The pair originally set out on an eight-day mission last June, but the Boeing Starliner had so many problems NASA deemed it unsafe to carry anyone back to Earth. Wilmore and Williams began what would ultimately be a more than nine-month stay aboard the ISS.

A launch pad problem has forced a flight delay to replace NASA's two stuck astronauts. The new crew needs to get to the International Space Station before Butch Wilmore and Suni Williams can head home after nine months in orbit.