With three crewed launches under its belt, SpaceX has now flown astronauts representing not only NASA, but also the European and Japanese space agencies. But there's a glaring absence: Russia.
Despite months of ongoing negotiations, NASA and its Russian counterpart, Roscosmos, have yet to agree on a system for exchanging seats on rides to the International Space Station. Under such a scheme, NASA astronauts would continue to fly on Russian Soyuz vehicles and Russian cosmonauts would step aboard U.S. commercial vehicles like SpaceX's Crew Dragon. It's a system NASA has loudly endorsed while waiting for the first commercial vehicles to reach the launch pad, and it isn't clear whether there are any substantive disagreements slowing the negotiations.
"Of course we would be honored to fly cosmonauts on Dragon, but I do not have any insight into any potential objections," SpaceX founder Elon Musk said during a news conference held April 23 after the successful launch of the Crew-2 mission. "Perhaps this may just be a communications breakdown, I don't know."
NASA meanwhile is emphasizing that an agreement is in the works and that such international negotiations are simply slow by nature.
"We're working through the agreements right now," Kathy Lueders, head of NASA's Human Exploration and Operations directorate, said during the same news conference. "People understand the importance of crew swaps for supportability of ISS and so we're working through that and getting that agreement in place. It takes a while sometimes, I've found out, there's lots of people to coordinate with so it doesn't happen as fast probably as I want it to, but we're working through it."
In early February, acting NASA Administrator Steve Jurczyk told Space.com that he thought Russia would require three Crew Dragon missions to be safely completed before putting a cosmonaut on board, but that he hoped an arrangement could be reached in time for a Russian cosmonaut to fly on Crew-3, which will launch in October.
But that's likely no longer a possibility given how long flight preparations take, Jurczyk said during a news conference held April 21 in preparation for the Crew-2 launch.
"We haven't completely given up on having a cosmonaut on Crew-3," Jurczyk said. "But at this point, given the schedule, it'd be really, really challenging to complete all the training, get the suit fitted and done for a cosmonaut on Crew-3."
NASA typically aims to assign astronauts to missions between 18 months and 24 months before launch, but can accelerate the process depending on a specific astronaut's flight qualifications.
Currently, Crew-3 includes NASA astronauts Raja Chari and Tom Marshburn and European Space Agency (ESA) astronaut Matthias Maurer. SpaceX's Crew Dragon can accommodate up to seven astronauts at a time, but the capsules are currently configured to have only four seats. Meanwhile, SpaceX's following mission, the Crew-4 flight scheduled to launch in 2022, still holds two empty seats.
In addition to Russian cosmonauts, ESA astronaut Samantha Cristoforetti is a candidate to fill one of these three empty seats. ESA has said she will be its next astronaut to fly on a commercial crew vehicle, but the agency has not specified whether she will launch with SpaceX or Boeing, which is also building a crew vehicle for NASA.
Throughout the International Space Station's tenure, the U.S. and Russia have been the only two of the five partners behind the endeavor capable of carrying their own astronauts to orbit: crewmembers hailing from Canada, Japan and the countries that make up the European Space Agency (ESA) have always hitched a ride.
Russia has used its workhorse Soyuz capsule with occasional modernizing upgrades to carry crewmembers to orbit. NASA, in contrast, entered the space station era with its fleet of reusable space shuttles, then spent nine years grounded while commercial partners developed their own vehicles to carry crewmembers to and from orbit.
During that time — and prior, in the wake of two fatal shuttle failures — NASA astronauts hitched rides to space aboard Russia's Soyuz. Meanwhile, more than a dozen cosmonauts launched on space shuttles before that program's retirement in 2011.
But as NASA's commercial vehicles have developed, the agency has emphasized that it wants to ensure the crew of every mission to the space station includes representatives of both major partner nations. That's because the station is split into two orbital segments, so if either Russia or the U.S. loses presence in orbit, its side of the laboratory would be left empty.
So NASA wants its astronauts continuing to fly on Soyuz capsules and Russian cosmonauts to become passengers on new American commercial vehicles. And finally, those commercial flights are beginning. But so far, Russia has hesitated to take part.
