In April last year, a Japanese spacecraft launched a strike from above on an asteroid.

Japan’s space agency was not declaring war. The bombardment was part of the work of Hayabusa2, a robotic space probe that is gathering hints about the origins of the solar system by studying the rocky object, Ryugu. It is a type of asteroid that is full of carbon molecules known as organics, including possibly amino acids, the building blocks of proteins.

The mission also provides information that could help defend our planet in the future. Ryugu, a diamond-shaped body more than half a mile wide, is among the asteroids that swing inside the orbit of Earth as they travel around the sun. Ryugu itself is not expected to collide with our planet anytime soon, but other similar asteroids might.

In the April experiment, the spacecraft released an apparatus, the Small Carry-on Impactor, and scurried to a safe location behind the asteroid. Plastic explosives accelerated a four-pound copper projectile to 4,500 miles per hour into its surface. A camera deployed by Hayabusa2 recorded the impact.