Commercial Crew Program
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, and NASA plans to add Boeing when its Boeing Starliner spacecraft becomes operational no earlier than 2025. NASA has contracted for six operational missions from Boeing and fourteen from SpaceX, ensuring sufficient support for ISS through 2030. The spacecraft are owned and operated by the vendor, and crew transportation is provided to NASA as a commercial service. Each mission sends up to four astronauts to the ISS. 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