WASHINGTON — Sierra Space has raised $290 million in a round led by Japanese investors, providing the company with additional funding to accelerate work on its Dream Chaser vehicle and commercial space stations.

The company announced the Series B round Sept. 26, led by three Japanese investors: MUFG, Japan’s largest bank; trading company Kanematsu Corporation; and Tokio Marine & Nichido, the country’s largest property and casualty insurer. Existing investors also participated in the round, which values Sierra Space at $5.3 billion.

Sierra Space raised $1.4 billion in a Series A round in November 2021. The combined Series A and B rounds is the largest for a commercial space company, Sierra Space stated in its announcement of the new round.

“As we transition our revolutionary Dream Chaser spaceplane into operations for NASA cargo resupply missions to the International Space Station, we focus our capital deployment to the development and operations of the first commercial space station — the next step in our in-space infrastructure — the growth of our national security offering and scaling our space systems components business,” Tom Vice, chief executive of Sierra Space, said in a statement.

Sierra Space is best known for its Dream Chaser vehicle, an initial cargo version of which is slated to launch next year on the second flight of United Launch Alliance’s Vulcan Centaur. The company has plans for a crewed version of the vehicle as well as one for unspecified national security applications.

Sierra Space is also partnered with Blue Origin and other companies on the Orbital Reef commercial space station, offering Dream Chaser as well as an inflatable habitat module called Large Integrated Flexible Environment (LIFE). The company recently completed a successful burst test of a subscale model of LIFE, allowing the company to proceed to tests of a full-scale version.

Junichi Hanzawa, president and chief executive of MUFG, said in a statement that his bank was interested in Sierra Space’s commercial space station efforts. “MUFG has decided to invest in low Earth orbit to support commercialization, the creation of new industries, and the resolution of social issues,” he said.

Sierra Space plans to work with its new investors to expand its presence in the Japanese market. That includes participation in an ongoing study by the Japanese space agency JAXA on low Earth orbit commercialization as JAXA prepares for the end of the International Space Station at the end of the decade. Sierra Space has also been examining the feasibility of using Japan’s Oita Airport as a Dream Chaser landing site.

Privately held Sierra Space has offered few details about its financials. At an investor conference in June, Vice said the company had about $260 million in revenue in 2022 and a backlog of $3 billion. That backlog is now $3.4 billion, according the company statement about the Series B round.

Vice said then that Sierra Space is a “revenue-generating, profit-generating company,” but did not disclose how much profit it made in 2022. The company, he argued, has “a very strong balance sheet and long-term investors that give us the capital that allows us to invest in being a category winner.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...