The astronauts lifted off aboard the Starliner on June 5. The setbacks started the next day.

As Starliner was approaching the International Space Station, five of the capsule’s 28 reaction control system thrusters malfunctioned, delaying the docking process by almost an hour.

Those thrusters are on the spacecraft’s service module and are used to move the capsule around in orbit, particularly to adjust its position as it docks and undocks with the space station.

Four thrusters were eventually restored, which allowed the astronauts to complete their arrival at the space station, but the problem prompted NASA to launch an investigation into what caused the thrusters to shut down.

Engineers with NASA and Boeing have been using a test…