Hayabusa 2 sends third and final robot towards asteroid Ryugu

Japan's Hayabusa 2 probe has made its presence known on Ryugu since entering orbit around the asteroid in June 2018, deploying a pair of bouncing robots and touching down on its surface not once, but two times. The spacecraft has now sent in a third and final rover for a closer look, as mission control begins to think about bringing the probe and its precious samples home.

The Hayabusa 2 probe launched in 2014 on a mission to study the near-Earth asteroid Ryugu. Packed aboard was a shoebox-sized lander called the Mobile Asteroid Surface Scout (MASCOT), which touched down in October last year, along with a pair of skipping robots which were deployed a month earlier.

Those two robots, dubbed the Minerva-II1 rovers, are tasked with snapping images and gathering temperature data from the surface. A rotating motor enables them to skip across the landscape as a way of exploring the terrain, and their insights were key to perhaps the most dramatic part of the Hayabusa 2 mission.

The work of the Minerva-II1 rovers enabled mission control to pick out the best spot for the spacecraft to fire a projectile into the surface of Ryugu. This created an artificial crater, which the spacecraft then returned to a couple of months to collect dust samples.

But Hayabusa 2 isn't quite done yet. JAXA has confirmed that the Minerva-II2 rover is now on its way to the surface. Developed by a consortium of Japanese universities, this 1-kg (2-2-lb) robot packs an accelerometer, thermometers and cameras. It was deployed from the Hayabusa 2 probe at a height of around 1 km (0.62 mi) from the surface.

This separation took place successfully overnight, with the spacecraft now rising to an altitude of 20 km (12 mi). From here, it will optically observe Minerva-II2 as it drifts down towards the surface over the next seven days. These observations, combined with measurements taken by the probe, will hopefully enlighten scientists' understanding of Ryugu's gravitational field. Once on the surface, the hope is that it will continue to relay useful data.

Hayabusa 2 is set to start returning to Earth at the end of the year for arrival toward the end of 2020. Assuming its samples make it back intact, scientists will study this ancient asteroid in search of 4-billion-year-old secrets from the early solar system.

Source: JAXA (Twitter)