The spacecraft will take six years to reach a metal-rich asteroid that could have been formed from the remains of an early planet’s core.

The probe took off from the Kennedy Space Center in Florida inside the cargo bay of a SpaceX Falcon Heavy rocket. Its journey has been estimated to be 2.2 billion miles long (3.5 billion km), taking approximately six years. 

The mission is expected to provide scientists with clues of the Earth’s formation. 

“It’s long been humanity’s dream to go to the metal core of our Earth. I mean, ask [author] Jules Verne,” said lead scientist Lindy Elkins-Tanton, Arizona State University. “The pressure is too high. The temperature is too high. The technology is impossible. But there’s one way in our solar system that we can look at a metal core and that is by going to this asteroid.”

There have been previous missions to asteroids, but these have all focused on rocky or icy formations instead of metal ones such as Psyche, which...