NASA and SpaceX are hopeful for a Friday launch of a much-anticipated crewed mission to bring home US astronauts Butch Wilmore and Suni Williams, who have been stranded on the International Space Station (ISS) for nine months.
SpaceX and NASA had initially planned to launch the Crew-10 mission, a replacement crew of four astronauts from Florida, on Wednesday. However, a last-minute issue with the rocket’s ground systems caused a delay.
On Thursday, NASA confirmed that SpaceX had resolved the problem by clearing a suspected air pocket from a hydraulic clamp arm and reported that the weather had a 95% chance of being favorable for a Friday launch.
Scheduled for liftoff at 7:03 pm ET (2330 GMT), Crew-10 is expected to reach the ISS on Saturday night.
Wilmore and Williams, both veteran NASA astronauts and US Navy test pilots, were the first to test-fly Boeing’s Starliner spacecraft to the ISS. However, due to problems with Starliner’s propulsion system, their planned eight-day stay was extended, as NASA deemed it too risky for them to return home on the craft, which later returned to Earth empty.
The mission has become politically charged, with President Donald Trump and SpaceX CEO Elon Musk suggesting, without evidence, that former President Joe Biden kept the astronauts on the station for political reasons.
“We came prepared to stay long, even though we planned to stay short,” Wilmore said, adding that he didn’t believe NASA’s decision to keep them on the ISS until Crew-10’s arrival had been politically motivated. “That’s what your nation’s human spaceflight program is all about,” he said, referring to the need for planning for unexpected contingencies.
NASA has said that Wilmore and Williams were required to remain on the ISS to maintain the station’s minimum staffing levels. Despite the extended stay, the astronauts have been conducting scientific research and routine maintenance with other crew members.
The demand for an earlier return from Trump and Musk led NASA to move the Crew-10 mission launch date up from March 26, swapping in a SpaceX capsule that was ready sooner.
The pressure from Musk and Trump has had an unusual impact on NASA’s preparation and safety processes, which typically follow a well-defined procedure. SpaceX’s “rapid pace of operations” required NASA to alter some of its flight safety verification processes. NASA also had to address “late-breaking” issues, including a fuel leak on a recent Falcon 9 launch and concerns about the deterioration of a coating on the Dragon capsule’s thrusters.
NASA space operations chief Ken Bowersox noted, “We’re not quite as agile as they are, but we’re working well together.”
Once Crew-10 arrives, Wilmore, Williams, and two other astronauts—NASA’s Nick Hague and Russian cosmonaut Aleksandr Gorbunov—will return to Earth in a capsule that has been docked to the ISS since September as part of Crew-9’s mission.
If Crew-10 launches as scheduled, it will dock with the ISS at 11:30 pm ET Saturday (0330 GMT Sunday), followed by a handover ceremony allowing the Crew-9 team to depart on March 19.