The first American commercial vehicle, SpaceX's Crew Dragon, made its first crewed flight in May 2020. It is currently wrapping up its first full-fledged, six-month mission, Crew-1, which will end when four astronauts splash down on Saturday (May 1), or perhaps later if weather conditions interfere; its second such mission launched last week, marking the first time two crewed commercial vehicles have been simultaneously docked to the space station.
The second vehicle, Boeing's CST-100 Starliner, has been plagued with delays since a December 2019 uncrewed test flight failed to reach the space station and landed early; at best, it will fly a crewed test mission late this year.
For months, NASA has said that it is working with Russia to negotiate a seat exchange agreement to guide astronaut flights moving forward. Since the space shuttle's retirement, NASA has purchased its seats from Roscosmos in batches; most recently, NASA astronaut Kate Rubins launched in October on a one-off seat that cost NASA $90 million.
Her seat was widely touted as the last NASA would buy from Russia before implementing seat exchanges. Technically, that has held true: Although NASA's Mark Vande Hei launched aboard a Soyuz earlier this month without the outstanding agreement, NASA arranged for his seat with the Texas-based company Axiom Space, promising to fly someone selected by the company in 2023, rather than paying any money for the seat.
But there's still no firm plan for what comes next in U.S.-Russian spaceflight.
Seat-exchange negotiations began under former NASA Administrator Jim Bridenstine, who resigned from leading the agency on Jan. 20 as President Joe Biden took office. In a late February call with Jurczyk that included discussion of crew flight arrangements, Roscosmos director Dmitry Rogozin invited a NASA delegation to attend the April 9 Soyuz launch, according to a Roscosmos statement released at the time.
According to a separate Roscosmos statement, Rogozin met with Ken Bowersox, NASA's deputy associate administrator for human exploration and operations, in Kazakhstan in conjunction with the April 9 Soyuz launch of Vande Hei and two Russian cosmonauts. NASA did not respond to a request for details about agency personnel who attended the launch.
Rogozin's feelings on seat exchange are unclear: He has stalwartly defended the Soyuz capsule's long and remarkably clean flight record, particularly in comparison to the shuttle program, which NASA grounded in part due to reliability concerns. Meanwhile, he has expressed skepticism at the cost of American launch programs, and before an uncrewed test flight of Crew Dragon in 2019, Russia expressed concerns about the safety of the vehicle's systems as it approached the space station for docking.
NASA hasn't offered any details about the ongoing discussions or any potential sticking points between the two countries, only emphasizing its confidence that the discussions will succeed. "We're looking forward to getting the implementing agreement, the final sign off from the State Department and getting that draft to the Russians and negotiating the crew swap," Jurczyk said on April 21.
Meanwhile, NASA can't even be sure right now what timeline it's working with.
The agency's primary goal with seat exchanges is to ensure that if something goes wrong with the SpaceX flight program before Boeing's Starliner is ready to launch, the agency can still have at least one astronaut in orbit at all times. But it isn't clear yet how long Vande Hei will remain in orbit.
A typical flight schedule would see him stay in space for a little more than six months, returning perhaps in October. But previous Roscosmos announcements suggest the autumn Soyuz launch to the station might carry two visitors for a short stay, an actress and a director for a film production to be shot in orbit. If that schedule holds, Vande Hei would miss the next seat home and be left in orbit for nearly a year all told, easing NASA's immediate fears about space station staffing.
Meanwhile, the agency is also waiting for its second flight option from the U.S. in the form of Starliner. That vehicle's next mission will launch no earlier than August, when Boeing will make a second try at an uncrewed test flight to the space station. The first such flight, launched in December 2019, didn't reach the station and landed early after software glitches that NASA and the company have spent the intervening months trying to fix.
If the second uncrewed flight goes smoothly, it's time for Starliner to carry humans on a crewed test flight. That mission is currently on NASA's schedule for September despite the continuing delays to the uncrewed launch.
Email Meghan Bartels at firstname.lastname@example.org or follow her on Twitter @meghanbartels. Follow us on Twitter @Spacedotcom and on Facebook.
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Meghan is a senior writer at Space.com and has more than five years' experience as a science journalist based in New York City. She joined Space.com in July 2018, with previous writing published in outlets including Newsweek and Audubon. Meghan earned an MA in science journalism from New York University and a BA in classics from Georgetown University, and in her free time she enjoys reading and visiting museums. Follow her on Twitter at @meghanbartels.