Saudi Arabia is planning to launch two astronauts to the International Space Station aboard a space capsule from Elon Musk's SpaceX, sources say.
The deal makes the kingdom the latest Gulf nation to strengthen ties with private US space companies.
The sources said the deal was signed privately this year with Houston's Axiom Space, which arranges and manages private missions to space on US spacecraft for researchers and tourists.
Under the deal, two Saudi astronauts will ride SpaceX's Crew Dragon capsule to the space station for about a week early next year, the sources said.
The two would be the first from their country to go into space aboard a private spacecraft.
Axiom had no immediate comment. Officials with the Saudi Space Commission, Riyadh's space agency founded in 2018, were not immediately available.
Private US companies have increasingly played a key role in sending astronauts to the space station as Nasa turns its focus to returning humans to the Moon and commercialising flights in low-Earth orbit.
The deal is the latest to put companies such as Axiom in a unique role of diplomacy long dominated by government agencies including Nasa.
The space station is a football field-sized laboratory about 400 kilometres above Earth that has held international crews of astronauts for more than 20 years.
The Saudi astronauts will join two previously announced Americans — retired Nasa astronaut Peggy Whitson and race car driver and investor John Shoffner — the sources said.
The mission, called Ax-2, will be the second spaceflight arranged by Axiom.
The private astronauts aboard Ax-2 have yet to be approved by a Nasa-chaired panel of the space station's participating stakeholders and countries, such as Russia, Canada, Japan and the European Space Agency, a US official said.
The official said the mission was likely to receive approval.
For Axiom and other space companies, making deals with foreign governments is considered vital to sustaining a business centred on putting people in space — a luxury for wealthy adventure seekers and a source of national prestige and inspiration for aspiring space powers such as Saudi Arabia.
Axiom launched its first private mission to the space station in April, sending a four-man crew, including a Canadian investor and an Israeli businessman, aboard a SpaceX Crew Dragon capsule.
And Axiom on Monday announced a deal with Turkey to launch the country's first two astronauts into space in late 2023. That will probably be for mission Ax-3, a source said.
Axiom's astronaut flight business is crucial experience for the company's broader goals of establishing its own private space station by the middle of the decade.
It plans to first attach modules to the ISS before splitting off into a fully private structure when the international laboratory is retired about 2030.
The value of Axiom's Saudi agreement was not clear. Each Crew Dragon seat on Axiom's first mission sold for $55 million.