons, but many citizens took to the streets to protest the coup.

“For us, it was totally unexpected,” Krikalev later said. “We didn’t understand what happened. When we discussed all this, we tried to grasp how it would affect the space program.” Gorbachev recovered power within days, but the country’s fate was sealed. Over the coming weeks and months, the Soviet states declared independence one at a time.

Soviet tanks move near the Kremlin after a coup attempt in 1991. Anatoly Sapronyenko/AFP/Getty Images

During that time, Krikalev got semi-regular calls from his wife, Elena, who worked in mission control. The pair had gotten to know each other over the radio on his previous mission to Mir. This time, they had a 9-month-old daughter. As the political turmoil caused prices to surge at home, Krikalev wondered how his family was surviving with his meager pay of just a few dollars a month (a result of communist ethos and inflation).

“I tried never to talk about unpleasant things because it must have been hard for him,” Elena later told a documentary film crew. “As far as I can make out, Sergei was doing the same thing.”

October 2, 1991

As Krikalev’s original stay neared its close, a new team of three cosmonauts joined the Mir crew. None had the flight experience to replace him, but at least Austrian Franz Viehböck was packing lemons for the stranded cosmonaut; he found them at a tourist shop for Westerners. Then, after just a week, the Austrian returned home, taking Artsebarsky and another of the new three cosmonauts back to Earth with him.

The longer Krikalev stayed in orbit, the more scarce Russia’s cash became. The collapsing country sold off space station trips to Western governments to raise funds. There were even discussions about selling Mir itself, which made the crew wonder about their status as tenants. “A human race sent its son off to the stars to fulfill a concrete set of tasks,” reported the Komsomolskaya Pravda. “But hardly had he left Earth than it lost interest in those tasks, for worldly and completely explicable reasons. And it started to forget about its cosmonaut. It did not even fetch him back at the appointed time, again for completely worldly reasons.”

Krikalev and Volkov share a meal aboard Mir in February 1992. TASS/Sovfoto/Eastfoto

There was a Soyuz capsule Krikalev and his comrade, Ukrainian Aleksandr Volkov, could use for a hasty escape, but if they took the easy way out and left Mir, it could mean the end of the space station. And so they stayed.

December 25, 1991

The Cold War and the Soviet Union ended on Christmas Day. And yet President George H.W. Bush was concerned. “We stand tonight before a new world of hope and possibilities and hope for our children, a world we could not have contemplated a few years ago,” he told the nation in a Christmas speech. “The challenge for us now is to engage these new states in sustaining the peace and building a more prosperous future.”

Bush was right to worry. In the former Soviet states, some of the world’s greatest rocket scientists now struggled to feed their families. Countries like Iran, India and North Korea were eager for their services. American officials wanted to put Russians back to work in hopes of propping up the fragile democracy. Behind the scenes, the former rivals started crafting a deal that put American taxpayer dollars into Russian rocketry and spacecraft, keeping up operations in orbit. Krikalev was willing to sacrifice his own health and happiness for that same cause.

“They say it’s tough for me — not really good for my health."

“The strongest argument was economic because this allows them to save resources here,” Krikalev said from orbit. “They say it’s tough for me — not really good for my health. But now the country is in such difficulty, the chance to save money must be (the) top priority.”

Jeffrey Manber worked on space commerce issues for the Reagan administration and later negotiated the contract for the first space tourist, Dennis Tito. Manber was soon the only American working in the Soviet space industry, and he eventually hand-delivered the first U.S.-Soviet space contract. “There was a good deal of chaos,” Manber recalls. “There was a good deal of fear. Institutions were crumbling. No one knew what the future would bring.”

March 25, 1992

Finally, Krikalev got word that he would be replaced and could return to Earth. The last Soviet citizen landed near the city of Arkalyk in the now-independent Republic of Kazakhstan. Krikalev had circled the Earth some 5,000 times, and seen as many sunrises and sunsets. In the decades to come, he’d log 803 total days in orbit. No one would spend more total time in space until his comrade Gennady Padalka in 2015 — and that was on purpose.

