They will return to Earth with SpaceX, NASA has decided.

The Starliner’s successive difficulties led to the difficult decision not to use the ship to return Butch Wilmore and Sonny Williams to Earth. It’s a snub to Boeing, which has already been hobbled by repeated setbacks with its aircraft.

Astronauts Butch Wilmore and Suni Williams will initially depart for an eight-day mission, eventually to nearly eight months on the International Space Station (ISS). They will be aboard a SpaceX mission that will return them to Earth in February. The space veterans knew this was the first crewed test flight of the spacecraft and that the mission “involved some risk,” he noted.

“Too dangerous”

For weeks, Boeing and NASA teams have been running tests to better understand the cause of the flight problems, particularly with the spacecraft’s thrusters. The main concern is that Starliner won’t be able to generate the thrust needed to de-orbit and begin its descent toward Earth.

“Attempting to return with these malfunctions was simply too risky for the crew,” said Steve Stich, a senior NASA official. Starliner will then depart the International Space Station and return to Earth, without its crew, “in early September.”