SEATTLE — NASA has selected Axiom Space to carry out the fourth in a series of private astronaut missions to the International Space Station in 2024.

NASA announced Aug. 3 it selected the Houston-based company for the mission, currently scheduled for no earlier than August 2024. The four-person mission, flying on a SpaceX Crew Dragon spacecraft, will spend up to two weeks docked to the station.

NASA had previously selected Axiom for three private astronaut missions to the station. The Ax-1 mission went to the station in April 2022, followed by Ax-2 in May 2023. NASA selected Axiom for the third mission, Ax-3, in March, and the agency said at the time it was in negotiations with an unnamed company for the fourth mission.

At the time of the announcement of Ax-3, NASA and Axiom Space said that mission was planned for as soon as November 2023. However, in a speech at the ISS Research and Development Conference Aug. 1, Dana Weigel, NASA ISS deputy program manager, said the mission was now scheduled for early 2024. The agency tweeted Aug. 2 that a revised launch date of no earlier than January 2024 “allows for teams to collaborate on the integration of the mission’s scientific research priorities.”

Neither NASA nor Axiom Space have announced who will fly on either Ax-3 or Ax-4. NASA regulations require private astronaut missions be commanded by former NASA astronauts with flight experience, leaving three seats available for paying customers. In January, Michael Suffredini, chief executive of Axiom, said he expected government-sponsored astronauts to be most of the customers of Ax-3 and Ax-4.

Axiom is using the private astronaut missions to gain experience ahead of installing its first commercial modules on the station as soon as late 2025. Those modules will form the core of a standalone space station the company plans to establish by the time the ISS is retired.

“These missions are instrumental in expanding commercial space activities and access to space for individuals and nations around the world, as well as developing the knowledge and experience needed to normalize living and working in microgravity,” Suffredini said in a statement about the Ax-4 award.

The private astronaut missions are part of NASA’s ISS transition strategy, supporting the development of commercial space stations that will succeed the ISS around 2030. Phil McAlister, director of commercial space at NASA Headquarters, described the Ax-4 award in an agency statement as “another milestone in our efforts to transition low Earth orbit from primarily a government-sponsored activity to one where NASA is one of many customers.”

That approach has the support of NASA’s Aerospace Safety Advisory Panel, an independent safety committee. During an Aug. 3 public meeting, panel member Mark Sirangelo noted the Ax-2 mission completed a “full manifest of science, outreach and commercial activities” and was able to return more than 135 kilograms of cargo for NASA.

“We think this whole mission seems to have gone considerably more smoothly” than the first mission, he said of Ax-2. “You can see very good progress in these private astronaut missions.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...