Boeing's Starliner Crew Mission Returns to Earth, But Its Astronauts Are Still in Space

Starliner spacecraft returns safely to Earth without astronauts

TO Lee Billings

After three harrowing months in space, the orbital mission, which was originally scheduled to last just over a week, ended with an autonomous landing using a parachute system and airbags shortly after midnight ET at NASA's White Sands Space Harbor in New Mexico.

Starliner is a Boeing spacecraft that has begun a troubled test flight to the International Space Station (ISS) in June— has finally returned to Earth. However, the same cannot be said for its crew: NASA astronauts Butch Wilmore and Suni Williams stay on board the ISSLast month, space agency officials, citing safety concerns, decided instead send them home in February 2025 by using the time-tested Dragon spacecraft built and operated by Boeing's aerospace rival, SpaceX. Adapting to the changes required two other NASA astronauts, Zena Cardman and Stephanie Wilson, to be dropped from SpaceX's next scheduled Dragon flight to the ISS: the Crew 9 mission, scheduled to launch later this month. That leaves two open seats for Wilmore and Williams when Dragon returns to Earth next February.

“It was a great day to return Starliner, and it was great to successfully undocking, deorbiting, and landing the vehicle,” said Steve Stich, manager of NASA’s Commercial Crew Program, during a post-landing press conference in which he summed up the spacecraft’s “nearly flawless” performance. “I’m thrilled for our Boeing team and all of our colleagues who worked on this mission across the country on the NASA team and the Boeing team… It’s a testament to those folks that we got the vehicle back today.”

Chasing the Dragon

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The successful landing — the third for Starliner — means Boeing’s program has survived and will fly another day. But much of what happens next is still up in the air.

The test flight was supposed to be the final step in certifying Starliner’s readiness to fly astronauts to the ISS every year. But the spacecraft’s failure to return with a crew could prompt NASA to require additional test flights before issuing that certification — at Boeing’s expense. When the space agency selected Boeing and SpaceX to develop the crewed spacecraft in 2014, the two companies signed “fixed-price” contracts in which they, not NASA, would cover cost overruns. In addition, NASA’s payments would be contingent on each company achieving certain set milestones. The space agency awarded a total of $2.6 billion to SpaceX and $4.2 billion to Boeing. SpaceX has flown the first manned Dragon to the ISS in May 2020 and has been fulfilling its contractual obligations to NASA ever since. In contrast, technical errors and delays interfered with the Boeing Starliner program, and quarterly reports Since late June, it has become known that the company has lost $1.6 billion so far due to these efforts.

At a press conference last month announcing the transition to Dragon as Wilmore and Williams’ return vehicle, NASA Administrator Bill Nelson expressed “100 percent” confidence that Starliner would carry crews again, and noted that he had recently spoken with Boeing’s new CEO, Kelly Ortberg. “He expressed to me his intent that they would continue to work on the issues once Starliner had returned safely,” Nelson said.

It’s still unclear how and when Starliner will return to crewed flights, or what guarantees other spacefaring nations that partner with NASA on the ISS might require before sending crews on Boeing’s spacecraft. But one thing is for sure: The company is running out of time to meet its commitments to NASA. The space agency aims to deorbit the ISS in 2031, and recently announced The company hired SpaceX to carry out the task, using a heavily modified Dragon.

A long farewell

At 1:29 a.m. ET Thursday, Wilmore and Williams closed the Starliner's hatch to prepare for the unmanned launch. The vehicle, nicknamed Calypso— undocked from the ISS at 6:04 p.m. ET Friday, leaving the astronauts behind as the ISS flew over central China. Moments after undocking, the spacecraft performed an “escape burn,” a dozen sequences of pulses from its auxiliary thrusters to maneuver up and away from the ISS to avoid a collision with the orbiting habitat. Calypso Shrinking to a speck barely visible through the ISS windows, Williams radioed flight controllers with a simple, almost mournful statement: “She's on her way home.”

Over the next few hours, the spacecraft underwent a series of diagnostic tests as it drifted 90 kilometers from the ISS. Then, at 11:17 p.m. EST Calypso began its “de-orbit” descent, using its auxiliary thrusters to orient itself while its more powerful main engines fired to send it plummeting through our planet's atmosphere. During this descent, another burst of auxiliary thruster firing ensured that CalypsoThe empty crew compartment of the ship separated from the service module, which burned up at high altitude, as planned.

The fiery end of the service module, which was needed to expose the protective heat shield to bring Starliner home, was the main stumbling block in fixing the spacecraft’s most troubling problems. The expendable module contains 28 auxiliary thrusters, five of which failed during Starliner’s rendezvous with the ISS on June 6. It’s also the site where Starliner repeatedly sprang several small leaks of helium, the inert gas used to push fuel through the engines. But with the faulty hardware destined for a grand destruction rather than to be recovered and studied, the only option was to analyze it from afar, collecting as much data as possible in the hopes of finding causes — and fixes — before the service module burned up in Earth’s skies.

In the dog house

From these remote studies, as well as ground tests of identical engines, NASA and Boeing engineers traced the failure of five service module engines to overheating during firing. The service module’s auxiliary engines are mounted in four engine bays called “doghouses,” which the researchers determined retained more heat than expected when the engines fired, exacerbating the problem. The overheating likely caused Teflon seals to swell and restrict fuel flow, ultimately causing the failures. In a worst-case scenario, such failures could lead to disasters such as Starliner colliding with the ISS and being destroyed, or falling off and breaking up in a fireball upon reentry.

While engineers had found a likely cause for the engine problems, uncertainty remained. Four of the five failed Starliner engines, for example, were later recovered, but no one could fully explain how they happened. In discussions with NASA, Boeing officials nonetheless maintained that it was safe to send two astronauts home on the spacecraft—a key goal that, if not met, would likely require another, costly future crewed test flight. But without the ability to thoroughly test the engines in orbit to ensure they were working, NASA ultimately decided it was safer to send Starliner back without Wilmore and Williams.

During the last meeting on the issue, “there was some tension in the room,” Stich acknowledged at a press conference before Wednesday’s takeoff. “Boeing had confidence in the model they had created that tried to predict the degradation of the engines for the remainder of the flight… The NASA team looked at the model and saw some limitations, and it really came down to the question of, ‘How confident are we in the engines — and how much can we predict their degradation — from undocking to deorbit?’ And [we] “I couldn't come to terms with it.”

Despite this, Stich told a press conference on Wednesday that “we are confident in the car… We have had two good [uncrewed] There have been no landings with Starliner so far, and we expect another one on Friday.”

With this nearly flawless (but not quite triumphant) return and landing now on paper, everyone expects Boeing to redouble its efforts to recover from its spaceflight failures and restore Starliner’s tarnished reputation. Whether NASA—or anyone else—should still be expected to trust these efforts, however, is another matter entirely.