Explainer: Japan lands rovers on asteroid surface

By Elton Gomes 

The Japan Aerospace Exploration Agency (JAXA) said on Saturday that it has successfully landed a pair of rovers on an asteroid named Ryugu. The landing of both rovers marks the world’s first moving, robotic observation of an asteroid’s surface.

The rovers are collectively known as MINERVA-II1. The Japanese space agency has confirmed that MINERVA-II1 is the world’s first mobile exploration robot to land on an asteroid’s surface. “I felt awed by what we had achieved in Japan. This is just a real charm of deep space exploration,” Takashi Kubota, a spokesperson for JAXA, said, CNN reported.

After both rovers separated from the Hayabusa2 spacecraft and landed on the asteroid Ryugu, a statement from JAXA confirmed that both rovers are in good condition and have begun transmitting images and data.

Japan created history as it became the first country in the world to successfully land two robotic rovers on an asteroid. The Hayabusa2 probe was launched in December 2014, and it arrived at the asteroid 162173 Ryugu in June. The spacecraft began its descent on Thursday morning while preparing to eject its two rovers.

Weighing only 3.3 kg, the MINERVA-II1 is a compact rover and consists of two more rovers – Rover-1A and Rover-1B. On September 21, the MINERVA-II1 rovers separated from the Hayabusa2 spacecraft.

What will the rovers do on the asteroid surface?

Low gravity on asteroids will allow these robotic rovers to jump to as high as 49 feet and even stay in the air for as long as 15 minutes to study the physical features of the asteroid. Weighing around a kilo each, the rovers are equipped with wide-angle and stereo cameras. In addition, they can measure the surface temperature of the asteroid using spine-like projections from the edges of their hoppers. The rovers’ motor-powered internal rotors will allow them to propel across the asteroid’s surface.

Future plans

Next month, the spacecraft Hayabusa2 plans to shoot a two-kilo copper object to blast a small crater on Ryugu’s surface. Once the crater will be created, the probe plans to collect “fresh” materials that have not yet been exposed to millions of years of wind and radiation. Hayabusa2 will then collect samples from the crater, which will later be sent to Earth for laboratory studies. A third rover named MASCOT will also be launched from the Hayabusa2 in early October.

Japanese rover becomes first to land on asteroid surface

Ryugu is a blackish coloured, diamond-shaped asteroid, and it rotates on its axis once every 7.5 hours. The asteroid’s surface is known to be rougher than expected, as it has several boulders and barely any smooth places. Though the European Space Agency managed to land on an icy comet previously, it has been confirmed that the MINERVA-II1 is the world’s first rover to land on the surface of an asteroid. For the first time, autonomous movement and picture capture will be possible on an asteroid’s surface. MINERVA-II1 is, therefore ‘the world’s first man-made object to explore movement on an asteroid surface’.

How can studying asteroids help solar system science?

Beneath their surfaces, asteroids are known to contain important information about the formation of the solar system billions of years ago.

Asteroid Ryugu, the 1 kilometre-wide space rock, is expected to be “rich in water and organic materials,” thus scientists will be able to “clarify interactions between the building blocks of Earth and the evolution of its oceans and life, thereby developing solar system science,” JAXA said in a statement, CNN reported.


Elton Gomes is a staff writer at Qrius

Asteroid