Nasa decided that it would not take even a small risk in bringing back Butch and Suni on Starliner, when they had the option of returning them on SpaceX's Dragon capsule. Nasa decided the best option was to do this during a scheduled crew rotation, even though it would mean keeping the astronauts on the space station for several months.

A SpaceX capsule carrying a fresh crew to the space station launched Friday, setting the stage for the Starliner astronauts to finally come home.