WASHINGTON: SpaceX is preparing to carry four astronauts to a crowded International Space Station on Thursday, in the second routine mission since the United States resumed crewed space flight, and the first with a European.

Liftoff is planned for 6:11 am Eastern Time (1011 GMT) on April 22, from NASA's Kennedy Space Center in Florida.

The mission, called Crew-2, involves US astronauts Shane Kimbrough and Megan McArthur, along with the Japan Aerospace Exploration Agency (JAXA)'s Akihiko Hoshide, and the European Space Agency (ESA)'s Thomas Pesquet.

All have flown to space previously.

ESA has dubbed the mission "Alpha" after the star Alpha Centauri, the closest star system to our own.

Elon Musk's SpaceX has firmly established itself as NASA's favored transportation provider as the agency waits on Boeing's troubled Starliner capsule to carry out key tests.

SpaceX's first crewed test flight in May 2020 ended nine years of American reliance on Russian rockets for rides to the ISS following the demise of the Space Shuttle program.

Thursday's flight will reuse the booster rocket used in the Crew-1 mission -- a first -- and the Crew Dragon capsule will be the same as that used in the test mission.

Speaking to reporters ahead of the mission, Pesquet said his participation underscored Europe's commitment to space flight.

"It means a lot for us as an agency because we've been part of the ISS program for 20 years now and we intend to be part of what's coming next," said the Frenchman, referring to future partnerships including the Artemis program to the Moon.