These are the vast plains of Katwijk. That’s not the name of a new Martian valley or a hidden lunar crater, though but... a beach, right here on Earth in the Netherlands. In fact, it’s where the European Space Agency is putting a new breed of robotic rovers through their paces.

Much like autonomous cars here on Earth, rovers use complex software to control their own movement, at least some of time. And this is where the European Space Agency tests the new algorithms that will be used to navigate on alien planets. Martin Azkarate, from the ESA Planetary Robotics Laboratory, explains:

“Both software routines rely on the presence of landmark features. The problem is that this flat, sandy North Sea beach doesn’t normally have any. So we added 212 cardboard ‘rocks’ for our testbed rover to navigate around.”

Yep, the otherworldliness of the image is because those aren’t real rocks at all. In fact, they’ve already been removed from the beach, which would make navigation much harder now. That’s because the two software systems used their presence to find the rover’s way—one using image recognition to compare a live view to satellite images, the other using lidar to track the vehicle’s movements.