CAPE CANAVERAL, Fla. — A SpaceX crew capsule successfully docked with the International Space Station (ISS) on Sunday, just over a day after its launch. This mission was significant as it brought essential replacements for two astronauts who had become stranded aboard the ISS.

The arriving crew consisted of four astronauts representing the United States, Japan, and Russia. They will spend the next few days familiarizing themselves with the ISS and its operational procedures, guided by the two stranded astronauts—Butch Wilmore and Suni Williams. Following this transition period, Wilmore and Williams are scheduled to return to Earth later in the week using a SpaceX capsule that has been in orbit since last year. Their unanticipated extended mission began back in June, and they had originally anticipated only a week’s stay.

Wilmore and Williams were aboard Boeing’s first astronaut flight, which was meant to bring them to the ISS. However, due to multiple issues encountered by the Boeing Starliner capsule, NASA decided that the capsule should return to Earth empty, necessitating the astronauts to await a SpaceX crewed flight for their return.

The duo was initially slated to be retrieved in late September aboard a capsule with a smaller crew of two, plus two vacant seats for their return journey. However, further delays arose when the new capsule intended for their replacements required extensive battery repairs, forcing the use of an older capsule instead. This change has pushed their return timeline forward, now expected to occur around mid-March, weather permitting.

As for their imminent return, the SpaceX capsule carrying Wilmore, Williams, and the two incoming astronauts is planned to undock from the ISS as early as Wednesday. They are set to splash down off the coast of Florida, marking the culmination of their extended stay aboard the ISS.

This mission not only highlights the ongoing partnership between NASA and commercial space entities like SpaceX and Boeing, but it also underscores the complexities and challenges of maintaining continuous crewed presence aboard the ISS. As the space community continues to innovate and iterate on its missions, the collaboration across international lines remains crucial for future explorations.