While Suni Williams and Butch Wilmore’s situation is unusual, their return trip will be pretty routine, as they were already slated to fly home on a SpaceX capsule as part of a scheduled crew rotation.

Two NASA astronauts flew to the International Space Station in June on Boeing's Starliner capsule. The test flight was planned for eight days but technical troubles forced the capsule to return empty.

SpaceX founder Elon Musk said President Trump has asked the company to bring home the two NASA astronauts from Boeing’s Starliner mission on board the ISS “as soon as possible.”