We already know that building a Star Wars–style Death Star from scratch would be an expensive endeavor (a group of economics students from Lehigh University calculated that it would cost $852 quadrillion, or roughly 13,000 times the global GDP). But according to one NASA engineer, using materials that are already in space would be a much more practical way to go.

Brian Muirhead is the chief engineer at NASA’s Jet Propulsion Laboratory, and he’s been a Star Wars fan since its release in 1977. He recently told WIRED that the best way to build a Death Star would be to construct it out of an existing asteroid. “It could provide the metals,” Muirhead said. “You have organic compounds, you have water—all the building blocks you would need to build your family Death Star.”

He’s currently working on a different project with NASA involving asteroids, only their end goal is much less diabolical than the Galactic Empire’s. As part of their Asteroid Redirect Mission, NASA is planning to use unmanned spacecraft to collect boulders from the surface of an asteroid and place them in the Moon’s orbit to be studied and sampled later on. The mission is scheduled to launch in 2020—or to put that another way, at least five Star Wars films from now.

[h/t: WIRED]