NASA astronauts Zena Cardman and Stephanie Wilson were expected to launch on SpaceX's Crew-9 mission on Sept. 28. Still on Earth, they spoke about how they're feeling.

Because NASA rotates space station crews approximately every six months, this newly launched flight with two empty seats reserved for Wilmore and Williams won’t return until late February. Officials said there wasn’t a way to bring them back earlier on SpaceX without interrupting other scheduled missions.

Two astronauts — one American, one Russian — are headed to the International Space Station with two empty seats for crewmates who are already in orbit.