SpaceX has secured orders for three private flights to the International Space Station by 2023

The US Space exploration technology company SpaceX has signed a so-called "volume deal" with private Space startup Axiom Space to carry out three private flights to the International Space Station by 2023 using its Crew Dragon spacecraft.

While the terms of the agreement have not yet been disclosed, it marks one of the biggest deals to date in the booming private space industry and adds to the space station's busy schedule for years to come.

Ahead of the three missions, which will take place around six months apart, AXIOM will use its first manned Dragon spacecraft to transport an "all-civilian" crew to the International Space Station in January 2022, on a mission known as AX-1. AX-2, AXIOM's second manned mission, will be led by former NASA astronaut Peggy Whitson. The crew of the AX-3 and AX-4 has not yet been announced. All flights will include stops at the International Space Station.

Axiom declined to reveal the exact value of the SpaceX deal, which has been in the works for months and was formally signed in recent weeks. SpaceX did not respond to an email seeking comment. The timing and other details of the mission need to be approved by NASA, which manages the ISS schedule.

"A new era of human spaceflight has arrived," Gwynne Shotwell, SpaceX president, said in a statement. The growing partnership between Axiom and SpaceX will provide more people with access to space and help humanity on the path to a multi-planetary species." She was apparently referring to the goal of Elon Musk, the founder of SpaceX, to colonize Mars.

Houston-based Axiom was founded in 2016 by Mike Suffredini, a former senior manager of Nasa's space station programme. For Axiom, these initial manned missions will serve as "pioneering missions" for the company's core project to build a commercial space station module, the first of which is scheduled to be installed in 2024. These missions will keep the company on track for the commercial space station program, Safredini added.

"All four civilian astronauts will undergo joint Nasa-SpaceX commercial astronaut training, in which SpaceX will provide Falcon 9 rocket and Dragon training, emergency preparedness training, spacesuit and spacecraft entry and exit drills, and some and all simulations," SpaceX said in a statement.

The Dragon spacecraft was developed by SpaceX under a contract worth about $3 billion under NASA's Commercial Crew Program. The plan is aimed at reducing America's reliance on Russian spacecraft and returning astronauts to space from American soil. Since May 2020, SpaceX has sent three astronauts into space under the program, with four more on the way. Boeing is the second company to participate in Nasa's commercial astronaut programme, but its interstellar craft is far behind in development and is likely to launch its first manned mission before the end of the year.

SpaceX has won a major private flight deal to make three trips to the International Space Station by 2023

Four more private flights arranged by Axiom on top of SpaceX's commercial crew schedule will make the ISS schedule even busier. The International Space Station has only two docking ports, compatible with the Crew Dragon and Starline spacecraft. NASA says it will only allow private astronauts to travel to the International Space Station twice a year due to the early schedule of Starline flights, and it is unclear whether all four AXIOM missions will be approved. NASA did not immediately respond to an email seeking comment.

"We continue to be very busy on the International Space Station, and NASA's partnerships with commercial companies are changing the way we look at low Earth orbit," Joel Montalbano, NASA's International Space Station program manager, said Wednesday at a news conference about SpaceX's upcoming cargo launch.

The AX-1 isn't the first time SpaceX has launched a manned space mission staffed entirely by civilians. The billionaire Jared Isaacman has booked a flight aboard the Dragon, which he plans to launch in September, called Inspiration4. Instead of docking with the space station, Isaacman and his three companions will orbit the Earth in a spacecraft for three days and then return.

Meanwhile, the AX-1 isn't the first time space tourists have traveled to the International Space Station. Seven paying customers flew to the space station on Russian Soyuz spacecraft eight times between 2001 and 2009, including Charles Simonyi, who flew twice.

If all goes well, the Soyuz spacecraft will carry civilians to the International Space Station twice before the end of the year. Among them are Russian director Klim Shipenko and actress Yulia Peresild, who are scheduled to fly in September, and Japanese billionaire Yusaku Maezawa, who has booked flights for himself and his assistant Yozo Hirano for December.