Stranded in Space? NASA Doesn’t See the Starliner Astronauts That Way.

If you go somewhere expecting an eight-day trip and end up not being able to leave for eight months, most people would consider that “stranded.”

That is what has happened to Suni Williams and Butch Wilmore, two NASA astronauts who traveled to the International Space Station in June aboard Boeing’s Starliner spacecraft. During the test flight, the propulsion system malfunctioned, and engineers are not certain it would bring the two astronauts back to Earth alive.

So doesn’t that mean the astronauts are stranded?

Delian Asparouhov, a founder and the president of Varda Space Industries, which aims to manufacture drugs and other materials in space, posted on X: ”I don’t know about you, but if I got stuck at an airport for seven months longer than expected, that would definitely qualify as ‘stranded.’”

But for astronauts who spend their careers hoping to travel to space, extra time in orbit — now 10 weeks and counting — is not a nightmarish struggle for survival as it is for Matt Damon’s marooned astronaut character in the movie “The Martian.”

Indeed, it might be more like your boss asking if you would mind extending a short business trip to Paris by half a year.

“Butch and I have been up here before, and it feels like coming home,” Ms. Williams, who has had two previous long stays on the space station, said during a news conference last month. “It’s great to be up here, so I’m not complaining.”

Whether Ms. Williams and Mr. Wilmore are stranded or not, NASA now faces a difficult decision it needs to make within the next week or so about the safest way to bring them back to Earth.

If it decides the problems with Starliner’s propulsion system pose too great a risk, NASA will switch to a backup plan, bringing the two astronauts home on Crew Dragon, a vehicle built by Boeing’s rival, SpaceX.

That, in turn, will lead to a juggling of astronaut assignments for the space station. The next Crew Dragon, scheduled to launch in late September, would take two astronauts to the space station instead of four, leaving two seats for Ms. Williams and Mr. Wilmore on the return trip around February of next year.

All summer, NASA and Boeing officials have been reluctant to use the words, “stuck” and “stranded,” which would add another black mark to a spacecraft that has been delayed for years by technical setbacks.

“I think reporters use imprecise language to get viewers,” said Lori Garver, who served as the deputy administrator of NASA during the Obama administration. “We’re all used to that. I don’t think it’s worth being defensive about, but they’re also not really stranded.”

For one, though NASA and Boeing did say Starliner would spend at least eight days at the space station, officials point out this is a test flight designed to uncover problems. Thus, they say, it is not a surprise that not everything has gone perfectly.

“I think we all knew that it was going to go longer than that,” said Mark Nappi, the Boeing official in charge of the Starliner program. “We didn’t spend a lot of time talking about how much longer, but I think it’s my regret that we didn’t just say ‘We’re going to stay up there until we get everything done that we want to go do.’”

The reasons for the astronauts’ extended visit — or stranding, if you prefer — involves 28 thrusters known as the reaction control system that Starliner uses for maneuvering. During its approach to the space station, five of them malfunctioned. Though four were revived, and Starliner safely docked, there remained concerns that they might fail again on the return trip.

Ground testing showed that the problem might have been caused by the expanding of a Teflon seal within the thrusters, constricting the flow of propellant.

But subsequent test firings of Starliner’s thrusters in orbit showed that the performance had returned to almost normal. That was puzzling, because a distorted Teflon seal would not be expected to return to its original shape. That raised the possibility that something else was the cause of the thruster problems.

Joseph Fragola, an aerospace safety expert who has not worked on Starliner but did work with similar thrusters on the lunar lander during the Apollo program in the 1970s, said that an imbalance of the propellants could lead to a buildup of gunk within the thrusters. That too would explain the diminished performance of the thrusters, and the residue could later evaporate, explaining why the thrusters now work normally.

“I don’t know if that’s the problem they’re having, but it took us a long time to fix that problem,” Mr. Fragola said.

If that is an issue, it could pose a serious danger. The residue and an unbalanced mixture of propellants could set off an explosion, Mr. Fragola said.

NASA officials offer another reason to support their assertion that Ms. Williams and Mr. Wilmore aren’t truly stranded: They remain confident enough in Starliner that two astronauts would use it in case of an emergency evacuation of the space station.

That was not the case in December 2022, when the radiator of a Russian Soyuz capsule sprang a leak and all of the vehicle’s coolant floated into space. A NASA astronaut, Frank Rubio, had traveled to the space station on the Soyuz, and NASA officials decided that the damaged spacecraft was not safe enough for an emergency because temperatures inside during re-entry might grow fatally hot. At that time, a jury-rigged seat was added for Mr. Rubio in a Crew Dragon that was also docked at the space station.

Mr. Rubio was arguably stranded at the space station until Russia sent a replacement Soyuz. He had been scheduled to spend six months at the space station, but he ended up setting the record for the longest single stay in orbit by an American astronaut: 371 days.

The extended stays for Ms. Williams, Mr. Wilmore and Mr. Rubio may have been unplanned, but not uncomfortable, with plenty of supplies brought up by cargo spacecraft.

That was not the case in 2003 for Don Pettit, an astronaut who is currently in Russia preparing for his fourth spaceflight, a launch to the space station scheduled for Sept. 11. During his first spaceflight two decades ago, he was one of three astronauts on the space station when the space shuttle Columbia disintegrated during re-entry.

Mr. Pettit, along with Ken Bowersox of NASA, who is currently a top NASA official overseeing Starliner’s plight and was then the commander of the I.S.S., and Nikolai Budarin, a Russian astronaut, were in no immediate danger.

But as the three crew members grappled with the deaths of seven NASA astronauts — their friends and colleagues — Mr. Pettit and Mr. Bowersox also quickly realized that the shuttle Atlantis, which was to pick them up the following month, was not arriving anytime soon. They began rationing supplies.

“We were immediately on a water shortage and a food shortage and a clothing shortage, and we extended the best we could these supplies,” Mr. Pettit said during an interview on Friday.

In a NASA interview in 2015, Mr. Pettit said there were more than enough supplies there. But no one knew how long the shuttles would remain grounded.

“It’s like you’re sitting on a mountain of food and clothing, and you’re starting to ration these things out, not because you need to for your mission, but you’re doing that to extend other people’s missions,” Mr. Pettit said.

There are no washing machines in space, so clothes are worn for a few days, then used as rags, then thrown out. Mr. Pettit said the astronauts began wearing their clothing longer than planned.

“The indicator that it was time to change your underwear would be when you started to get a rash around your waist,” Mr. Pettit said.

Mr. Pettit and his crewmates finally returned to Earth in May 2003 on a Russian Soyuz spacecraft — three months later than planned.