KENNEDY SPACE CENTER —SpaceX said it was standing down from the Wednesday morning launch of the crewed Ax-4 mission to repair a liquid oxygen leak that was discovered during inspections.

In a statement Tuesday night, SpaceX said it was standing down to "allow additional time for SpaceX teams to repair the LOx leak identified during post static fire booster inspections."

The company added a new launch date will be shared once the repair is complete and "pending range availability."

The mission will see SpaceX’s Falcon 9 rocket and its crewed Dragon send up the Axiom Mission 4 (Ax-4) from Kennedy Space Center’s Launch Complex 39A, according to SpaceX.

The scrub of Wednesday's launch was the second time the Ax-4 mission has been pushed, as high winds forced an initial Tuesday morning slot to be called off.

Starting a new trek

The Dragon spacecraft that will carry the four astronauts is brand new and this will be its maiden voyage. Its name is C213.

This is the last Crew Dragon capsule that SpaceX will build, as the company’s business model is to reuse its rockets and spacecraft.

SpaceX has five Dragon capsules.

The first-stage Falcon 9 booster for this mission is named B1094. Before this launch, it has only had one other: The Starlink 12-10 mission.  

The Falcon 9 is expected to land at Landing Zone 1, so a sonic boom is expected to be heard.

The Dragon capsule will dock with the ISS for up to 14 days.

About the Ax-4 mission

This will be the fourth time the Texas-based Axiom Space has used SpaceX to send astronauts to the ISS.

This will be another all-private human crewed mission from Axiom Space, where the four will stay on the floating laboratory for up to 14 days.

And the quartet will be busy for those two weeks as they bring more than 60 experiments with them.

Some of these experiments are in partnerships with private companies and space programs that include 31 countries.

Some of these research studies include:

• “How to support astronauts with insulin-dependent diabetes during short-duration missions in microgravity”
  
  
• “Examining microgravity's impact on the brain and cognitive risks”
  
  
• “Investigating the impacts of spaceflight on germination and growth of crop seeds”
  
  
• “Studying astronauts' mental and behavioral health on the International Space "Station”
  
  
• “Testing methods to extend pharmaceutical shelf-life in space”
  
  
• “Examining how space conditions affect human bacterial, viral, and fungal microbiomes”
  
  
• “Studying upper atmospheric thunderstorms”

Go here to learn more about the research being conducted during the Ax-4 mission.

Mission specialist Tibor Kapu, left, pilot Shubhanshu Shukla, Cmdr. Peggy Whitson, and mission specialist Sławosz Uznański-Wiśniewski will be heading to the International Space Station for two weeks to conduct more than 60 experiments. (Axiom Space)

Meet the Ax-4 crew

The four astronauts — three of whom will venture into the deep black for the first time — have a diverse background.

“The Ax-4 crew includes members from India, Poland, and Hungary, marking each nation’s first mission to the space station in history and second government-sponsored human spaceflight mission in over 40 years,” explained Axiom Space.

Cmdr. Peggy Whitson: The former NASA astronaut became the first woman to command a private space assignment during the Ax-2 mission in 2023. She was recently inducted into the 2025 U.S. Astronaut Hall of Fame.

Adding up her mission time in her career, Whitson has spent 675 days, four hours and five minutes in space. She is a real space veteran while her three crew members will be first timers for this mission.

Pilot Shubhanshu Shukla: A pilot for the Indian Air Force, he will be the second Indian Space Research Organization astronaut to go into space since 1984.

Mission specialist Sławosz Uznański-Wiśniewski: As a member of the European Space Agency, he is both a scientist and engineer. He will be the second Polish astronaut to go into space since 1978.

Mission specialist Tibor Kapu: He has studied mechanical engineering with a master’s degree specializing in polymer technology. He has dabbled in pharmaceutical industries and worked on the development of a hybrid car battery. He will be the second Hungarian astronaut since 1980 to go into space.