It will be the first manned orbital mission in the history of human spaceflight to be crewed only by tourists and other passengers who are also not professional astronauts, SpaceX has said.
The mission will be launched from the Kennedy Space Center in Florida on Wednesday evening or night at a time from 8:02 p.m. and 1:02 a.m. Eastern Time (ET), provided storms or other weather problems do not delay it, SpaceX said.
The mission is scheduled to stay in orbit for three days before re-entering the atmosphere for a sea splashdown in the Atlantic Ocean east of Florida, according to published reports. The spacecraft will complete each orbit of the earth in about 90 minutes and will orbit more than 100 miles higher than the International Space Station.
The Crew Dragon is also equipped with a specially-designed zero-gravity toilet, the reports said.
The mission is financed by US billionaire Jared Isaacman, 38 who created the payment processing company Shift4. Isaacman personally selected Hayley Arceneaux, a cancer survivor from Memphis, Tennessee, for the flight. She is now a physician's assistant at St. Jude's Hospital in Memphis.
Arcenaux will be the first person with a prosthetic body part to participate in any space mission: She will also be the flight's chief medical officer.
Sian Proctor, 51, a geologist and educator, was chosen for the mission from a presentation she posted on social media. She will be only the fourth US African-American woman to travel in space in the 60-year history of US human space flight.
Chris Sembroski, 42, from Seattle, Washington, worked for defense contractor Lockheed Martin and had the most convoluted route to the space flight. A friend of his won the flight seat in a raffle but decided not to go and passed on the ticket to him.
The first civilian to buy a private flight into space was US billionaire investment manager Dennis Tito who bought an eight-day visit on the International Space Station 20 years ago. He was flown there and back on a Russian Soyuz spacecraft.
Published estimates put the likely cost of Wednesday's mission at more than $200 million.