June 26, 2025 Ax-4 crewmembers onboard the "Grace" Crew Dragon capsule. From left: Tibor Kapu, Shubhanshu Shukla, Peggy Whitson and Sławosz Uznański-Wiśniewski. Credit: Axiom Space/NASA HOUSTON—Crewmembers on Axiom Space's fourth private astronaut mission (Ax-4) were welcomed onboard the International Space Station (ISS) early June 26, following an autonomous docking of the four-person SpaceX Grace Crew Dragon capsule to the space-facing port of the orbital lab's U.S. segment Harmony module. The 6:31 a.m. EDT docking followed a successful liftoff atop a Falcon 9 of the Grace capsule on its inaugural mission from NASA's Kennedy Space Center on June 25 at 2:31 a.m. EDT. The docking brings to 11 the number of astronauts and cosmonauts from six countries living and conducting research and technology development activities, as well as daily maintenance, on the ISS. "We're looking forward to seeing you guys," Ax-4 commander Peggy Whitson, Axiom's director of human spaceflight and a record-setting retired NASA astronaut, radioed the ISS' seven-member crew as the Crew Dragon spacecraft neared the orbital lab. "We're looking forward to seeing you, too," NASA astronauts Anne McClain and Nicole Ayers responded from the ISS as they monitored Grace's approach. Whitson, Ax-4 pilot Shubhanshu Shukla, of the Indian Space Research Organization; mission specialist Sławosz Uznański-Wiśniewski, a European Space Agency project astronaut from Poland; and mission specialist Tibor Kapu, of Hungary, have trained to conduct about 60 research projects sponsored by 31 countries during a stay planned for up to 14 days. Two dozen of the projects are sponsored by the ISS National Laboratory, which provides science access to the ISS to academia and commercial ventures. The Ax-4 visitors were greeted by the ISS Expedition 73 crew, which is commanded by the Japan Aerospace Exploration Agency's Takuya Onishi and includes NASA astronauts McClain, Ayers and Jonny Kim and Russian cosmonauts Kirill Peskov, Sergey Ryzhikov and Alexey Zubritsky. "The mission is really jam-packed with really interesting and exciting science," said Lucie Low, Axiom Space's chief scientist. "We have everything from human research to understand how the human body reacts to space. We have some really fun life sciences experiments looking at growing plants of all kinds. We have some physical sciences. We have lots of technology demonstrations, and my favorite, lots of Science, Technology, Engineering and Mathematics [STEM] outreach events." The STEM outreach will involve students in the countries represented by the Ax-4 crew. Low also singled out an ongoing Axiom Space mission research effort trailing back to the Ax-1 mission in April 2022 and led by the University of California, San Diego's Sanford Stem Cell Institute. The effort includes the launch and return to Earth of cancer cells to evaluate how they respond to the space environment. The Ax-4 version includes a study of a new cancer medication that is about to enter a critical trial phase, according to Low. The Ax-4 crew is scheduled to wrap up their mission to the ISS onboard Grace with a parachute-assisted splashdown and recovery in the Pacific Ocean off the coast of California.