Blue Origin, the space company owned by Jeff Bezos, the founder of Amazon, is teaming up with other firms to build a space station in Earth orbit. The group announced its plans on Monday, revealing the latest concept for a privately built orbital outpost that could replace or complement the International Space Station.

The influx of private space station proposals comes as NASA seeks a replacement for the 20-year-old, $100 billion laboratory in space, which is showing signs of its age. Whether any of the low-Earth orbit concepts will be ready to house astronauts by the time funding for the International Space Station lapses around 2030 is unclear, and depends largely on the funding NASA is able to get from Congress. The agency plans to allocate up to $400 million to private space companies to kick-start construction, eventually partnering with private operators the way it now relies on companies like Elon Musk’s SpaceX to get cargo and astronauts to and from the I.S.S.

The proposal by Blue Origin and its partners, called Orbital Reef, only exists in digital animations and drawings, and executives said it could be built by the end of the decade. It will have competition, from the very real Tiangong station that China expects to finish as soon as next year, as well as other proposed private outposts. Lockheed Martin and Nanoracks, a firm that facilitates research on the I.S.S., unveiled last week their own space station called Starlab. And Axiom Space, another entrant, has the go-ahead to launch the beginnings of a free-flying base that will first attach to the International Space Station.

The Orbital Reef project is expected to draw hefty financial backing from Mr. Bezos, who has committed to spending $1 billion per year of his fortune on Blue Origin, and has described a goal of creating the conditions for millions of people to live and work in space. The company, founded in 2000, has launched customers on short, up-and-down tourist flights to the edge of space. But it has not yet achieved other goals, such as building an orbital rocket or winning a NASA contract to build a lunar lander for astronauts.

Key partners in the project are Sierra Space, which has been building its own space station idea for years, and Boeing, the aerospace giant that has built and managed American segments on the I.S.S. for NASA.

Their proposed space station aims to “generate new discoveries, new products, new forms of entertainment and global awareness of Earth’s fragility and interconnectedness,” Brent Sherwood, a Blue Origin vice president, told reporters on Monday from a space conference in Dubai. The station’s most basic design resembles the current space station’s, with roughly 90 percent of the interior volume and a capacity to hold up to 10 astronauts (the I.S.S. typically houses seven, but has been home to as many as 13 at once).

Sierra Space will contribute its LIFE habitat, an inflatable module that launches to space in a condensed form, then expands in space into a marshmallow-shaped pod with a thick fabric for walls. The company could also use its Dream Chaser space plane to send astronauts to and from the station. And Boeing’s Starliner capsule, an astronaut taxi marred by a hodgepodge of technical issues, is also expected to carry visitors to the Orbital Reef.

Few companies appear financially capable of pulling off the construction of a space station — a tall feat executed only by governments, which have typically been motivated more by international relations than profit. The proposed stations, including Orbital Reef, aim to generate revenue from wealthy tourists as well as academic and corporate researchers. But specific metrics on that demand remain blurry, executives said.

Another customer base for the station will be government space agencies. The Orbital Reef team is already talking with other countries, Janet Kavandi, Sierra Space’s president and a former astronaut, said in an interview, highlighting the space program of the United Arab Emirates.

“The U.A.E. is very interested, and there’s been a lot of discussion about them partnering with us over the past few months,” Ms. Kavandi said, speaking in Dubai at the annual International Astronautical Congress. “We will have discussions with other partners as well, many of whom are partners that NASA has on the I.S.S. today, but also partners that have not flown in space in the past,” she added.

Mike Gold, an executive vice president at Redwire Space, another firm partnering with Blue Origin, said elements of the new space station could be a test bed for technologies that will eventually help astronauts live on the moon.

Orbital Reef is Blue Origin’s second major partnership with other space firms. The company teamed up with Lockheed Martin, Northrop Grumman and Draper in 2019 on a lunar lander proposal, called Blue Moon, for NASA. But NASA chose the lander pitched by SpaceX.

Mr. Sherwood declined to say how much Orbital Reef will cost to build, or how much Mr. Bezos plans to contribute. Much of the cost and scope of the station, Mr. Sherwood and others said, depends on how much NASA is able to spend within the new program to help fund private space station proposals.

“We are committed to making this happen regardless” of what NASA is able to fund, Mr. Sherwood said.