It’s reassuring to know that our planetary defense systems are on point.

The European Space Agency shared that on July 6, their automated systems, which keep an eye on the skies for potentially dangerous objects like asteroids, triggered an alert.

“The object, estimated at around 50 m [164 feet] in diameter, was spotted hurtling towards Earth on a path that would take it uncomfortably close to the moon and our planet,” ESA wrote. “But thankfully, this was no asteroid.”

As objects move through the sky against the background of stars, different observatories (like the NASA-funded Asteroid Terrestrial-impact Last Alert System) identify whether it’s a new object, and if so, if it might pose a hazard to Earth. In this case, follow-up observations determined the detected object was ESA’s Juice spacecraft, short for Jupiter Icy Moons Explorer. The probe, en route to the deeper solar system, is flying by Earth and the moon to exploit our gravity as it slingshots through space.

It turns out the Juice spacecraft isn’t nearly 50 meters across. Its solar panel wings measure 27 meters (88 feet) from tip to tip — which is still quite big for a deep space probe. But it appeared very bright, owing to its reflective solar panels, so ESA’s automated system initially estimated the object was a larger rock reflecting more light.

Scanning the skies for potentially menacing objects is essential. It gives us time to prepare, and if necessary, evacuate a certain area. “You need to know what’s coming, when it’s coming, and how hard it’s going to hit,” Eric Christensen, the director of the near-Earth object-seeking Catalina Sky Survey in Arizona