Private Ax-1 astronauts return to Earth, ending historic SpaceX mission

The first-ever all-private astronaut mission to the International Space Station is in the books.

A SpaceX Dragon capsule carrying the four crewmembers of the Ax-1 mission splashed down in the Atlantic Ocean off the coast of Jacksonville, Florida today (April 25) at 1:06 p.m. EDT (1706 GMT), bringing the groundbreaking 17-day flight to a close.

"On behalf of the entire SpaceX team, welcome back to planet Earth," a SpaceX mission communicator told the Ax-1 crew just after splashdown.

Live updates: Ax-1 private mission to space station
Related: Axiom Space: Building the off-Earth economy

Making history

Ax-1 was organized by the Houston company Axiom Space and commanded by former NASA astronaut Michael López-Alegría, who is now Axiom's vice president of business development. He was joined on the mission by three paying customers — American Larry Connor, Canadian Mark Pathy and Israeli Eytan Stibbe, each of whom is thought to have paid about $55 million for his seat. 

Stibbe is the second Israeli ever to reach space. He was friends with the first — Ilan Ramon, who died along with his six crewmates in the space shuttle Columbia disaster on Feb. 1, 2003.

Paying customers have visited the International Space Station (ISS) before; indeed, Japanese billionaire Yusaka Maezawa and video producer Yozo Hirano lived aboard the orbiting lab for 11 days just this past December. But such previous flights had always been commanded by a government astronaut — namely, a cosmonaut employed by Russia's federal space agency, Roscosmos. Ax-1 coordinated with NASA and ISS officials, but its crewmembers were all private civilians.

You could also call the Ax-1 astronauts space tourists, but they would dispute that characterization.

Ax-1 is "like a NASA mission to the ISS, and by no means what I equate to a leisurely, tourism adventure," López-Alegría told Space.com during a conversation last year, citing the extensive preparation required and the science work the crewmembers would be doing in orbit. "It's much more than that."

Ax-1 is not the first-all private crewed orbital mission of any kind, by the way. That distinction goes to Inspiration4, another SpaceX flight that spent nearly three days circling Earth last September. 

Photos: The first space tourists

Lots of science work

Ax-1 lifted off atop a SpaceX Falcon 9 rocket on April 8 and docked with the ISS a day later.

While living on the orbiting lab, the private astronauts conducted more than 25 science experiments in a range of fields, from human health and medicine to Earth observation and physical science.

For example, Connor investigated the relationship between heart health and senescent cells (cells that have stopped dividing). And researchers will study magnetic resonance imaging (MRI) scans of him taken both pre- and post-flight, to gain a better understanding of how space missions affect brain and spinal tissue. Connor is working on these projects with the Mayo Clinic and the Cleveland Clinic, contributing to lines of research that he has helped fund over the past decade.

Among Pathy's projects were Earth-observation work designed to shine light on the impacts of climate change and urbanization, as well as research on sleep disturbances and chronic pain for the Montreal Children's Hospital.

Stibbe worked with the Ramon Foundation, a nonprofit organization named after his friend, and the Israel Space Agency on a variety of investigations.

"The experiments are innovative and trailblazing, arising from diverse disciplines — astrophysics, agriculture, optics, communication, biology, healthcare, neurology and ophthalmology — and were chosen based on their potential impact on research and innovative approach," Inbal Kreiss, chair of the scientific and technological committee and head of innovation of systems missiles and space group at Israel Aerospace Industries, the nation's state-owned aerospace company, said in an Axiom Space statement late last year.

The Ax-1 crewmembers ended up having substantially more time to perform these experiments than they initially thought. The mission was supposed to leave the ISS on April 19 and return to Earth a day later, but bad weather boiled up in the splashdown zone off the Florida coast and persisted, delaying the Dragon's departure until Sunday night (April 24).

And, in case you were wondering: Axiom Space did not have to pay for the extra five days aboard the orbiting lab.

The contract Axiom signed with NASA "includes an equitable balance to cover Ax-1 for a sufficient number of contingency days," NASA public affairs officer Gary Jordan told Space.com via email. 

"Knowing that International Space Station mission objectives like the recently conducted Russian spacewalk or weather challenges could result in a delayed undock, NASA negotiated the contract with a strategy that does not require reimbursement for additional undock delays," he added.

The delay did affect another astronaut mission, however — SpaceX's Crew-4, which will send three NASA astronauts and one European Space Agency astronaut to the ISS for a lengthy stay. Crew-4 was supposed to launch from NASA's Kennedy Space Center in Florida over the weekend, but that liftoff will now occur no earlier than Wednesday (April 27); NASA officials have said they want about two days between Ax-1's splashdown and Crew-4's launch to allow for data analysis and other preparations.

Just the beginning

Ax-1 will be just the beginning for Axiom Space, if all goes according to plan. The company has booked several additional missions to the orbiting lab, which will all be flown by SpaceX. 

The next one, Ax-2, is scheduled to launch later this year and will be commanded by former NASA astronaut Peggy Whitson, who has spent more time in space than any other American. Like López-Alegría, she now works for Axiom, serving as the company's director of human spaceflight.

But Axiom has bigger plans still. Starting in late 2024, the company intends to launch a series of modules to the ISS. These connected modules will eventually detach and fly freely, becoming the first privately operated space station in Earth orbit. Axiom believes that there will be high demand for this commercial outpost, and that it could end up jump-starting an off-Earth manufacturing economy.

"On the ISS, a company could only fly an experiment; even if the experiment was successful, there was not a place for that company to go to make the product at scale," Axiom Space chief technology officer Matt Ondler told Space.com late last year. "A commercial space station like Axiom's will provide that opportunity and therefore I believe we will see all sorts of ideas and products we can't imagine today."

Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or on Facebook.