Axiom's four-man team lifts off, riding atop a SpaceX Falcon 9 rocket in the first private astronaut mission to the International Space Station, from NASA's Kennedy Space Center in Cape Canaveral, Florida, U.S. April 8, 2022.
Axiom's four-man team lifts off, riding atop a SpaceX Falcon 9 rocket in the first private astronaut mission to the International Space Station, from NASA's Kennedy Space Center in Cape Canaveral, Florida, U.S. April 8, 2022. Reuters / STEVE NESIUS

The first all-private astronaut team ever flown aboard the International Space Station (ISS) splashed down in the Atlantic off Florida's coast on Monday, completing a two-week science mission hailed as a milestone in commercial spaceflight.

The SpaceX crew capsule carrying the four-man team, led by a retired NASA astronaut who is now vice president of the Texas company behind the mission, Axiom Space, parachuted into the sea after a 16-hour descent from orbit.

The splashdown, carried live by a joint Axiom-SpaceX webcast, was originally planned for last Wednesday, but the return flight was delayed due to unfavorable weather.

The return from orbit followed a plunge through Earth's atmosphere generating frictional heat that was expected to have sent temperatures surrounding the outside of the capsule soaring to 3,500 degrees Fahrenheit (1,927 degrees Celsius). The astronauts' flight suits are designed to keep them cool as the cabin heats up.

Two sets of parachutes released in the final stage of the capsule's descent slowed its fall to about 15 miles per hour (24 km per hour) before splashdown off the coast of Jacksonville.

Axiom, SpaceX and NASA have touted the occasion 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.

The mission's crew was assembled, equipped and trained entirely at private expense by Axiom, a five-year-old venture based in Houston and headed by NASA's former ISS program manager Michael Suffredini. The company also is under contract with NASA to build the first commercial addition to and ultimate replacement for the space station.

SpaceX, the private launch service founded by Tesla Inc electric carmaker CEO Elon Musk, supplied the Falcon 9 rocket and Crew Dragon capsule that carried Axiom's team to and from orbit, controlled the flight and handled the splashdown recovery.

NASA furnished the launch site at its Kennedy Space Center in Cape Canaveral, Florida, and assumed responsibility for the Axiom crew while they were aboard the space station. The space agency's ISS crew members also pitched in to assist the private astronauts when needed.

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

Joining them as "mission specialists" were investor-philanthropist and former Israeli fighter pilot Eytan Stibbe, 64, and Canadian businessman and philanthropist Mark Pathy, 52.

Launched from NASA's Kennedy Space Center on April 8, they spent 15 days aboard the space station with the seven regular, government-paid ISS crew members: three American astronauts, a German astronaut and three Russian cosmonauts.

The ISS has hosted several wealthy space tourists from time to time over the years.

But the Axiom quartet was the first all-commercial team ever welcomed to the space station as working astronauts, bringing with them 25 science and biomedical experiments to conduct in orbit. The package included research on brain health, cardiac stem cells, cancer and aging, as well as a technology demonstration to produce optics using the surface tension of fluids in microgravity.

It was the sixth human spaceflight for SpaceX in nearly two years, following four NASA astronaut missions to the ISS and the "Inspiration 4" flight in September that sent an all-private crew into Earth orbit for the first time, though not to the space station.

SpaceX has been hired to fly three more Axiom astronaut missions to ISS over the next two years. The price tag for such outings is 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 station is retired around 2030.