The Empire wasn't very good at building Death Stars. The first was taken out by a couple of missiles to an exhaust port, the second due in part to an assault from a group of knee-high teddy bears.
NASA has a much better idea of how to build a planet-destroying super station: use an asteroid.
Brian Muirhead, chief engineer at NASA’s Jet Propulsion Laboratory, told Wired that a floating lump of space rock would provide all the essentials needed to build a moon-sized terror. "It could provide the metals; You have organic compounds, you have water—all the building blocks you would need to build your family Death Star."
While NASA isn't planning on building its own Death Star any time soon (the costs would be astronom... too big) Murihead is part of a team looking to land on an asteroid, rip off a chunk and then put it in orbit around the Moon to allow astronauts to collect samples. Titled the Asteroid Redirect Mission, you can read more about it here.
Here's Muirhead speaking of NASA's own Death Star ideas, giving you yet another excuse to get excited about The Force Awakens.
Just don't leave any exposed ventilation shafts, okay?