Boeing’s inaugural astronaut mission concluded on Friday night with an empty capsule landing. Two test pilots, Butch Wilmore and Suni Williams, remain in space. NASA deemed their return too risky and scheduled them for a SpaceX flight instead.

The Starliner capsule, after a six-hour descent from the International Space Station, landed on autopilot in New Mexico’s White Sands Missile Range. The mission, initially delayed by thruster failures and helium leaks, became a drawn-out saga as engineers worked to understand the capsule’s issues.

Boeing insisted that Starliner was safe to bring Wilmore and Williams home, but NASA disagreed. The astronauts are now scheduled to return on a SpaceX flight at the end of September, meaning they will stay in space until February, over eight months after their initial launch.

Their return on Starliner, initially planned for mid-June, was canceled due to the thruster problems and helium loss, which NASA deemed too risky for a return trip. The empty capsule, equipped with fresh software updates, left the space station carrying old station equipment.

“She’s on her way home,” Williams communicated as the capsule undocked from the space station and disappeared into the darkness. Williams stayed awake to monitor the landing, reporting a “good landing, pretty awesome” to Boeing Mission Control.

Cameras on the space station and NASA planes captured the capsule as it reentered the atmosphere. The touchdown was met with cheers. Despite some snags during reentry, including further thruster issues, Starliner made a “bull’s-eye landing,” according to Steve Stich, NASA’s commercial crew program manager.

Stich, acknowledging the successful landing, expressed regret that Wilmore and Williams were not on board. Boeing, although not present at the Houston news briefing, issued a statement supporting NASA’s decision in a note to employees. The company expressed pride in the team and the spacecraft’s performance.

Starliner’s crew demonstration marked the culmination of a challenging journey riddled with delays and setbacks. After the retirement of the space shuttles, NASA hired Boeing and SpaceX for orbital taxi services. Boeing’s initial test flight in 2019, without a crew, was plagued by problems, necessitating a repeat in 2022, which unearthed further flaws and cost over $1 billion in repairs.

SpaceX’s upcoming crew ferry flight, their tenth for NASA since 2020, is scheduled to launch later this month. The Dragon capsule will embark on a six-month expedition with only two astronauts, as two seats are reserved for Wilmore and Williams on the return journey.

Wilmore and Williams, experienced astronauts and retired Navy captains, were aware of potential obstacles during the test flight. They have been actively involved in repairs and experiments aboard the space station and are now considered full-time crew members.

Even before launch, Starliner’s propulsion system was experiencing a helium leak, which was deemed minor and contained. However, four additional leaks emerged after liftoff, followed by five thruster failures. Although four thrusters were restored, the malfunctions raised concerns about the capsule’s descent from orbit.

Boeing conducted extensive thruster tests in space and on Earth, concluding that the spacecraft could safely return the astronauts. However, NASA remained hesitant about the thruster situation and opted for SpaceX.

Following undocking, flight controllers conducted further test firings of the capsule’s thrusters, one of which failed to ignite. Engineers suspect that repeated firing causes the thrusters to overheat, causing protective seals to swell and impede propellant flow. The section containing the thrusters was discarded before reentry, preventing examination of the parts.

Starliner will be transported to NASA’s Kennedy Space Center within a few weeks for further analysis.

NASA officials emphasized their commitment to having two competing U.S. companies transport astronauts. SpaceX and Boeing are expected to alternate launches, once a year each, until the space station is decommissioned in 2030. The limited timeframe for Boeing to catch up with SpaceX is acknowledged, but NASA confirmed their intention to support Starliner’s progress.

Stich stated that it is too early to determine the timing of the next Starliner flight with astronauts. “It will take a little time to determine the path forward,” he said.