The Trump administration wants to end direct NASA funding for the International Space Station by 2025 — but that doesn’t necessarily mean the US will stop sending people into orbit around Earth by then. Instead, NASA hopes to transition the domain of lower Earth orbit, where the space station resides, to the commercial space industry over the next seven years. But what would it take for private space companies to take over this area of space — and what exactly would they do up there?

An option would be for one or more companies to take over full-time management of the International Space Station (ISS). But the orbiting lab is expensive to fly: NASA spends between $3 billion and $4 billion each year to keep the station afloat, and that’s money that most commercial companies either don’t have or aren’t willing to spend. Multiple astronauts and flight controllers also have to work around the clock to keep the ISS running at all times, and the private sector may not have the personnel or the resources to take on such a daunting task.

commercial companies could at some point operate a cache of private space stations in lower Earth orbit

A more likely scenario is that commercial companies could at some point operate a cache of private space stations in lower Earth orbit. Such vehicles would likely be smaller, less expensive, and less complex than the ISS, but they would allow continued access to this key area of space. Lower Earth orbit is a great testing ground for the technologies needed for missions to the Moon and Mars, which NASA has its eye on. With private stations, NASA could buy time and space on these modules to continue doing tests in microgravity. Private space stations could also be used to create entirely new types of revenue, serving as places to do in-space manufacturing of satellites or platforms for tourists to visit.

The main unknown is whether or not the commercial space industry will be ready to take up this mantle by 2025. A few companies are working on habitats and technologies that could do the trick, but no one has demonstrated a standalone private station yet. And if the ISS goes out of commission before commercial companies are prepared to step in, the US could see a gap in access to lower Earth orbit.

“You wouldn’t sell your house and pack all your clothing and then have nowhere to go,” Robert Bigelow, founder and CEO of space habitat company Bigelow Aerospace, tells The Verge. “The idea of the government abandoning [the] station with no place to go is just insane.”

The administration is at least thinking about this problem. The president’s budget request, published this week, allocated $150 million to NASA to help transition the ISS to the private sector. In fact, the request calls for a total of $900 million over the next five years to help make this shift happen. But NASA doesn’t have a roadmap for how to use the money just yet. “In simplest terms, it will take a plan — a solid transition plan that doesn’t happen overnight,” Eric Stallmer, president of the Commercial Spaceflight Federation, a nonprofit aimed at promoting commercial spaceflight development, tells The Verge. “And the discussion on this transition plan needs to begin immediately.”

It’s not really clear what the end goal for the ISS would be. A recent internal NASA document, obtained by The Washington Post, proposed that companies “could continue to operate certain elements or capabilities of the ISS as part of a future commercial platform.” So maybe if the industry can’t take over the entire ISS, companies could just take over parts of it instead — perhaps breaking away modules to use on their own. That may not be feasible, though. Some of the station’s modules don’t have propulsion elements and cannot move through space without help. Plus the ISS has been designed to work as a complete system, so taking away chunks would present a significant design challenge.

“the discussion on this transition plan needs to begin immediately.”

Most experts agree it’s unlikely that NASA’s share of the ISS could be completely privatized. “Taking it over entirely is not something a normal private sector operation would do,” says Bigelow. There’s also the possibility that the US’s international partners — like the European Space Agency and Russia’s space agency, Roscosmos — will take over as well. However, NASA covers a big bulk of the station’s cost. In 2013, ESA said it had invested nearly $10 billion over the station’s lifetime, whereas NASA has invested about $87 billion on the ISS since 1993. (Russia’s total contributions are likely more than ESA, but the exact numbers are mostly unknown.) The international community would have to significantly increase their investment.

That’s why standalone private space stations may be the answer — and many companies are working toward this goal already. One prime example is Bigelow Aerospace, which specializes in inflatable space habitats. Bigelow has already demonstrated that its technology holds up in space: One of the company’s prototype habitats, called BEAM, has been successfully attached to the ISS since 2016. The company also plans to launch its next-generation standalone habitat, the B330, in 2020 or 2021. Meanwhile, other companies like NanoRacks, Axiom, and more are also trying to develop habitats that could live in lower Earth orbit.

The critical thing these companies need to show is that their vehicles can work by themselves. That means the modules will need a way to continuously supply power to the station; life support systems that will keep people alive; and their own propulsive engines that can maintain the station’s orbit so it doesn’t end up falling down on Earth. It’s possible that the $150 million allocated to NASA could be invested in these space habitat companies to accelerate the development of these systems.

If these ventures are successful, NASA will likely want access to these private stations

If these ventures are successful, NASA will likely want access to these private stations. The ISS has been a critical tool for the US space agency to test out new materials in microgravity. It’s also been a great place to learn more about how the human body adjusts to life in space — information NASA desperately needs before it sends people on long trips to the Moon or Mars. NASA could lease parts of these stations for their own astronauts. And as a result, the agency might continue to purchase crew and cargo flights from private companies like SpaceX and Boeing, which are developing these capabilities right now for the Commercial Crew Program. “It’s moving away from NASA as owner and manager to the private sector as owner and manager,” Jim Muncy, founder of PoliSpace, a space policy consulting agency, tells The Verge.

That’s attractive to commercial companies for one particular reason: making money. One concept NanoRacks envisions, for example, is a platform dedicated to manufacturing satellites in space. Right now, satellites are typically built on the ground and then launched as carefully as possible into orbit. But in the future, parts of a satellite could be sent to a station, where people — or robots — assemble the pieces into a functioning spacecraft that is then deployed into orbit at will. That way, satellites can become operational whenever they’re needed, without waiting for the perfect ride to space. “You can bring more raw materials for additive manufacturing instead of just carrying manufactured satellites,” Jeff Manber, CEO of NanoRacks, tells The Verge. “It’s a whole more sophisticated ecosystem.”

Of course, there’s always the possibility of space tourism. Bigelow has been open about the idea of turning his habitats into hotels. “What if you had a nice, plush bedroom where could see the Earth all the time. What would that be worth?” says Muncy. “That’s a market, and it’s not something the government should engage in but is appropriate for the private sector.”

But to make this privatized dream of lower Earth orbit a reality, commercial companies need to be ready, which may not happen by 2025. And there’s always Congress to consider. The idea of ending direct funding to the ISS has been met with harsh criticism from lawmakers in both parties. It seems likely that many in Congress will fight against the 2025 deadline, and the ISS could continue to receive significant funding throughout the 2020s.

Without a plan, NASA could find itself in the same scenario it’s in now with regard to launch vehicles

Yet at some point, the International Space Station program will come to an end — whether that’s in 2025 or 2035. NASA has said that the lab could feasibly last until 2028, but at that point, many of the station’s components will start approaching the end of their operational lifetimes. (Much of the technology on the ISS was built in the 1980s and ‘90s.) So it’s important to figure out a plan for the future of lower Earth orbit operations now, regardless of an arbitrary end date for ISS.

Without a plan, NASA could find itself in the same scenario it’s in now with regard to launch vehicles. When the Space Shuttle program was canceled in 2011, the agency called upon the private sector to develop spacecraft that could take the place of the spaceplane and send astronauts to and from the space station. But it’s 2018, and neither SpaceX nor Boeing are ready to send people to the ISS yet, and NASA has had to rely on Russia to launch astronauts to lower Earth orbit. NASA has the opportunity to learn from that decision and ensure that there is a viable alternative to the ISS before the station goes offline. Otherwise, we could lose a valuable place to do science in microgravity.

“The ISS is mortal,” says Manber. “It will have an end of life. The question is when and how do we begin moving away.”