The future of commercial research in low Earth orbit is on the clock.

For several years, NASA and the Center for the Advancement of Science in Space (CASIS), the non-profit organization that manages part of the station’s research facilities, have worked to stimulate interest in performing research on the International Space Station. That effort is still a work in progress, but it has shown promise based on experiments that have flown.

However, the ISS itself has a limited future. NASA and its partners have agreed to extend the station’s life to at least 2024, but its future beyond that is hazy. Part of that is linked to the station’s age, as engineering reviews conclude it could operate until 2028. There’s also a more pragmatic reason: getting the ISS off NASA’s books frees up funding to continue its Mars exploration plans.

So, at some point in the 2020s, that commercial research currently being fostered on the ISS will have to find a new home. Even before then, demand for the station’s facilities could exceed its capacity, particularly if the promise of microgravity research is finally realized.

The solution seems clear: develop a commercial space station of some kind, perhaps starting with a single module docked to the ISS, that can host research and other uses. But as interest grows in developing such stations, NASA has also come to a conclusion that there are ways it can help support their development, rather just waiting for one to show up in orbit.

“We’re looking really hard at what happens after the space station,” said Bill Gerstenmaier, NASA associate administrator for human exploration and operations, at a meeting of the NASA Advisory Council in July. “We started to hear from a lot of folks who wanted to attach modules to ports on the station, or they wanted to use some of the unique resources on the station.”

To assess how it might make that port, and other station resources, available to commercial users, NASA issued a request for information (RFI) in July, asking companies to describe their interest in adding a commercial module to the ISS. “NASA is making available a port, power, atmosphere; everything a private company could want from an infrastructure standpoint,” Gerstenmaier said.

NASA requested responses to the RFI by Aug. 12, and is now reviewing them. “We got a lot of feedback from companies that are interested in building commercial modules,” said Robyn Gatens, deputy director of the ISS at NASA Headquarters, at a Sept. 16 commercial space conference in Washington organized by Women in Aerospace.

She didn’t disclose who responded to the RFI, but the number of companies that appear interested in commercial modules is growing. That includes Bigelow Aerospace, a company established more than 15 years ago to create commercial space stations. It has flown several prototypes, including the Bigelow Expandable Activity Module, built under a NASA contract and flown to the station earlier this year. It currently occupies the docking port NASA is considering offering to commercial users.

Even before the NASA RFI, Bigelow was making its own unsolicited offer. At a press conference during the 32nd Space Symposium in Colorado Springs, Colorado, in April, company president Robert Bigelow said his company would have two of its B330 modules — so named because, when expanded, they have a volume of 330 cubic meters — ready for launch by 2020. One of them, he proposed, could be docked to the ISS, something he called the Expandable Bigelow Advanced Station Enhancement, or XBASE.

At the ISS Research and Development Conference in July in San Diego, organized by CASIS, Bigelow didn’t state whether Bigelow was planning to respond to the RFI, but said that the company had already submitted a proposal to install XBASE on the station. “We would be really excited to do that with NASA, and we gave them a tremendous deal,” he said in an interview.

Axiom Space is proposing to develop a commercial module that can be added to the International Space Station and later form the core of a commercial space station. Credit: Axiom

Axiom Space is proposing to develop a commercial module that can be added to the International Space Station and later form the core of a commercial space station. Credit: Axiom

Bigelow, though, has competition in the commercial space station business. In June, Michael Suffredini, the former NASA ISS program manager who left the agency nearly a year ago to take a position with Stinger Ghaffarian Technologies, announced the formation of a new venture, Axiom Space. It, too, has plans for commercial space stations, starting with a module attached to the ISS.

“What we would like to do is fly a module that begins its life at the International Space Station,” Suffredini said in an interview during the NewSpace 2016 conference in Seattle. “That will help us transition from research and manufacturing and everything else done on ISS on a future platform.”

The two companies, while having similar goals, have different approaches. Bigelow is developing its own modules at its Las Vegas factory, with plans to eventually develop modules far larger than the B330. The company is funded by Robert Bigelow, who in the company’s early days pledged to invest $500 million into the venture.

Axiom Space, by contrast, plans to have another company develop its module. Suffredini said he hopes to have that company under contract by January. That schedule is contingent on Axiom’s ability to raise money, which Suffredini said this summer was in progress.

Could the two work together, perhaps by Bigelow building an expandable module for Axiom? Suffredini sounded skeptical. “In order to make money, we have to get to orbit fast,” he said, citing a goal of having the module on the ISS by 2021. “I think it’s going to take a while to build a spacecraft out of inflatable technology.”

There’s at least one other venture interested in installing a commercial module on the ISS, which is taking advantage of a different NASA program. On Aug. 9, NASA awarded contract for the second phase of its Next Space Technologies for Exploration Partnerships (NextSTEP) program, designed to develop technologies intended to support habitats for missions in cislunar space. Several companies that won contracts in the first round of NextSTEP received follow-on contracts, including Bigelow Aerospace, which proposed installing a module on the ISS.

An industry team called Ixion is studying converting a Centaur upper stage into a module that can be added to the International Space Station. Credit: Nanoracks

An industry team called Ixion is studying converting a Centaur upper stage into a module that can be added to the International Space Station. Credit: Nanoracks

A new entrant in NextSTEP, though, was a group of companies collectively known as Ixion, which includes NanoRacks, Space Systems Loral and United Launch Alliance. They proposed converting a Centaur upper stage into a commercial ISS module (and, later, a cislunar habitat.) That approach that would save money since it would not require a dedicated launch, outfitting the Centaur after it’s used to send a cargo spacecraft to the ISS.

“Our plan is to dramatically lower the proposed costs for habitats to allow for the largest customer base, both commercial and government,” said Jeff Manber, chief executive of NanoRacks, a company current involved in commercial ISS activities through smallsat launches and other research. NanoRacks has also proposed the development of a commercial airlock that could be added to the ISS and, once the station is retired, moved to a commercial station.

How NASA leverages this growing interest in commercial ISS modules remains to be seen, and will likely depend on the responses it received from the RFI. In one sense, there is no rush for NASA to figure out how to give access to that ISS docking port: it won’t be available until 2018, when BEAM completes its planned two-year stay there, and it’s unlikely any company would have a module ready before 2020.

On the other hand, the long-term schedule for the companies has little margin. If a company gets its module there in 2020, it will have only a few years to show it can close the business case on a full-fledged commercial space station, and start getting that station in place, if NASA goes ahead with plans to retire the station in the mid-2020s. In that sense, there’s no time to lose.