Astronomers detail the jarring journey of the MASCOT lander to the surface of an asteroid.

A small lander bounced repeatedly across the terrain of its target asteroid before finally coming to a rest.

Japan’s Hayabusa2 mission launched in 2014 with the goal of analysing near-Earth asteroid Ryugu. After reaching the asteroid, the spacecraft released the MASCOT lander in 2018 and captured its descent on camera.

Frank Scholten at the Institute of Planetary Research at the German Aerospace Center in Berlin and his collaborators analysed these images to reconstruct the path of the boxy, 9.8-kilogram lander. The distance between the lander and its shadow, as well as information from instruments on the lander itself, showed that, during its 17-minute journey from the mothership to a complete stop, MASCOT reached a speed of 0.6 kilometres per hour. It bounced 4 times before coming to a rest on the asteroid’s surface, where it gathered data for 17 hours before its non-rechargeable battery ran out of juice.

Tracing the descent will help the researchers to put the images captured by the lander into context, and the springiness of the asteroid’s surface could reveal important information about the rocky body’s make-up.