(NewsNation) — NASA and SpaceX’s mission to relieve Starliner astronauts Butch Wilmore and Suni Williams, who have been in orbit for nine months,has officially launched.

A Falcon 9 rocket carrying Crew-10 is expected to dock at the International Space Station on Saturday at 11:30 p.m.

Once on board the ISS, there will be a handover period, which has been shortened due to concerns about commodities on the ISS after an upcoming supply mission experienced an issue.

The Crew-9 will then return, along with Wilmore and Williams. They’re expected to depart the ISS no earlier than March 19, pending weather at the splashdown locations off the coast of Florida, NASA said.

SpaceX fixes launch pad hydraulics issue

NASA astronaut Anne McClain is leading the Crew-10 mission, accompanied by NASA astronaut Nichole Ayers, JAXA astronaut Takuya Onishi and Roscosmos cosmonaut Kirill Peskov.

The mission was originally set to blast off Wednesday night, but the launch was canceled because of a “hydraulic ground issue with a ground support clamp arm for the Falcon 9 rocket,” NASA said.

NASA has reported SpaceX successfully flushed a suspected pocket of trapped air in the system.

The mission was originally scheduled for a Crew Dragon spacecraft, but due to delays, NASA instead opted for the Dragon Endurance.

Starliner astronauts stuck in space for 9 months

Wilmore and Williams blasted off on Boeing’s Starliner last summer for a mission initially meant to last two weeks. However, after multiple issues, including helium leaks in the service module and docking issues, NASA deemed it unsafe for them to return.

The two have pushed back against claims that they are “stranded” in space and have said they are thrilled to spend more time in orbit.

The Starliner returned to Earth safely in an autonomous flight, but it’s unclear if NASA will move forward with plans to use the spacecraft for future crewed missions.