NASA said Friday that it is seeking proposals for the next two private astronaut missions to the International Space Station (ISS).

According to the space agency, the first mission will occur between the fall of 2022 and the middle of 2023. The second will take place between the middle and end of 2023.

The space agency announced inviting proposals from commercial space firms in the United States to make space more accessible than ever before.

STS-114 Steve Robinson on Canadarm2
(Photo: NASA / WikiCommons)

NASA's announcement comes after previously confirmed private astronauts to the International Space Station. NASA and Axiom Space agreed in May to send the first private astronauts to the International Space Station as early as January 2022.

A deadline of July 9, 2021, at 5 p.m. EDT, has been set for new mission proposals.

After the space shuttle program ended in 2011, said NASA requested commercial businesses to create a system to transport humans to the International Space Station. SpaceX's Crew Dragon capsule and Falcon 9 rocket were the first successful systems to emerge, with three crewed flights launched since the first in May 2020.

The missions are part of NASA's long-term plans to boost commercial space activities. The agency will host up to two private astronaut trips to the International Space Station each year.

ALSO READ: NASA Offers $400 Million to Help Private Companies Create New Space Stations

What Is A Private Astronaut Mission?

NASA describes private astronaut missions as privately funded, fully commercial to enable launch vehicle to enable tourism, outreach, commercial research, and approved commercial and marketing activities on the space station."

"This year is truly a renaissance for human spaceflight both as we fly NASA and international partner astronauts on US commercial crew spacecraft to the International Space Station and also as we see the expansion of private astronaut missions," said Phil McAlister, director of commercial spaceflight development in a statement on NASA's website per

He believes that when more people travel to space and accomplish more things during their missions, it will entice even more people to participate in activities in low-Earth orbit (LEO). It represents the expanding demand that he predicted when he started the Commercial Crew Program ten years ago.

According to NASA, LEO comprises Earth-centered orbits with an altitude of 2,000 km (1,200 miles) or less.

The two new missions are expected to last up to 14 days, according to NASA.

NASA Private Missions: What Does Axiom Space Aim to Do?

The long-term ambition of Axiom Space is to develop its own habitat that will be tethered to the International Space Station. This would be the beginning point for a new, private space station that would be operational long after the ISS is retired.

"We're talking about building a thriving home in space that benefits every human everywhere," Christian Maender, director of in-space manufacturing and research at Axiom Space, told Inverse.

While Axiom Space has a deal with SpaceX and NASA to support the Ax-1 mission, the company has only a deal with SpaceX for the remaining three flights. For Ax-2 and later missions, it has yet to reach an agreement with NASA.

RELATED ARTICLE: Space Tourism on the Rise: Are Other Passengers of SpaceX Considered "Astronauts"?  

Check out more news and information on Space on Science Times.