This morning’s Russian Soyuz rocket launch turned dire just two and a half minutes after liftoff when an unknown failure forced the flight to abort and sent the two astronauts on the vehicle on an unexpected landing. The emergency maneuver was a success, but the aftermath puts NASA in a precarious situation: now, the space agency must find a way to continue operations on the International Space Station without its usual equipment.

The Soyuz is currently the only vehicle that can take humans to and from the ISS, and the rocket is now grounded from human spaceflight for the foreseeable future. That means NASA may not be able to send astronauts to the station for a while, which could eventually leave the ISS without a crew.

“‘I hope they get down safe.’ that’s the only thing that was going through my mind.”

Fortunately, the two-person crew on board today’s flight was able to land safely. NASA astronaut Nick Hague and Russian cosmonaut Alexey Ovchinin took off in the Soyuz from Baikonur Cosmodrome in Kazakhstan at 4:40AM ET. Just a few minutes after launch, they experienced an issue with the Soyuz vehicle right around the time of first stage separation, which is when the four boosters surrounding the main body of the rocket break away. The duo was about 31 miles high, just below the threshold of space. Immediately, the Soyuz capsule initiated its abort sequence, separated from the rest of the rocket, and performed a ballistic reentry — when a vehicle comes in much steeper than a normal descent. The pair then landed in Kazakhstan after pulling about 6.7 Gs.

“‘I hope they get down safe.’ That’s the only thing that was going through my mind at that moment in time when I was watching that play out in real time,” Reid Wiseman, NASA’s deputy chief astronaut said during a press conference about the failure. “When I heard the first calls from the crew, there was a huge sigh of relief.”

It’s unclear at this point what caused the failure, though Russia says it has already opened an investigation to determine the cause. “We have every confidence that our Russian colleagues will figure out what’s going on,” Kenny Todd, the ISS mission operations integration manager, said during the press conference.

But for now, NASA no longer has a method to get its astronauts to the space station, and the crew that is already on board the ISS has to come down eventually. Right now, there are three people aboard the station: NASA astronaut Serena Auñón-Chancellor, Alexander Gerst of the European Space Agency, and Russian cosmonaut Sergey Prokopyev. These three crew members only have one way to get home: the Russian Soyuz capsule that brought them there in the first place.

Their Soyuz, MS-09, has been docked with the ISS since June 8th, when the crew first arrived. However, Soyuz capsules can’t last in space forever. They’re only meant to remain in orbit for 200 days, so this vehicle will presumably need to come down by the end of December. It’s possible that this lifetime can be stretched to January, but at some point, the Soyuz will need to return to Earth, and it will probably have to carry its three-person crew.

The station could be left without any people on board

That leaves NASA and Russia in a sticky situation: the station could be left without any people on board. It wouldn’t be the first time the ISS has been unstaffed. The orbiting lab went for months at a time without crew when it was first being built in the late ‘90s, but back then, it was only a few modules strung together. Since November 2nd, 2000, the ISS has always had people on board, so this would be the first break in crew in nearly 20 years.

NASA is already looking at ways to avoid such a gap. “As a program, we’re going to look at what our options are to try to make sure we don’t have to de-crew station,” said Todd. “And that’s an ongoing thing that we always do when it comes to trying to manage the overall flight program: to ensure that we’ve got crews on board to do the jobs we need to get done.”

It’s possible that Russia could launch another empty Soyuz capsule to dock with the International Space Station, helping to extend the time of the current crew on board by another 200 days. Russia is already going through the motions to prepare a Soyuz vehicle and rocket combo for a planned launch of three crew members on December 20th. That is still moving forward and could possibly fly. The Soyuz rocket may be grounded from sending crew to the ISS, but the vehicle might be able to launch a capsule without crew as a test. Then, it could dock with the ISS and provide another lifeboat for the crew on board.

However, if that plan doesn’t pan out, NASA says it is ready for the possibility of an empty space station. “That’s something we’re always prepared for, in terms of being able to support not having a crew,” Todd said. He noted that the crew will be looking at some of the robotic systems, pumps, and other instruments to make sure that NASA can continue to manage the station from the ground in case there’s no one around to take care of it in space. “I feel very confident that we could fly for a significant amount of time,” Todd said. “Indefinitely could be a very, very long time. We’re not there because our goal is to get back up there and get on with the science and the research that we need to do.”

“our goal is to get back up there and get on with the science and the research that we need to do.”

NASA has been working for years on new ways to get its astronauts to the ISS. Through the space agency’s Commercial Crew Program, two private companies — SpaceX and Boeing — have been developing vehicles to transport astronauts to and from the ISS. Those vehicles are not ready to take up the mantle yet, though. The two companies are scheduled to conduct uncrewed test flights of their spacecraft starting early next year, during which their vehicles will launch and dock with the space station without people on board. If those tests are successful, then the companies will perform the first flights of their vehicles with crew in the summer.

But it’s a requirement for NASA that the space station is crewed when those initial test flights occur, according to Todd. “We want to have crew on board because we want them monitoring,” he said. “The fact of the matter is that the space station is a $100 billion international asset for the world. So we definitely — when we start talking about these demonstration flights — having a crew on board, being able to monitor these vehicles as they approach, it’s certainly a very important thing.”

That means the first flights of the Commercial Crew Program could be delayed if the ISS is evacuated. Todd said it was too early to speculate on how this will affect the program’s future. However, delays in the Commercial Crew Program would stretch the amount of time NASA remains reliant on the Soyuz vehicle. Currently, NASA pays more than $70 million for one seat on the Soyuz to get its astronauts to space. The Commercial Crew program is meant to end that financial arrangement, allowing American astronauts to launch on American-made rockets again. But if the Soyuz is out of commission for long and the space station has to be de-crewed, that means NASA won’t be able to test out its vehicles in order to get off of Russian technology.

“The good news is we’ve got some runway.”

Ultimately, NASA doesn’t seem that worried just yet, and Todd says there’s plenty of time until the next crew is supposed to launch in December. “We’re going to have to let that play out a little bit,” he said. “The good news is we’ve got some runway to allow the Russians to go do some of that initial work to see if they can’t get this narrowed down relatively soon.”

Perhaps the most immediate problem NASA has is rearranging the astronauts’ schedule. The space agency was set to perform two spacewalks over the next two weeks, and the now-grounded astronaut Hague was supposed to be involved in one of them. “We’ll have to go look at that plan closely to see what makes sense about the spacewalk,” Todd said.

Even though there’s a lot of work ahead, the overall mood at NASA seems to be one of relief after experiencing a harrowing morning. “The first thing I want to really stress overall is that this is, in my opinion, a good news story,” said Weisman, adding, “The crew is already back on the ground in Baikonur, and they’ve been reunited with their families.”

Rachel Becker contributed to this report.