Boeing’s Starliner mission returns to Earth empty.

After months of data analysis and internal deliberation, NASA announced today that Starliner will return to Earth in September, sans crew. Meanwhile, astronauts Butch Wilmore and Sunita Williams will remain aboard the International Space Station until February 2025, when they return aboard SpaceX’s Dragon spacecraft as part of the Crew-9 mission.

NASA noted that while the astronauts’ eight-month stay on the ISS will be longer than expected, others have stayed on the ISS for as long as 12 months. While there, Wilmore and Williams will be involved in research, station maintenance and possibly a few spacewalks.

Boeing launched the first crewed Starliner mission — a test mission — on June 5, with problems beginning about 24 hours later. During the final phase of its approach to the ISS, five of Starliner’s 28 thrusters went offline and several helium leaks developed in the spacecraft’s propulsion system. Since then, NASA and Boeing engineers have been conducting a root cause analysis, testing the spacecraft’s thrusters and testing a replica engine here on Earth.

NASA bet big on Starliner — about $4.2 billion, according to a contract awarded to Boeing in 2014 to develop Starliner. Boeing has also staked its stakes high, with cost overruns for the capsule totaling more than $1.5 billion.

NASA’s goal was to have two commercial crew carriers, and so contracts were awarded to Boeing and SpaceX. But while SpaceX completed its certification mission in 2020 and has since flown eight NASA missions, Boeing’s Starliner has faced numerous delays.

While the incident may seem like the nail in the coffin for Starliner, NASA leaders said at today’s news conference that they are working closely with Boeing. They pushed back against a question that implied there was any loss of confidence in the company or Starliner. Instead, they suggested there was merely a “disagreement” about the level of risk.

“Space flight is risky, even in the safest and most routine ways,” said NASA Administrator Bill Nelson. “A test flight is by its very nature neither safe nor routine. The decision to keep Butch and Suni aboard the International Space Station and to bring Boeing’s Starliner home unmanned is a result of our commitment to safety: our core value and our North Star.”

Nelson later said he is “100 percent” confident that Starliner can carry out a crewed mission to the ISS in the future.