Suni Williams and Butch Wilmore have been on the International Space Station for 15 weeks. They were only supposed to be there for eight days.

Two astronauts relinquished their seats on a four-person spacecraft so that their colleagues could return to Earth from the ISS, where they’ve been stuck since June.

SpaceX successfully completed the first step on Sunday to rescue two astronauts stranded on the International Space Station, but it won’t bring the pair home for another five months.