NASA has a fine plan for deorbiting the ISS—unless Russia gets in the way

A little more than two years ago, Dmitry Rogozin, the bellicose former head of Russia's space agency, nearly brought the International Space Station partnership to its knees.

During his tenure as director general of Roscosmos, Rogozin was known for his bombastic social media posts and veiled threats to abandon the space station after Russia's invasion of Ukraine. Russian President Vladimir Putin tersely dismissed Rogozin in July 2022 and replaced him with Yuri Borisov, a former deputy prime minister.

While the clash between Russia and Western governments over the war in Ukraine has not cooled, the threats against the International Space Station (ISS) ended. The program remains one of the few examples of cooperation between the US and Russian governments. Last year, Russia formally extended its commitment to the ISS to at least 2028. NASA and space agencies in Europe, Japan, and Canada have agreed to maintain the space station through 2030.

It's this two-year disparity that concerns NASA officials plotting the final days of the ISS. NASA awarded SpaceX a contract in June to develop a deorbit vehicle based on the company's Dragon spacecraft to steer the more than 450-ton complex toward a safe reentry over a remote stretch of ocean.

"We do have that uncertainty, 2028 through 2030, with Roscosmos," said Robyn Gatens, director of the ISS program at NASA Headquarters, in a meeting of the agency's advisory council this week. "We expect to hear from them over the next year or two as far as their follow-on plans, hoping that they also extend through 2030."

Fighting through the tension

Roscosmos works in four-year increments, so Russia's decision last year extended the country's participation in the space station program from 2024 until 2028. Russian space officials know the future of the country's space program is directly tied to the ISS. If Russia pulls out of the space station in 2028, Roscosmos will be left without much of a human spaceflight program.

There's no chance Russia will have its own space station in low-Earth orbit in four years, so abandoning its role on the ISS would leave Russia's Soyuz crew ferry spacecraft without a destination. Russian and Chinese leaders have fostered closer ties in space in recent years, but China's Tiangong space station is inaccessible from Russia's launch sites.

The US and Russian segments of the ISS depend on one another for critical functions. The US section generates most of the space station's electricity and maintains the lab's orientation without using precious rocket fuel. Russia is responsible for maintaining the station's altitude and maneuvering the complex out of the path of space junk, although Northrop Grumman's Cygnus cargo craft has also demonstrated an ability to boost the station's orbit.

While Russia's space program would feel the pain if Roscosmos made an early exit from the space station, the relationship between Russia and the West is volatile. US and European leaders may soon give Ukraine the green light to use Western-supplied weapons for attacks deep inside Russian territory. Putin said last week that this would be tantamount to war. "This will mean that NATO countries, the United States, and European countries are fighting Russia," he said.

These statements could be more rhetorical saber-rattling from the Kremlin, but they underscore the cloud of tension that hangs over the International Space Station, even as astronauts and cosmonauts happily work together 260 miles (420 kilometers) above the Earth.

"If they choose not to extend, we'll have to take a look at what does that mean," Gatens said. "If the deorbit vehicle is ready, do we go ahead and bring it home? Do we have a way of continuing? Obviously, it presents a risk, and we'll have to think about what the implications of that are for us."

Assuming the space station's international partners will retire the laboratory as planned in 2030, the final deorbit maneuver could happen in early 2031. NASA would like to have the deorbit vehicle ready for launch in 2029, up to a year and a half before the space station's final plunge. If these dates hold, the final crew for the ISS would likely launch in late 2029 and remain aboard the complex for a year, then come home before the final deorbit burns to guide the massive lab back into the atmosphere.

Enlarge / Elements of the Russian segment of the International Space Station.
NASA

Ken Bowersox, NASA's associate administrator for space operations, said the agency's leaders have thought about their options if Russia decides to end its participation in the ISS program.

"A lot depends on what happens after the Russian team decides they're not going to go past 2028," he said a meeting of the NASA Advisory Council's human exploration and operations committee Tuesday. "Is that a hard cutoff, (where) they turn off all the lights and aren't providing even propulsion anymore? Or might they still provide propulsion, but we need to provide some other contribution to make up for that, or do they fly (their modules) away? That's the least likely—they fly their segment away. Whether or not it's a sharp cutoff, or whether they continue to provide some minimal level of support, that affects what we do quite a bit."

There's also a chance NASA might want to keep the ISS flying beyond 2030. The agency is helping fund several industrial teams designing privately owned space stations, and NASA would like to have one of these commercial outposts in orbit when ISS falls out of orbit. This would give NASA and other customers a platform for continued research in low-Earth orbit.

NASA finds itself in a delicate balance here. As long as the ISS is operating, developers of commercial space stations may not find enough demand to close their business cases. Retire the ISS in 2030, and NASA risks a gap in research in low-Earth orbit as the agency pivots to flying astronauts to the Moon and eventually Mars.

“Our main goal is to avoid any type of separation between ISS and the platform that comes next," Bowersox told reporters in July. "We'd love to have some overlap, but there's lots of things that can keep us from being able to do that. Resources is one. Development schedule for the new vehicles is another. We’re going to make sure they're ready before they fly, and we wouldn't want to hurry them up.

"And then just how things are going with ISS, that's another possible factor," Bowersox continued. "So we'll be weighing all those things and doing our best to minimize any type of separation between the current platform and the platforms that come next ... We're thinking a lot about the transition. We're trying to manage it to minimize any type of disruption, and we'll use all the flexibility that we've got to avoid a disruption, but we'll have to react a little bit to how the situation actually develops.”