NASA has flown the International Space Station for the last 15 years, and during that time it has offered private industry a pretty sweet deal. The space agency pays transportation costs to and from the station for experiments and provides astronaut time to tend to that research. And when NASA needed new spacecraft to get its astronauts on board the station, it paid private companies to develop their own vehicles for that purpose. NASA, in some sense, has become the Chamber of Commerce for outer space.

But all good things must come to an end, so the free ride in low Earth orbit for private industry may stop as soon as a decade from now. “We’re going to get out of ISS as quickly as we can,” said William Gerstenmaier, NASA’s chief of human spaceflight, last week. “Whether it gets filled in by the private sector or not, NASA’s vision is we’re trying to move out.”

Gerstenmaier made those comments during a meeting of NASA’s advisory council in early December at Johnson Space Center, which Ars attended. The comments are striking because, while the remarks reflect NASA’s desire to see US commercial industries thrive in the space around Earth, it is not the agency’s top priority to ensure that happens. Gerstenmaier said NASA is committed to moving humans deeper into space to the vicinity of the Moon, an area known as cislunar space.

Although he’s not a high-profile figure outside of the space industry, Gerstenmaier is arguably the most influential person when it comes to US spaceflight. He is presently weighing how long NASA can afford to fly the International Space Station before moving beyond low-Earth orbit.

The program’s budget, now about $3 billion annually, is projected to rise to about $4 billion by 2020. NASA cannot afford both a robust space station program and active human exploration program in cislunar space, he said.

His comments come as a debate rages inside and outside of NASA about what happens in low-Earth orbit in 2024, or 2028 at the latest, when the space agency stops supporting the space station. The most likely outcome is that the station will be safely deorbited, break apart in the atmosphere, and fall into the Pacific Ocean. And then what?

NASA says it would like to see the private space industry “take over” low-Earth orbit, although it acknowledges that any successor space station or orbiting module will be far smaller than the $140 billion space station, a collaboration between 15 countries. The message from NASA to the US industry is simple: we’re serious about the commercialization of low-Earth orbit, we have this marvelous facility available with unique capabilities, and we want you to use the heck out of it.

No one really knows what innovations may come from working in microgravity. Financially, does it make sense to fabricate delicate nanostructures or grow protein crystals there? Other opportunities for commercial development include space tourism, industry, and marketing. Some of these ideas will work, and some will fail. Companies should find out now by experimenting on the station while it exists, NASA officials say, and while the space agency is paying for most of the costs.

NASA Administrator Charles Bolden has met with US Commerce Department officials about potential tax incentives for microgravity research, and Gerstenmaier said he believes there is a “huge potential” for US industry in low-Earth orbit. He cited technologies like the Internet and GPS satellites as innovations that were not foreseen but sprang up as businesses took advantage of new horizons. “We really want to open up low-Earth orbit to the terrestrial markets, and I want the private sector to explore,” he said.

Until now the most successful ventures in low-Earth orbit have focused on information, with remote-sensing satellites and communications satellites transferring data. It’s not clear whether those technologies, or other industries in space, will evolve enough that they can support a sustained or even infrequent human presence in orbit absent a major government-backed facility.

It’s also uncertain, from a public policy standpoint, whether NASA will be allowed to abandon low-Earth orbit without a viable commercial presence in its wake. By the early 2020s China’s space agency has said it will have a permanently inhabited space station there, and it has invited NASA’s European partners to join it.

But NASA, Gerstenmaier warned, must move on at some point if it is ever to go deeper into space. Humans haven’t left the cocoon of Earth’s gravity well since 1972, when Apollo 17 returned to Earth. Although there are questions about the viability of the agency’s goal to send humans to Mars, it has begun to develop the tools to send astronauts back into cislunar space in the late 2020s. To afford this, however, NASA needs to get the space station costs off its books.

During the advisory council meeting, in response to questions, Gerstenmaier also made it clear that NASA didn’t require a vibrant commercial presence in low-Earth orbit as a staging point for missions deeper into space. “We gave industry a 10-year horizon,” he said, adding he’s not sure industry will be ready to commercialize low-Earth orbit. “The chances of this are low, but it’s worth a try.”