The Japan Aerospace Exploration Agency (JAXA) delivered this Autumn a world-first in space exploration with their Hayabusa-2 (Japanese for “Peregrine Falcon-2”) probe – the first images from the surface of an asteroid.
Carrying various small rovers and other scientific instruments, it completed its rendezvous on the 1-kilometre wide asteroid Ryugu on the 27th June this year, and is still surveying the asteroid at the time of writing.
The first rover aboard Hayabusa-2, Rover-1A, successfully landed on the asteroid on 21st September, capturing breathtaking photographs such as below from the surface of Ryugu:
This dynamic photo was captured by Rover-1A on September 22 at around 11:44 JST. It was taken on Ryugu’s surface during a hop. The left-half is the surface of Ryugu, while the white region on the right is due to sunlight. (Hayabusa2 Project) pic.twitter.com/IQLsFd4gJu
— HAYABUSA2@JAXA (@haya2e_jaxa) 22 September 2018
Besides camera technology, Rover-1A and its counterpart, Rover-2B, contain thermometers for temperature reading, solar cells combined with capacitors for electrical power deep in space and a very unique means of navigating the asteroid. Internal masses are spun within the rovers, allowing them to “hop” across the surface due to the very low gravity present on Ryugu (due to its minuscule size compared to much larger objects like Earth).
As Hayabusa2 descended towards Ryugu to deploy the MINERVA-II1 rovers, the ONC-T camera snapped the highest resolution image yet of the asteroid surface!https://t.co/JDbk29RXHG pic.twitter.com/KFsLet5BMJ
— HAYABUSA2@JAXA (@haya2e_jaxa) 28 September 2018
The image embedded within the tweet above, taken by the ONC-T camera aboard the main Hayabusa-2 probe a day before the previous image, shows a bird’s (or rather, a Falcon’s) eye view of Ryugu’s surface from an altitude of about 64 metres. With a 1-metre scale included in the photograph, a new perspective can be applied to the asteroid. Its similarity to rock formations on Earth stand in stark contrast to the surface image which reveals an otherworldly sky, devoid of atmosphere and dominated by the Sun and the empty expanse of space.
A couple of weeks later, Hayabusa-2’s MASCOT (Mobile Asteroid Surface Scout) rover also landed on Ryugu at its landing site, “Alice’s Wonderland”. Developed by German and French scientists in collaboration with the Japanese, it landed on 3rd October and contained various scientific instruments. These included a magnetometer, radiometer, infrared spectrometer and a camera which took the photo embedded within the tweet below between 10 and 20 metres from Ryugu’s surface, allowing for a clearer view of Ryugu without the lens flares present in the first photo taken by Rover-1A, which distorted the image.
So glad to finally be home, at asteroid #Ryugu! Here’s another picture that I took while I was landing – between 10 and 20 metres from the surface! What a place! It’s out of this world, don’t you think? #AsteroidLanding #hayabusa2 pic.twitter.com/PAxaQ3AwHX
— MASCOT Lander (@MASCOT2018) 7 October 2018
MASCOT’s exploration of Ryugu was a short one, though. Due to the shoebox-sized hopping robot’s dependence on non-rechargeable lithium-ion batteries, MASCOT ceased explorations after 17 hours.
Hayabusa-2 is expected to leave Ryugu in December 2019, with a return to Earth in the same month in 2020, bringing samples of Ryugu for scientific study. Meanwhile, on 3rd December NASA successfully landed their own spacecraft on an asteroid. Within a week of NASA’s OSIRIS-Rex landing on the asteroid of Bennu, the craft had discovered water bound up within clay minerals on the asteroid’s surface.
After Mars and the Moon, the asteroids of our solar system may be a likely target for future human exploration and colonisation. Ryugu alone is believed to contain a variety of useful minerals and metals that could in future be mined and either sent back to Earth or used by human explorers, scientists and colonists. These include nickel, iron, cobalt and essential elements for human survival beyond Earth such as nitrogen, hydrogen and water.