NASA and SpaceX launched a long-awaited crew to the International Space Station (ISS) on Friday, paving the way for the return of U.S. astronauts Butch Wilmore and Suni Williams, who have been stranded on the orbital lab for nine months.

SpaceX's Falcon 9 rocket lifted off at 7:03 p.m. from NASA's Kennedy Space Center in Florida, carrying four astronauts who will replace Wilmore and Williams. Both are veteran NASA astronauts and retired U.S. Navy test pilots who became the first to fly Boeing's Starliner capsule to the ISS in June.

However, problems with Starliner's propulsion system during the flight led to an extension of their planned eight-day stay, as NASA deemed it too risky for them to return on the craft. Starliner ultimately returned to Earth empty in September.

While Friday's Crew-10 mission is a routine crew rotation flight, it also marks a crucial step in bringing Wilmore and Williams back to Earth. They are scheduled to depart the station on March 19 after the Crew-10 astronauts arrive Saturday night.