Peggy Whitson, America’s most experienced astronaut, is leading an international crew of first-time fliers from India, Poland and Hungary on a privately-financed flight to the International Space Station — the fourth non-government mission mounted by Houston-based Axiom Space.
Strapped into a new, as-yet-unnamed SpaceX Crew Dragon capsule making its maiden flight, the crew blasted off from pad 39A at the Kennedy Space Center at 2:31 a.m. EDT Wednesday, roughly the moment Earth’s rotation carries the rocket into the plane of the space station’s orbit — a requirement for rendezvous missions.
Whitson’s crewmates are test pilot Shubhanshu Shukla of India, European Space Agency astronaut Sławosz Uznański-Wiśniewski of Poland, and Hungarian engineer Tibor Kapu. All three are making their first space flight.
SpaceX 
The Crew Dragon spacecraft, serial number C213, is the fifth and final addition to SpaceX’s fleet of astronaut ferry ships built for NASA flights to the space station and for privately-funded commercial missions to low-Earth orbit.
The Falcon 9 first stage booster, B1094, is making its second flight. After propelling the Crew Dragon out of the lower atmosphere, the first stage will attempt a return-to-launch-site landing at the Cape Canaveral Space Force Station. To date, SpaceX has pulled off 466 successful first stage landings, 63 of them in Florida.
GIORGIO VIERA/AFP via Getty Images 
Launch originally was planned for June 11, but the flight was held up by work to resolve an oxygen leak in the Falcon 9’s first stage plumbing. It then was delayed by renewed concern about small-but-persistent air leaks in a Russian compartment aboard the space station that connects the lab’s aft docking port to the Zvezda service module.
The leakage in the PrK vestibule was first noticed in 2019 and has been closely monitored ever since. The compartment is closed off unless a Russian spacecraft is using that docking port.
NASA has not explained what led to the latest concern, or what was done to resolve it. But sources said the Russians agreed to lower air pressure in the PrK compartment more that usual, ensuring the higher sea-level pressure in Zvezda and the rest of the station results in a tighter-than-usual seal between the service module’s aft hatch and the leaky PrK.
That minimizes, if not eliminates, any chance the air supply in the station’s other modules could be affected if the leak suddenly worsened.
Plans for the Ax-4 mission
Assuming an on-time liftoff, Whitson, Shukla, Uznański and Kapu will dock at the space-facing port of the station’s forward Harmony module at 7 a.m. Thursday.
They’ll be welcomed aboard by NASA Crew 10 commander Anne McClain, pilot Nicole Ayers, Russian cosmonaut Kirill Peskov and Japanese flier Takuya Onishi, along with Soyuz MS-27 crewmates Sergey Ryzhikov, Alexey Zubritsky and NASA’s Jonny Kim.
Whitson, who holds a doctorate in biochemistry, retired from NASA in 2018 and now works for Axiom. She ranks ninth in the world for time in space, No. 1 in the world among female astronauts and No. 1 overall among U.S. astronauts.
NASA 
Going into the Ax-4 flight, Whitson had logged 675 days in space across three NASA flights and one post-retirement mission for Axiom Space.
As if all that’s not enough, she’s also the world’s most experienced female spacewalker — seventh in the world overall — with 10 excursions totaling 60 hours and 21 minutes. She was the first female and non-military chief of NASA’s astronaut office and served as the first female commander of the International Space Station.
“I think I’m somewhat addicted to space,” she said in an interview with CBS News. “I really like being there, and it’s just exhilarating living in an environment so different than what we have here on Earth. And having adapted to that environment, it is fun for me to share my experience with the rookie flyers that are going with me.
“I get to share in their experience of the first time, all over again,” she added.
Uznański-Wiśniewski summed up the feelings of his Ax-4 crewmates, saying “we consider ourselves extremely lucky to be flying with Peggy, the best commander we could have wished for.”
The Ax-4 mission follows in the footsteps of Axiom’s first three “private astronaut missions,” or PAMs, a formal designation by NASA for commercial research flights to the International Space Station.
Throughout the two-week mission, Whitson and her crewmates will carry out a full slate of science research and technology demonstrations, along with interactive educational events in the crew’s home countries. They were trained for space station operations and will have full use of the U.S. segment of the orbital lab.
“We’ve got a lot of objectives for our mission,” Whitson said. “The first, obviously, is realizing the return of these three countries to space, but this will be their first time to go to the International Space Station.
“Obviously, they will have a number of different scientific, technological and educational goals as part of their missions from each of the countries, from India, Poland and Hungary. I will be conducting some research for Axiom space as well.”
All told, researchers from 31 countries will be helping evaluate data from the Ax-4 experiments and technology demonstrations. Whitson said the mission “opens up access to countries that might not normally get access to space. So this is very exciting.”
