The first all-private astronaut team ever to fly aboard the International Space Station (ISS) departed the orbiting outpost on Sunday to begin a descent back to Earth, capping a two-week science mission hailed as a milestone in commercial spaceflight.

A SpaceX Crew Dragon capsule carrying the four-man team from the Houston-based startup company Axiom Space undocked from the ISS at about 9:10 p.m. EDT (0110 GMT Monday) to embark on a 16-hour return flight, a live NASA webcast showed.

The Axiom astronauts, garbed in their helmeted white-and-black spacesuits, were seen strapped into the crew cabin shortly before the spacecraft separated from the station, orbiting some 250 miles (420 km) above Earth. A couple of brief rocket thrusts then pushed the capsule safely clear of the ISS.

If all goes smoothly, the Dragon capsule, dubbed Endeavour, will parachute into the Atlantic off the coast of Florida on Monday around 1 p.m. EDT (1700 GMT).

The flight home was postponed for several days due to unfavorable weather at the splashdown zone, extending the Axiom crew's stay in orbit well beyond its original departure date early last week.

The multinational team was led by Spanish-born retired NASA astronaut Michael Lopez-Alegria, 63, Axiom's vice president for business development. Larry Connor, 72, a real estate-technology entrepreneur and aerobatics aviator from Ohio, was the second in command.

Rounding out the Ax-1 crew were investor-philanthropist and former Israeli fighter pilot Eytan Stibbe, 64, and Canadian businessman and philanthropist Mark Pathy, 52, both serving as mission specialists.

Launched from NASA's Kennedy Space Center on April 8, they spent two weeks aboard ISS with the seven regular, government-paid crew of the space station: three American astronauts, a German astronaut and three Russian cosmonauts.

The Axiom quartet became the first all-commercial astronaut team ever launched to the space station, taking with them equipment for two dozen science experiments, biomedical research and technology demonstrations to conduct in orbit. 

Axiom, NASA and SpaceX have touted the mission as a turning point in the expansion of privately funded space-based commerce, constituting what industry insiders call the "low-Earth orbit economy," or "LEO economy" for short.

Ax-1 marks the sixth human spaceflight SpaceX has launched in nearly two years, following four NASA astronaut missions to the ISS, plus the Inspiration 4 flight in September, which sent an all-civilian crew into Earth orbit for the first time, though not to the space station.

SpaceX, the private rocket company founded by Tesla Inc electric carmaker CEO Elon Musk, has been contracted to fly three more Axiom astronaut missions to the ISS over the next two years. The price tag for such outings remains high.

Axiom charges customers $50 million to $60 million per seat, according to Mo Islam, head of research for the investment firm Republic Capital, which holds stakes in both Axiom and SpaceX.

Axiom also was selected by NASA in 2020 to build a new commercial addition to the space station, which a U.S.-Russian-led consortium of 15 countries has operated for more than two decades. Plans call for the Axiom segment to eventually replace the ISS when the rest of the space station is retired around 2030.