As NASA works toward sending people into deep space, the agency is looking for new types of space habitats that astronauts can live in far from Earth. One company, Nanoracks, has a design idea in mind — but rather than build something completely new, the company has a bold plan to recycle space hardware to create living quarters. Their plan: turn used rocket tanks into suitable places for deep-space explorers to live.

And now, Nanoracks has signed a contract with NASA to start turning this habitat concept into reality. Last summer, the company was one of six picked to be part of the second round of NASA’s NextSTEP program, an initiative to create concepts and ground prototypes of novel deep-space habitats. Now with a finalized contract, Nanoracks can get to work on developing its concept, called Ixion, and eventually turning a spent rocket tank into a habitat that can then be tested out in space.

The company wants to utilize hardware that would otherwise go to waste

Basically, the company just wants to utilize hardware that would otherwise go to waste. When a satellite launches on top of a rocket, the probe is typically delivered into its final orbit by the vehicle’s upper stage — the top section of the rocket that contains its own separate engine(s) and fuel. That means the upper stage usually orbits along with the satellite after it’s been deployed from the rocket. By the time it’s in orbit, most of propellant in the stage’s tank has been depleted, which creates a whole lot of empty space that is going unused.

If these stages go to a low enough orbit, they’re usually deorbited on purpose; any remaining propellant is used to redirect the stage toward Earth and have it burn up in the atmosphere. That way they don’t add to the growing amount of space debris already around Earth. But instead of getting rid of these stages, Nanoracks wants to keep them in orbit and then refurbish them, turning them into something completely new. “We’re augmenting what already exists,” Mike Johnson, chief designer at NanoRacks, tells The Verge. “You kind of double down for your money.”

The plan would be to vent the rest of the propellant out into space, making the tank completely empty. Or if the rocket uses cryogenic propellants, as many modern vehicles do, then the materials will boil off after a few days as the stage orbits Earth and is heated up by the Sun. Once the tank is completely empty, Nanoracks will fill it with pressurized air from smaller vessels attached to the outside. In fact, each of these tanks-turned-habitats will have smaller modules attached to the outside, containing vital supplies like life support systems and cargo that can be used to make the tank a viable place to live. The modules can also be used to attach the stage to other habitats already in space.

After the tank is pressurized, then it’s time to send in a crew — either humans or robots — to outfit the inside. Most propellant tanks are equipped with small hatches, and the company plans to add docking tunnels to these hatches to allow crews to get inside the tanks. They’ll then bring in foldable fabrics to make the interior a little more astronaut-friendly and comfier than just an empty metal structure. “The outfitting equipment is pretty lightweight; it’s made out of fabric and built in wiring,” says Johnson. “Compared to other ways of creating habitable space, it’s really a cheap way to do it — in terms of cheap in mass, cheap in cost, and cheap volume.”

“Compared to other ways of creating habitable space, it’s really a cheap way to do it.”

It’ll be a while before such habitats are open for new tenants though. For now, Nanoracks is focused on developing the concept further and creating a prototype on the ground. After that, the team will try to refurbish a tank within one of the upper stages made by the United Launch Alliance, called Centaur. This stage is currently used on the Atlas V rocket and will soon be used on the company’s next vehicle called Vulcan. They then hope to attach this refurbished tank to the International Space Station for testing. And if all goes well, the tank may just stay there. “A secondary objective is that we could leave it there and potentially create a commercial space station module on the ISS,” says Johnson.

Nanoracks is aiming to get the tank habitat to the ISS in the next four years or so, says Johnson. But for now, the company is focused on this first contract with NASA, which involves doing a study on the concept’s feasibility. Out of all the other companies in the NextSTEP program, Nanoracks is the only company that plans to outfit used tanks, and Johnson hopes that will give them a lot of flexibility moving forward. “Anything that uses an upper stage could use this concept,” he says. “It really fits in everywhere.”