Astronauts launching to space will finally relieve the pair who flew on Boeing's troubled capsule

Four astronauts are gearing up to launch to the International Space Station on Wednesday. Their arrival will, at long last, kick off the process of bringing NASA astronauts Suni Williams and Butch Wilmore home to Earth.

Williams and Wilmore have been the focus of public attention since they launched on the first crewed test flight of Boeing’s Starliner spacecraft in June. Although the plan called for them to stay on the space station for roughly a week, they have now spent nine months in orbit.

The Boeing capsule on which the pair launched encountered several problems on its journey to the ISS, including thruster malfunctions and leaking propulsion. So NASA opted to bring the Starliner craft back to Earth with no one onboard, leaving the two astronauts at the orbiting outpost.

NASA then switched crew rotations around to free up seats on a SpaceX Dragon capsule to enable Williams and Wilmore to return home.

That capsule arrived at the space station on Sept. 29, carrying NASA astronaut Nick Hague and Roscosmos cosmonaut Aleksandr Gorbunov. The plan calls for Wilmore and Williams to hitch a ride with them at the end of their roughly six-month mission.

That time is approaching as the new crew prepares to launch. Heading to space Wednesday are NASA astronauts Anne McClain and Nichole Ayers, Japanese astronaut Takuya Onishi and Russian cosmonaut Kirill Peskov. They are expected to ride into orbit aboard a SpaceX Falcon 9 rocket on a mission known as Crew-10.

Liftoff is scheduled for at 7:48 p.m. ET from NASA’s Kennedy Space Center in Florida.

The Crew-10 astronauts are set to arrive at the space station Thursday, docking at around 6 a.m. ET. From there, they’ll take over from the four who are wrapping up.

Although NASA’s plan for Williams and Wilmore’s return has remained relatively consistent since it was announced in August, SpaceX CEO Elon Musk and President Donald Trump recently made unsubstantiated claims that the Biden administration held up the flight back to Earth for political reasons.

The comments, which Musk made in a joint interview with Trump that aired on Fox News last month, led to a public spat on X between Musk and several current and retired astronauts. European astronaut Andreas Mogensen called Musk’s comments a “lie,” and Musk fired back, calling Mogensen an “idiot” and a derogatory term. Retired astronauts Scott Kelly, Mark Kelly and Chris Hadfield also weighed in online.

NASA has maintained that its decision about the timing of Williams and Wilmore’s return was based on the safety of the crew members and the space station. The agency in December delayed the Crew-10 launch until late March to allow more time to process a new Dragon capsule, but NASA and SpaceX ultimately decided to use a spacecraft that had previously flown to cut down on the wait. (SpaceX’s Dragon capsules are reusable.)

An exact date for Williams and Wilmore’s return to Earth hasn’t yet been announced. The handover period on the ISS typically lasts several days, during which outgoing crew members train and brief their incoming colleagues on experiments and other ongoing work.

NASA and SpaceX will also monitor conditions at the targeted splashdown sites off Florida before they announce an official landing date and time.

This article was originally published on NBCNews.com