Since 1993, Mir and the ISS have fought like warring siblings for Russia’s dwindling space budget. When Boris Yeltsin and Bill Clinton agreed to build the space station, Russia promised to construct key modules and deliver other goods. Meeting those commitments has been difficult–especially since Mir required funding, too. After years of delays, however, Russia hit a high note in the international project last November. Two cosmonauts and an astronaut opened the station for business, and it seemed almost as though the most difficult period of the project was over. That’s not likely. Now that Russia is finally turning its undivided attention to the new station, the tough negotiations over day-to-day operations are just beginning. “We’ve gone through the courtship phase and now it’s time to really be married,” says NASA head Dan Goldin. “As with all new marriages, there will be bumps in the road.”

Although the International Space Station is supposed to usher in an era of cooperation, many Russians are already disgruntled about NASA’s dominance in the project. In many ways, the ISS pours salt in the wounds left by Mir’s demise. The problem is that Russia’s space funding had dried up over the past few years, while NASA held its own (aside from the Bush administration’s proposed cuts) during the U. S. economic boom. “NASA is the power and the money behind the ISS,” says Jeffrey Manber, president of MirCorp. In the past 18 months, Manber’s company has been working with the Russian Space Agency to broker commercial ventures that would save the Russian space station. Now, with Mir gone, “Russians must play second to someone else. That hurts their pride,” Manber says.

The ISS is even less exciting to Russians because they’ve already been living in space for years. Cosmonauts who’ve spent their careers operating Mir would rather go to Mars or build an outpost on the moon than sit around in low Earth orbit for another few decades. “Russia learned to dock cargo and manned ships to orbital stations 30 years ago. This is not a new development for us,” says former cosmonaut Anatoly Artsebarsky. The Russians might look forward to growing proteins and testing semiconductors in microgravity, but they won’t get much of a chance to do these things on the ISS. Three years ago cash-strapped Russia had fallen way behind schedule in building modules for the space station. NASA came to the rescue with $60 million–but in return asked for much of Russia’s crew and research time during the first phase of the project. As a result, Russian scientists will have to wait years before they can design and run their own experiments.

In the meantime, Russia is still struggling to finance its part of the international collaboration. The Russian Space Agency and Energiya, the quasi-private company that builds many of the country’s spaceships and rockets, hope to cash in on space tourism. American billionaire Dennis Tito offered to pay MirCorp $20 million last year in exchange for cosmonaut training and the chance to fly on Mir. Now Tito has signed a new contract with the Russians to travel to the International Space Station aboard a Russian Soyuz rocket. NASA couldn’t be less excited. The agency worries that space tourists like Tito will distract the crew at a crucial point in space-station assembly. However, NASA doesn’t have veto power over Tito’s mission: ISS rules give Russia sole authority to choose its crew members. Cosmonaut Talgat Mousabayev, who is scheduled to command Tito’s flight on April 30, doesn’t see why NASA is raising such a fuss. “Eighty years ago everyone was wondering how it would be possible to take a passenger aboard an airplane,” he says. “Cosmic transport is just the next step. It’s absolutely logical.”

Whether or not Tito actually flies in April, NASA will eventually have to tolerate tourism and media ventures on the ISS. America’s NBC TV is working on a deal with MirCorp, which is 60 percent owned by Energiya. NBC hopes to run a televised competition, based on CBS’s hugely popular “Survivor” series, in which the winner gets a trip aboard the ISS. And the American company Spacehab, which has flown storage and research equipment on U.S. shuttle flights for years, is building Russia’s next module in partnership with Energiya. The module could support everything from docking ports and crew quarters to commercial research and multimedia ventures. The module could also host tourists, if NASA and Russia ever work out their differences on space visitors.

Despite their marital spats, neither party can afford to pull out now. Americans need Russian expertise in space-station operations. The U.S. government also hopes that work on the ISS will keep Russian rocket scientists and engineers from selling their services to rogue states. The Russians have their own financial reasons to stick it out. In the initial space-station agreement, President Clinton allowed Russians to sell a limited number of rockets to American commercial satellite companies. As long as Russia continues to pocket hundreds of millions of dollars each year from those sales, ditching the space station would be bad economics.

Even if Russia holds up its end of the ISS deal, what about NASA? Recent budget cuts and cost overruns have raised questions about whether the Americans will be able to fund the project to completion by the target date of 2005. At least one company isn’t taking any chances. Jeffrey Manber says MirCorp is designing a manned module that could operate independently of the international station. Due to international financial woes, Manber says, the space station may not be the most profitable space property of the future.

Of course, politics and budget problems are a way of life in a huge international project. Despite all odds, space-agency officials are trying to look beyond the tough negotiations to the advances they believe the ISS will yield. “The time when we tried to gain superiority [has] passed,” says cosmonaut Vasily Tsibliyev. “It’s now time for us to work together.” Tsibliyev hopes that the ISS will eventually become a launching pad for a mission to Mars. It’s possible, if the United States and Russia can find a way to conquer their post-honeymoon troubles and make this partnership last.