Elon Musk presented his plan for how mankind can travel to Mars and colonize the nearby planet, but he also has an idea for how we can easily zip about the entire solar system — we’re just going to need to stop to refuel along the way.

The SpaceX head honcho spoke on Tuesday at the International Astronautical Congress in Guadalajara, Mexico, where he detailed his Red Planet plans. After the bulk of the scheduled remarks were over, he briefly addressed what’s “beyond Mars.”

The key to making longer journeys within the solar system, Musk said, was the design of SpaceX’s Interplanetary Transport System. He joked that he normally doesn’t like calling anything a system “because everything’s a system including your dog,” but SpaceX’s design is special.

“It’s actually more than a vehicle,” he said, explaining that ITS really consists of a rocket booster, a spaceship, a tanker, and a propellant plant.

“Once you have all of those four elements, you can actually go anywhere in the solar system by planet hopping or moon hopping,” he said. “So by establishing a propellant depot in the asteroid belt or on one of the moons of Jupiter you can make flights from mars to Jupiter no problem.”

Musk suggested Jupiter’s moon Europa as a possible option for a propellant depot site, along with Saturn’s moons Titan and Enceladus, and much farther out there, Pluto.

Having ready-built pitstop sites, Musk said, “gives you freedom to go anywhere you want in the greater solar system,” though he added he “wouldn’t recommend for interstellar journeys.”

Musk didn’t go too in-depth about all the details of these propellant depots. We’ve got to get to Mars first, after all.