WASHINGTON (Reuters) – NASA said on Wednesday that astronauts delivered to the International Space Station by Boeing (NYSE:)’s Starliner could return on SpaceX’s Crew Dragon in February 2025 if Starliner is still deemed unsafe to return to Earth.

Starliner spacecraft launched in June carrying two astronauts to the ISS in a high-stakes test mission required before NASA can certify the spacecraft for routine astronaut flights.

But the mission, initially expected to last about eight days, has been drawn out far longer by an array of problems with the craft’s propulsion system that Boeing and NASA have been scrambling to fix.

Those problems have called into question Starliner’s ability to safely return to Earth its crew, veteran NASA astronauts Butch Wilmore and Suni Williams. NASA has been examining whether a Crew Dragon capsule will have to bring them home instead.