Mars is about to get its first internal checkup. The InSight lander, set to launch at 7:05 a.m. EDT on May 5 from Vandenberg Air Force Base in California, will probe the Red Planet’s innards by tracking seismic waves and taking its temperature.

Finding out what Mars’ interior is like could help scientists learn how the Red Planet formed 4.5 billion years ago, and how other rocky planets, including Earth, might have formed too. “It’s going to fill in some really big holes in our understanding of the universe,” says principal investigator Bruce Banerdt, a geophysicist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

Mars is the perfect planet for this project: It’s large enough to be geologically interesting and, like the Earth, has a core and mantle beneath its crust. But the Red Planet isn’t so large and geologically active that its crust is constantly changing and erasing evidence of what it was like in the past.

“It’s kind of the Goldilocks planet,” Banerdt says.

To read more, click here.