NASA astronauts Sunita Williams and Barry Wilmore, who flew to the International Space Station (ISS) in June this year on board Boeing’s faulty Starliner capsule, will return to Earth early next year, the space agency said in a release on Saturday.

NASA will return the Boeing’s Starliner to Earth without the two astronauts aboard the spacecraft, the agency said.

The uncrewed return will allow NASA and Boeing to continue gathering testing data on Starliner during its upcoming flight home, while also not accepting more risk than necessary for its crew.

In a post on X, NASA said: “After extensive review by experts across the agency, NASA’s @BoeingSpace Crew Flight Test will return with an uncrewed #Starliner. Astronauts Butch Wilmore and Suni Williams are scheduled to return to Earth next spring.”

Wilmore and Williams, who flew to the International Space Station in June, have been busy supporting station research, maintenance, and Starliner system testing and data analysis, among other activities, the NASA release said.

“Spaceflight is risky, even at its safest and most routine. A test flight, by nature, is neither safe, nor routine. The decision to keep Butch and Suni aboard the International Space Station and bring Boeing’s Starliner home uncrewed is the result of our commitment to safety: Our core value and our North Star,” said NASA Administrator Bill Nelson, adding: “I’m grateful to both the NASA and Boeing teams for all their incredible and detailed work.”

Wilmore and Williams will continue their work formally as part of the Expedition 71/72 crew through February 2025. They will fly home aboard a Dragon spacecraft with two other crew members assigned to the agency’s SpaceX Crew-9 mission. Starliner is expected to depart from the space station and make a safe, controlled autonomous re-entry and landing in early September, NASA said in the release.

NASA and Boeing identified helium leaks and experienced issues with the spacecraft reaction control thrusters on June 6 as Starliner approached the space station.

Since then, engineering teams have completed a significant amount of work, including reviewing a collection of data, conducting flight and ground testing, hosting independent reviews with agency propulsion experts, and developing various return contingency plans.

The uncertainty and lack of expert concurrence does not meet the agency’s safety and performance requirements for human spaceflight, thus prompting NASA leadership to move the astronauts to the Crew-9 mission, the space agency said.