NASA has been part of the International Space Station for the last 15 years, but now it's slowly spreading its wings, making it known that it is letting go of the facility to pursue its goals of flying beyond low-Earth orbit.

In an advisory council meeting early December, William Gerstenmaier, NASA human spaceflight chief, said that the agency is making the move to get out of the ISS as quickly as possible, regardless of whether or not its absence is filled by the private sector. This statement is striking because while NASA is clear about its desire to see commercial industries in the U.S. thrive in space, it is not keen on making sure that happens. Instead, NASA is committed towards bringing humans closer to the moon, in an area called cislunar space.

This decision to drop involvement in the ISS is mostly a cost-cutting move. Right now, NASA has a budget of around $3 billion every year. By 2020, this figure is expected to reach around $4 billion. Given the high costs of space exploration, the agency will not be able to afford keeping both a space station program and one for human exploration in cislunar space.

Gerstenmaier's statement comes at a time when there is a debate about what would be the fate of activity in low-Earth orbit once NASA breaks away from the ISS. One of the likeliest results is that the space station will be deorbited safely, breaking apart as it enters the Earth's atmosphere before falling into the Pacific Ocean.

Aside from research possibilities, the ISS also offers commercial opportunities like space tourism, to continue funding its operation.

"We really want to open up low-Earth orbit to the terrestrial markets, and I want the private sector to explore," said Gerstenmaier.

There remains uncertainty, but he made it clear that NASA must at some point move on if the U.S. ever wants to make it into deep space. No one is sure if going to Mars is viable, but the agency has started developing tools to be able to send astronauts to cislunar space at least towards the end of 2020. The effort will be costly, however, once again opening up the practicality of dropping ISS involvement to reallocate funding.