The crew set to relieve NASA's stranded astronauts were all smiles as they completed a dry-run for Wednesday's launch.
Sunita Williams and Butch Wilmore have spent nine months in space, waiting for their replacements before they can head back to Earth.
Now, SpaceX Crew-10 is one step closer to making that happen.
Japan's Takuya Onishi, Russia's Kirill Peskov, and NASA's Anne McClain and Nichole Ayers are scheduled to launch at 7:48pm ET tomorrow from NASA's Kennedy Space Center in Florida.
If the launch goes according to plan, the capsule should dock to the ISS at roughly 10am ET on Thursday, allowing Williams and Wilmore to depart March 16.
On Sunday, Crew-10 spent the day 'donning spacesuits and completing air leak checks,' according to a NASA statement.
Once they suited up, the astronauts climbed aboard the SpaceX Dragon capsule that will bring them to the International Space Station (ISS) for a test run. By the time Williams and Wilmore get home, they will have spent 284 days in space.
Their mission could stretch even longer if the Crew-10 mission is delayed. But if Sunday's dry-run is any indication, the launch should go off without a hitch.
'We are going to take a little bit of an adventure,' McClain, who is a U.S. Army colonel and OH-58D Kiowa Warrior helicopter pilot, told Florida Today
'We're ready to high-five them, bring them home.'
After the crew members left the launch pad, SpaceX conducted tests of the Falcon 9 rocket that will be used to launch the Dragon spacecraft.
Once Crew-10 boards the ISS, they will live on the space station for six months, carrying on the work that the Starliner and Crew-9 astronauts were conducting before they arrived.
The capsule set to take Williams and Wilmore home is already docked at the ISS.
Also joining the stranded astronauts on the return mission will be NASA's Nick Hague and Russia's Aleksandr Gorbunov, who arrived at the ISS in September 2024.
McClain, the mission's commander, said Friday that she and her fellow Crew-10 mates have been in constant contact with all four on the orbiting laboratory.
Program Manager Steve Stich said Crew-10 backup launch opportunities are available at 7:25pm Thursday and 7:04pm Friday.
While the capsule has been docked on the ISS for months, the crew had to wait for Crew-10's arrival before they can return to Earth.
That's because NASA protocol calls for a 'handover period' when transitioning between ISS crews.
This is a few days of overlap between the incoming astronauts and the outgoing ones allows the departing crew to get the new astronauts up to speed on space station operations and ensures a smooth transition between ISS teams.
The handover period usually lasts five days, but this time, NASA shortened it to just two days to conserve food on the ISS and open up more undocking opportunities for the Crew-9 spacecraft in case the weather interferes with its March 16 return.
When the pair launched aboard Boeing's Starliner spacecraft on June 5, they were only supposed to spend eight days on the ISS.
But a series of technical issues with Starliner, including thruster failures and helium leaks, ultimately drove NASA to send the faulty spacecraft home without its crew in September.
The crew's delayed return recently entered the political spotlight after SpaceX Chief Executive Elon Musk and President Donald Trump claimed the astronauts were 'abandoned' in space by the Biden administration for 'political reasons.'
Musk has said that the former president rejected his offer to bring the Starliner crew home earlier because it would have made Donald Trump 'look good.'
Musk backed Trump during the 2024 presidential race, donating $288 million to his campaign and appearing at several MAGA rallies.
During a recent appearance on Joe Rogan's podcast, the Joe Rogan Experience, Musk claimed the Biden administration rejected his offer to bring the Starliner astronauts home sooner to avoid making Trump 'look good.'
He explained that the former administration did not want to jeopardize Kamala Harris' presidential campaign and intentionally 'pushed the return date past the inauguration date.'