Krikalev emerges from a Soyuz capsule in March 1992. TASS/Sovfoto/Eastfoto

Once back on terra firma, a group of four men helped Krikalev down from the Soyuz capsule. He was pale as flour and sweaty, like a lump of wet dough. One man fanned his face with a handkerchief. Another handed him hot broth. Fresh air and burning sunlight washed over his body, which was nestled beneath a fur coat. A blanket of fresh snow made it tough to walk.

“It was very pleasant in spite of the gravity we had to face,” Krikalev recalled years later for a documentary crew. “But psychologically, the load was lifted. There was a moment. You couldn’t call it euphoria, but it was very good.” The enormous responsibility of managing Mir was no longer his. It would take weeks for Krikalev to feel normal back on the ground and months to recover fully.

In his understated way, Krikalev downplayed the significance of his trip once back on Earth. His own people didn’t know his name and face, but many journalists would ask him about returning to a changed planet.

“What surprises me most?” he mused to reporters. “That at first, the Earth was dark, and now it’s white. Winter has come, and before it was summer. Now, it’s beginning to bloom again. That’s the most impressive change you can see from space.”

June 17, 1992

Months after Krikalev’s return, President Bush and Russian President Boris Yeltsin met in Washington, D.C., and finalized the Shuttle-Mir program, which put cosmonauts on the space shuttle and astronauts on Mir, paving the way for the ISS. Krikalev returned to training almost immediately, traveling to America to prepare for his role as the shuttle’s first Russian crew member in 1994, flying alongside current NASA Administrator Charles Bolden.

“After meeting, training and flying with Sergei, I had great hopes that U.S.-Russian relations in space would develop progressively and that one day Russians and Americans flying together with astronauts of other nations would become commonplace,” Bolden says.

The birth of the ISS: Unity and Zarya nodes meet in 1998. NASA

Not long after, the U.S. and Russia combined their orbiting laboratory efforts toward the ISS. But the Russians fell through on their funds, leaving the U.S. to pick up the tab, or risk dropping the project altogether. The Clinton administration thought it was worth the cost just to help prop up the fledgling country. “The deal was done because of the collapse of the Soviet regime,” says author and expert on Soviet-Russian space James Oberg. “Prior to that, there were institutional and cultural barriers. There were informational barriers.”

Zarya, built in Russia with American dollars, would become the ISS’s first module, or major component. Krikalev and his shuttle crew were tasked with mating Zarya to Unity — the first American-built module.

With this new collaboration in 1998, the ISS was born — and Krikalev was back “home” in space.

Epilogue: Present Day

Krikalev returns to the newly assembled ISS as Expedition One flight engineer in 2001. NASA

The International Space Station has now traveled 2.6 billion miles during its more than 100,000 orbits. That’s nearly far enough to reach Neptune, the outermost planet. But since retiring the space shuttle in 2011, Americans have paid Russia’s space agency Roscosmos billions of dollars for rides into orbit. NASA Administrator Charles Bolden had hoped to end that dependence in 2017­— two years later than planned — with private company SpaceX taking its first astronauts to the ISS, followed by Boeing the year after.

But even that delayed timetable now looks unlikely. A SpaceX Falcon 9 rocket exploded in August just as NASA’s Office of Inspector General reported that, in addition to congressional underfunding, bureaucratic sluggishness could push American ISS launches back to 2018. That’s the last year Russia’s agreed to send American astronauts.

“The ISS has become the critical toehold in the future exploration of our solar system,” Bolden says. The way he sees it, NASA’s endeavors in orbit teach us how to survive in deep space. Even though the aging station will likely outlive its useful life span by 2024, American companies hope to build its successor by mounting capsules to the ISS that could eventually serve as private space stations.

Space entrepreneur Jeffrey Manber runs NanoRacks, a company that deploys small satellites and offers space services, like lab equipment, on the ISS. He traces today’s commercial space exploration era to NASA’s willingness to pay others for services after the Cold War.

Manber points out that some American companies — plus Russia and China, which launched a space station in September — will soon have their own astronauts. Those travelers will need new space stations. “We’re moving into a very exciting era,” he says.

For Bolden’s part, he sees a future space station as the foundation of a journey to Mars and beyond. He says that will depend on continued international cooperation. And with today’s chilling of U.S.-Russian relations, those partnerships could also prove as important to earthly affairs as they were in the past.