About a month ago, NASA quietly released a congressionally mandated report re-thinking the agency's approach to human spaceflight in low-Earth orbit, or LEO. NASA is currently the primary sponsor of the International Space Station, shelling out between $3 to $4 billion each year for operations and transportation costs. The White House and NASA want to change that, envisioning NASA as just one of many participants in a thriving economy where humans live, work, and play in LEO.

Essentially, NASA can't afford to operate the ISS while also working to establish a presence on and around the Moon. The White House's most recent NASA budget request proposes to "end direct U.S. financial support for the International Space Station (ISS) in 2025, after which NASA would rely on commercial partners for its LEO research and technology demonstration requirements."

What savings this will generate, and whether they will be enough to significantly increase human activity beyond LEO, isn't clear. This is just the first step of a larger, pending debate.

The report is officially called the International Space Station Transition Report, and it's a bit of a slog to read. There are dense passages re-hashing the same point multiple times, and a liberal use of passive voice. NASA never does something—it is proposing. The report doesn't actually say what's going to happen; it lays out a set of "transition principles," promising to define a full strategy later. This transition/strategy delineation, along with the waffly grammar, doesn't exactly fill you with confidence that things are going to smoothly.

The transition principles are ambitious: NASA wants to create a new humans-in-LEO market, and then become the non-primary customer for that new market. The market must meet a laundry list of extensive requirements set by NASA and other federal users. It must be profitable for private companies, but cost NASA less than what it currently takes to run the ISS.

Oh, and all of this must be in place by 2025—less than seven years from now. Can NASA pull that off without yielding on cost, schedule, or both?

If you prefer your space takes in audio form, don't miss the most recent Planetary Radio Space Policy Edition podcast, which tackles the same subject!

The general plan

NASA is considering two options when it comes to transitioning away from its current space station model.

Option 1: A private company takes over U.S. ISS operations

Before the end of fiscal year 2018, NASA will collect ideas from companies interested in taking over ISS operations, according to the transition report. It's unclear exactly which station components this would encompass.

I asked two people with experience working on the ISS program to weigh in on this idea (neither were not authorized to speak on the record, so I have withheld their identities). One person pointed out that private companies like Boeing, Stinger Ghaffarian Technologies, and historically, United Space Alliance, already provide ISS operations support. Privately employed flight controllers work alongside their NASA counterparts. Therefore, the biggest transitional challenge might be paperwork-related.

"What I could see being a problem are the procedures and flight rules and other documents used on console that were developed under certain contracts along with NASA—what happens to them?" the person said. "That I don't know."

But would such a switch save any money?

"I won't say it can't be done," another person told me. "The question is—what do you scale back? Something has to scale back or you have to fundamentally change the concept of how the ISS operates."

Out of the $3 to $4 billion spent on the ISS each year, more than half of that is due to transportation costs—and that's unlikely to change. In fact, a recent report by NASA's Office of Inspector General showed transportation costs are actually rising.

Of the $1.5 billion spent on actual ISS operations, where can a private company recoup costs? Shedding any ISS capability inevitably comes with trade-offs. One example: NASA keeps spare ISS parts both in space and on the ground, and employs experts who diagnose things that break (NASA also sends broken components back to Earth). That's expensive, so perhaps a private company could do without that practice. But what happens the next time something goes belly-up?

For facilities, would a company build its own control center, or use existing ones in Houston, Huntsville, Tokyo, Montreal, and Munich? What about astronaut training facilities? Maybe a private company could do without spacewalks. But that might not save NASA much money; the agency still needs to retain its spacewalking capabilities and training facilities for future deep space missions.

For the sake of argument, let's imagine that a private company could shave 30 percent off of annual ISS operations costs—a cost savings of $450 million per year. But is that really enough for NASA to get to the Moon?

Option 2: A private company sets up a new station

Though a private company could construct an entirely new, standalone station, a more likely scenario is a company building the core of such a station at the ISS. There, private modules could be test-driven, and NASA and the company can work out operational bugs. In 2025, the company could detach the modules and use them to form a new station, possibly with some existing ISS modules. All of the station's modules are certified to last through 2028, and some may last even longer—though components inside those modules are certainly expected to break.

