The tiny robots currently skipping across the surface of asteroid Ryugu have gained some company today, with mothership Hayabusa 2 successfully deploying their bigger sibling, the Mobile Asteroid Surface Scout (MASCOT). The shoebox-sized rover has touched down safely on the surface, with mission control confirming that all seems to be in working order.

JAXA's Hayabusa 2 probe was launched in 2014 with the lofty goal of of grabbing samples from the surface of Ryugu and returning them to Earth. Key to the mission's success is the set of landers taken along for the ride, starting with compact bots MINERVA-II1 Rover-1A and 1B.

These touched down on Ryugu on September 23 and are now sending back data and images via the mothership. These hexagonal robots measure just 18 cm (7 in) across and are exploring the asteroid through low-gravity hops that bounce them 15 m (49 ft) across its surface each time.

They've now been joined by the larger MASCOT lander, developed by the German Aerospace Center, which was ejected from Hayabusa 2 at an altitude of 51 m (167 ft) and left to free fall to the surface, snapping 20 images during its journey. The lander is equipped with a DLR camera, thermal systems a radiometer, an infrared spectrometer and a magnetometer and is already collecting data at its current site.

Like the smaller rovers, MASCOT will jump across the surface once its work is done at this first location. It does this with a motorized swing arm capable of launching it distances of up to 70 m (230 ft) at a time.

Along with these landers, Hayabusa 2 will also fire a 2-kg (4.4-lb) copper projectile into the surface to create an artificial crater, kicking up dust and buried material to be collected by a purpose-built grabber.

Hayabusa 2 will spend around 18 months at the asteroid before (hopefully) return to Earth with its samples in tow in 2020. Its findings could shed all kinds of light on the makeup of primitive asteroids like Ryugu, which in turn could teach us valuable lessons about the formation of our solar system.

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