NASA has decided it’s too risky to have Boeing’s Starliner spacecraft return to Earth from the International Space Station with its two crew members, and so those astronauts will extend their stay by several months and come back on a SpaceX Dragon capsule instead. Starliner, which has been in the midst of its first crewed flight after years of delay, will be reprogrammed to make an uncrewed departure from the space station next month.
Top mission managers said today that they decided unanimously to make a dramatic change in what was originally expected to be a test flight lasting only a little more than a week. They said there was too much uncertainty surrounding the thruster problems that arose during Starliner’s trip to the station in early June.
“All of us really wanted to complete the test flight with crew, and I think unanimously we’re disappointed not to be able to do that,” said Ken Bowersox, NASA’s associate administrator for space operations.
NASA Administrator Bill Nelson said Boeing “worked hard” to address questions about the thruster system, but in the end, the space agency took what it considered to be the safer course. He said NASA learned its lessons from “mistakes done in the past,” including safety lapses that led to space shuttle disasters in 1986 and 2003.
“Our core value is safety, and it is our North Star,” Nelson said.
How things went wrong
For more than two months, NASA and Boeing have been working to figure out why five of the 28 maneuvering thrusters on Starliner’s service module malfunctioned during the spacecraft’s approach to the space station.
“It’s been a long summer for our team,” said Steve Stich, manager of NASA’s Commercial Crew Program.
Engineers determined that the thrusters experienced overheating that was above what they were designed to face, and on-the-ground tests showed that such conditions could cause Teflon seals in Starliner’s oxidizer lines to swell up, reducing the thrusters’ performance.
Stich said temperatures within a housing for the thrusters, known as a “doghouse,” became “hotter than we thought.” The heating effects from a different set of thrusters added to the concerns, he said. “There was just too much uncertainty in the prediction of the thrusters,” Stich said.
The concern is that something could go awry when the thrusters are used to maneuver Starliner for its descent from orbit, and that the crew members wouldn’t be able to do a course correction in time.
Amid the mounting concerns, mission managers developed a contingency plan that called for Butch Wilmore and Sunita Williams, the two astronauts who rode Starliner up to the space station in June, to remain in orbit and join a slimmed-down crew that’s due to launch in a SpaceX Dragon next month. Wilmore, Williams and two other astronauts would return to Earth next February.
Stich said the debate over whether to put Wilmore and Williams on Starliner or extend their orbital stay was spirited. “There was just a little disagreement as to the level of risk,” he said. But after the dissenting views were heard, top managers went with the SpaceX option.
How the backup plan will work
In the days ahead, NASA will run through a rehearsal for having Starliner undock from the space station under remote control. The uncrewed craft’s departure date will be scheduled after that rehearsal, most likely sometime in early September, with touchdown planned at White Sands Space Harbor in New Mexico. Update for Aug. 29: NASA and Boeing mission managers have scheduled Starliner’s departure for no earlier than 6:04 p.m. ET (3:04 p.m. PT) Sept. 6, which would lead to a New Mexico touchdown at 12:03 a.m. ET Sept. 7 (9:03 p.m. PT Sept. 6).
A SpaceX Dragon that’s currently docked to the station will be reconfigured to accommodate Wilmore and Williams in the event of an emergency. And the next Dragon crew-rotation mission, which is set to launch no earlier than Sept. 24, will carry two astronauts instead of the previously planned four. Two of the seats on that Dragon will be designed to fit Wilmore and Williams, and ballast will be added to represent their weight on the way up. The Dragon will also bring up an extra SpaceX spacesuit, to supplement a spare suit that’s already on the station.
In a posting to the X social-media platform, SpaceX President Gwynne Shotwell said that “SpaceX stands ready to support NASA however we can.”
Dana Weigel, NASA’s International Space Station program manager, said Wilmore and Williams will continue to help out on the space station while they wait for their ride home. “We may have a couple of spacewalks for them toward the end of their expedition,” she said. “Since they’ve been up there, they’ve been a welcome set of helping hands. They’ve already done about 100 hours of work on 42 different experiments, and they’ve helped us with some of the critical station maintenance that we’ve had on board.”
Norm Knight, NASA’s flight operations director, said the astronauts are handling the delays with professionalism.
“When they launch, they know that there are circumstances where they can be on board for up to a year,” he said. “So, mentally, you know that you could be in that situation. Now, once you’re in the arena, obviously it’s a little different. It’s challenging. It’s disappointing that they’re not coming home on Starliner. But that’s OK. It’s a test flight. That’s what we do.”
The delay means Wilmore and Williams will end up spending eight months in orbit, including Thanksgiving, Christmas and New Year’s Day.
What’s next for Boeing?
Nelson said he broke the news about the change in plan to Boeing’s recently named CEO, Kelly Ortberg. “I told him how well Boeing worked with our team to come to this decision, and he expressed to me an intention that they will continue to work the problems once Starliner is back safely, and that we will have our redundancy and our crew access to the space station,” Nelson said.
Certifying Boeing’s Starliner is a key part of NASA’s strategy of having at least two types of commercial spacecraft available for trips to orbit. That strategy provides redundancy in case one type of spacecraft has to be sidelined.
Under the terms of NASA’s $4.2 billion fixed-price contract, Boeing is required to cover any extra development costs for Starliner. So far, Boeing has had to cover roughly $1.6 billion in cost overruns.
In a posting to X, Boeing said it would “continue to focus, first and foremost, on the safety of the crew and spacecraft.”
“We are executing the mission as determined by NASA, and we are preparing the spacecraft for a safe and successful uncrewed return,” Boeing said.
After Starliner’s return, NASA and Boeing will assess how successful the current test mission was, and how the thruster problems and other issues will be addressed. Among the questions to be answered: Will Starliner need to be redesigned? Will yet another test mission need to be flown?
Nelson said safety considerations would guide NASA’s decisions about Starliner’s future. He said he’s seen “some speculation in the press” that NASA may have settled on the course it did because of factors relating to the upcoming presidential election (for example, Vice President Kamala Harris’ status as chair of the National Space Council). But Nelson emphasized that politics “absolutely has nothing to do with it, and as long as I’m around here, it’s not going to.”
He also said he was 100% certain that Starliner’s problems will be resolved and that it will eventually fly NASA astronauts on a regular basis. When asked why, Nelson cited “the extensive cooperative working relationship between NASA and Boeing” as well as “Boeing’s willingness to carry through on this program.”
Update: Members of Congress were generally supportive of NASA’s decision but wanted to learn more about the process behind the commercial crew program. Here’s a statement from U.S. Sen. Maria Cantwell, D-Wash., chair of the Senate Committee on Commerce, Science and Transportation:
“Continuing American leadership in space is so important for our national security and scientific information. I spoke with Administrator Nelson this morning about the Starliner decision and asked NASA to regularly update the committee as they continue to work to bring our astronauts home safely.”
