The Commercial Crew Program (CCP) provides commercially operated crew transportation service to and from the International Space Station (ISS) under contract to NASA, conducting crew rotations between the expeditions of the International Space Station program. American space manufacturer SpaceX began providing service in 2020, using the Crew Dragon spacecraft,[69] while Boeing’s Starliner spacecraft provided service in 2024. It was on contract for 6 missions, but after the first mission nearly ended in disaster and left the two astronauts stranded on the ISS for six months, NASA froze its contract with Boeing.[70][71][72][73] NASA has contracted for six operational missions from Boeing and fourteen from SpaceX, ensuring sufficient support for ISS through 2030.[74]

The spacecraft are owned and operated by the vendor, and crew transportation is provided to NASA as a commercial service.[75] Each mission sends up to four astronauts to the ISS, with an option for a fifth passenger available. Operational flights occur approximately once every six months for missions that last for approximately six months. A spacecraft remains docked to the ISS during its mission, and missions usually overlap by at least a few days. Between the retirement of the Space Shuttle in 2011 and the first operational CCP mission in 2020, NASA relied on the Soyuz program to transport its astronauts to the ISS.

A Crew Dragon spacecraft is launched to space atop a Falcon 9 Block 5 launch vehicle and the capsule returns to Earth via splashdown in the ocean near Florida. The program’s first operational mission, SpaceX Crew-1, launched on November 16, 2020.[76] Boeing Starliner operational flights will now commence with Boeing Starliner-1 which will launched atop an Atlas V N22 launch vehicle. Instead of a splashdown, Starliner capsules return on land with airbags at one of four designated sites in the western US.[77]