This is unprecedented: four American citizens will stay for three days in space without being accompanied by a professional astronaut.
Operated by SpaceX, the Inspiration4 mission will take off this Thursday morning, between 2:02 am and 7:02 am, Paris time, from the Kennedy Space Center in Florida.
The Falcon 9 rocket will place the Crew Dragon spacecraft in orbit 590 km above the blue planet.
An event of which SpaceX will broadcast live images.
The video is to begin four hours before takeoff.
The crew is heterogeneous: Jared Isaacman, businessman, who commands and finances the mission; Chris Sembroski, former US Air Force and aeronautical engineer; Sian Proctor, professor of geology and specialist in science education; Hailey Arceneaux, who recovered from pediatric cancer and will become at 29 the youngest American astronaut. The purpose of the mission is to raise awareness and provide funds to St Jude Children's Research Hospital, a hospital for children with cancer located in Memphis, Tennessee.