There are multiple options for adding new modules to the station. An example of how this would work is the Bigelow Expandable Activity Module, or BEAM, a testbed module that was added to the station in 2016. But NASA has been stalled on the question of how to handle future BEAM-like activities since then, even after issuing an information request for companies wanting to use ISS ports. The transition report says "the agency has been assessing the policy, programmatic, and technical impacts of implementing a commercial module on the ISS."

Will NASA make a decision soon? In reporting on private space stations in the past, I've spoken with two companies—Axiom Space and Bigelow Aerospace—who are very interested in developing ISS-ready modules. Both have implied they're ready to fly, if NASA would just give them the opportunity.

The requirements

No matter what a new space station in LEO actually looks like, NASA has a laundry list of things it must be able to do:

Host current, and possibly new, international partners

Host NASA astronauts for short and long-term crewed expeditions

Accommodate new life support and environmental monitoring systems for real-world, long-duration tests

Serve as a research laboratory for NASA, the National Science Foundation, the Department of Defense, and the National Institutes of Health

Host research including, but not limited to: plant, microbial, animal, and human biology, fundamental physics, cryogenics and heat transfer, combustion, materials science, medicine, manufacturing, biomedical and communications demonstrations

Host astrophysics, space science and Earth science experiments (this would seem to mean exterior-mounted experiments)

That's a lot of requirements! Keep in mind this list doesn't cover the needs of any other customer besides NASA—and that NASA isn't even supposed to be the primary customer.

The market

While NASA is good at spaceflight, it's not as sure-footed when it comes to business—especially when being tasked to create an entirely new commercial market (has NASA ever been directly tasked with doing so?). The agency's commercial cargo and crew programs were successful, but they didn't really create new markets; rather, they serve the existing ISS transportation market. SpaceX leveraged its dominance in that market to capture a large share of another existing market: launches.

The report gets a little existential about NASA's new market-creation role, listing this premise as one of the "challenges" to commercializing LEO: "Government acceptance of the premise that commerce has value."

That's a loaded, ideological premise! Value for whom? NASA? Taxpayers? Businesses? The report doesn't say, but to keep it simple, let's look at commerce as value for NASA and taxpayers. That value would presumably come in the form of lower costs and increased capabilities.

Cost is, by far, the biggest question mark. To what degree will NASA subsidize this new market, while still reducing the agency's overall LEO funding burden? That will depend on how profitable a private space station is.

The only company to have flown private space station hardware, Bigelow, is unsure enough about profits that they're currently conducting a large-scale study on the topic:

"This subject has had ambiguity for many years," the company's operational arm said in a February press release. "BSO [Bigelow Space Operations] will be spending millions of dollars this year to establish concrete answers."

Existing studies have been wildly incongruent, betraying the market uncertainty of private space stations. Axiom Space sponsored a report that found a potential market of about $4 billion annually by the time the ISS retires in 2025. But a 2017 study conducted by the Office of Science and Technology Policy, cited in the ISS transition report, found late 2020s revenues ranging between just $455 million and $1.2 billion per year. That same report estimates costs between $463 million and $2.3 billion. These estimates also assume very rosy scenarios for launch costs, where human and cargo costs are approximately 75 percent less than current prices.

The implication? There are far more scenarios than not in which a private space station is a losing business idea.

"Venture capitalists interviewed for the project noted that the projections of revenues and costs are so uncertain that they would have little interest in financing a space station until projected revenues show signs of actually materializing," the report said.

The takeaway

In theory, NASA won't have to figure all this out on its own. The report mentions a working group consisting of NASA, the Department of Transportation, the Department of Commerce, and others. This working group will ostensibly come up with policy recommendations to help enable the humans-in-LEO market.

That's a good start, but it relies on the premise that a few regulatory tweaks are all that's needed to grow the small amount of commercial activity currently taking place aboard the ISS into a blossoming new commercial market. NASA only has one chance to get this right. A botched transition could destabilize the human spaceflight program as it focuses on returning to the Moon for the first time in half a century.

Casey Dreier contributed to this story.