Former NASA astronaut Buzz Aldrin, the second man to step foot on the moon is calling on the US to stop funding the International Space Station and instead use the billions of dollars being spent on it each year to send people to the planet Mars.

“We must retire the ISS as soon as possible,” the former Apollo 11 moonwalker said Tuesday (May 9) during a presentation at the 2017 Humans to Mars conference in Washington, D.C. “We simply cannot afford $3.5 billion a year of that cost.”

Establishing private outposts in LEO is just the first step in Aldrin’s plan for Mars colonization, which depends heavily on “cyclers” — spacecraft that move continuously between two cosmic destinations, efficiently delivering people and cargo back and forth.