SEVILLE, Spain — NASA announced Nov. 26 that it is interested in buying a seat on a future commercial mission to the International Space Station, the latest move in the agency’s broader low Earth orbit commercialization efforts.

In a procurement filing, NASA said it seeks to buy a seat on a short-duration commercial mission to the ISS no later than 2024. That seat would be one of up to four on a dedicated commercial mission to the station lasting between 15 and 30 days.

NASA opened the door to such dedicated commercial missions in June as part of its LEO commercialization strategy. That plan allows for two “private astronaut missions” to the station each year, starting as soon as 2020, carrying as many as seven people per flight. At the time, though, NASA didn’t indicate it planned to be a customer for such missions.

“NASA’s purchase of a seat on a future private astronaut mission of no more than four total crew members helps both foster the low Earth orbit economy as well as provides NASA an additional way to meet its needs for research aboard the International Space Station,” the agency said in a Nov. 26 statement about its plans.

In that statement, the agency argued that a short-duration mission would complement existing long-duration missions of six months or more. “In preparation for NASA’s plans for human missions to the Moon and Mars, NASA has identified a requirement to use missions of varying length on which it collects standard data to establish profiles of human physiological, behavioral, and psychological variables of importance for ensuring astronaut health and performance during future long-duration deep space missions.”

Two companies would have the capability of performing such missions through 2024: Boeing and SpaceX, using the commercial crew vehicles they are developing for routine transport of NASA and other government astronauts to and from the station. Neither company has formally announced plans for such missions, which would be in addition to their NASA missions they are currently under contract for, although in the past they have expressed an interest in additional missions beyond NASA.

Other companies are seeking business for private astronaut missions, ultimately to commercial space stations. In a recent newsletter, Axiom Space announced it had sold its first seat to an unidentified customer in January, a deal it said had a list price of $55 million. The company added it is “working with multiple additional candidates from missions to ISS and Axiom Station,” the latter its proposed private space station.

NASA stated in its announcement it is only seeking white papers from potential mission providers at this time. A formal request for proposals is expected in March 2020.