The SpaceX Dragon spacecraft carrying the Axiom Mission 4 (Ax-4) crew successfully launched at 2:31 a.m. EDT on June 25, 2025, from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. The mission, led by commercial space station developer Axiom Space in partnership with SpaceX and NASA, marks the company’s fourth private astronaut journey to the International Space Station (ISS).
The Dragon capsule successfully docked to the International Space Station at 6:31 a.m. EDT on Thursday, June 26, at the space-facing port of the Harmony module. NASA streamed the docking live on NASA+. The hatch between the SpaceX Dragon and the ISS opened at 8:14 a.m. EDT, and the Expedition 73 crew members welcomed the Ax-4 crew aboard the ISS.
Upon arrival at the ISS, Expedition 73 Commander Takuya Onishi greeted the crew, telling Ax-4 commander Peggy Whitson, “It’s a great honor and a privilege to have such a legendary astronaut like you on board with us.” He then turned to the three first-time visitors to the station, congratulating them on their journey and joking, “We’ve been waiting for you guys for so long,” referring to the mission’s multiple delays.
International crew, historic flight
Ax-4 carries a four-person crew led by Whitson, Axiom’s director of human spaceflight and former NASA astronaut. Whitson, who has spent more time in space than any American — 675 days and counting — previously commanded Axiom’s second mission to the ISS.
In a historic milestone, the crew includes members from India, Poland, and Hungary. Pilot Shubhanshu Shukla of India, Mission Specialist Sławosz Uznański-Wiśniewski of Poland, and Mission Specialist Tibor Kapu of Hungary are making their respective nations’ first visits to the ISS and second human spaceflights overall.
“This mission shows that space exploration is no longer limited to a few nations — it’s a shared effort that reflects the best of what we can achieve together,” said Whitson. “We launched a message to the world that science, exploration, and unity transcend borders.”
Launch delayed by weather and leaks
Ax-4 faced multiple delays over two weeks, starting with bad weather and a liquid oxygen leak on SpaceX’s Falcon 9, both of which were resolved before launch. These issues pushed the launch from its original target in early June.
Another delay came from an ongoing slow air leak in the ISS’s Zvezda module. Over the last five years, the leak has persisted at a steady rate, but on June 12, NASA cited concerns over a “new pressure signature” and paused the launch to assess repair work. The pressure appears to be holding steady, though teams are still monitoring it to see if any additional troubleshooting is needed. NASA gave no update on the leak when announcing the new launch date.
Ambitious research agenda
During their planned 14-day stay aboard the orbiting laboratory, the Ax-4 crew will conduct approximately 60 different research activities representing 31 nations — the most on an Axiom mission to date. The experiments will focus on human health both in space and on Earth, covering topics from cancer treatments to on-orbit farming to the effects of microgravity on the brain, heart, and muscles.
The mission is a collaborative effort involving the European Space Agency (ESA), the Indian Space Research Organization (ISRO), and the Hungarian to Orbit (HUNOR) program, all of which have contributed experiments to be conducted during the stay.
NASA, which Axiom will pay for crew training and access to facilities, will conduct a few of the planned activities, but the majority will be carried out by the private crew under Axiom’s management.
Building toward a commercial space station
According to Axiom, Ax-4 is a “stepping stone” in their ongoing efforts to develop Axiom Station, which the company intends to be the world’s first commercial space station. Through missions to the ISS, Axiom is building experience in space operations and mission management from its Houston control center, which may inform plans for a commercial station.
“We’ve got to get the [new] station up and running before the ISS is decommissioned,” Whitson told Time magazine. “That push for…expansion in space is important from a technology perspective [and] from a space power perspective.”
Axiom plans to launch the first module of its commercial station no earlier than 2027, with four or more subsequent modules to follow. The initial power, payload, and thermal module will first attach to the ISS before eventually detaching to fly freely.Looking ahead, Whitson emphasized the broader significance Axiom sees in its work: “We’re carrying the hopes of millions who dare to look up and imagine what’s possible. This is what the future of space looks like — bold, inclusive, and driven by purpose.”
