You may not know it but Japan's space agency quietly made history more than 170 million miles from Earth.
On Sept. 22, JAXA (Japan Aerospace Exploration Agency) announced that its Hayabusa-2 spacecraft had successfully dispatched and landed two small Minerva-II1 rovers on the surface of a 1-kilometer-wide asteroid known as Ryugu. The first pictures sent back, while the rovers themselves were "bouncing" over the surface, are blurry, but nonetheless remarkable.
Photo taken by Rover-1B on Sept 21 at ~13:07 JST. It was captured just after separation from the spacecraft. Ryugu's surface is in the lower right. The misty top left region is due to the reflection of sunlight. 1B seems to rotate slowly after separation, minimising image blur. pic.twitter.com/P71gsC9VNI
— HAYABUSA2@JAXA (@haya2e_jaxa) September 22, 2018
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) September 22, 2018
Now that the little solar-powered rovers are safely on the asteroid, a critical milestone in the more than three-and-a-half year journey it took to reach Ryugu, they will begin exploring its surface and collecting data. Each is equipped with wide-angle and stereo cameras, as well as motor-powered internal rotors that allow them to "hop" from location to location.
Just several days after landing on the asteroid, the two rovers transmitted clearer images and a short video that shows the landscape and topography in greater detail.
Rover-1B succeeded in shooting a movie on Ryugu’s surface! The movie has 15 frames captured on September 23, 2018 from 10:34 - 11:48 JST. Enjoy ‘standing’ on the surface of this asteroid! [6/6] pic.twitter.com/57avmjvdVa
— HAYABUSA2@JAXA (@haya2e_jaxa) September 27, 2018
"The project team is fascinated by the appearance of Ryugu and morale is rising at the prospect of this challenge," project manager Yuichi Tsuda said in a recent JAXA press release. "Together with all of you, we have become the first eyewitnesses to see asteroid Ryugu. I feel this is an amazing honor as we proceed with mission operations."
Surface party to grow
What's even more remarkable about the Hayabusa-2 mission is that it's only just getting started. In fact, two more robotic spacecraft are slated to touch down on Ryugu's surface. The first, called Rover 2, will detach from Hayabusa-2 and use optical and ultraviolet LEDs to analyze lingering dust over the surface of the asteroid. The second, called MASCOT, will study the magnetic properties of Ryugu and non-invasively analyze it mineral composition.
Hello #Earth, hello @haya2kun! I promised to send you some pictures of #Ryugu so here’s a shot I took during my descent. Can you spot my shadow? #AsteroidLanding pic.twitter.com/dmcilFl5ms
— MASCOT Lander (@MASCOT2018) October 3, 2018
MASCOT successfully landed on Oct. 3 and also tweeted, "And then I found myself in a place like no place on Earth. A land full of wonder, mystery and danger! I landed on asteroid Ryugu!"
The rover's life will be short-lived though since it only has a battery life of 16 hours. But during that time, it will be busy measuring magnetic fields, determining surface temperatures and capturing images at different wavelengths.
You can see an animation of MASCOT's landing below.
The initial plan was for the Hayabusa-2 to jettison a Small Carry-on Impactor (SCI) early next year to produce a small charge on the asteroid's surface. After two weeks waiting for the dust to clear, the Hayabusa-2 would land within this newly created crater and retrieve pristine sub-surface material to return to Earth. However, the plan is now on hold after JAXA analyzed more than 200 images taken by the rovers and realized there's no smooth area large enough on the asteroid for the spacecraft to land. However, the space agency said its still hopeful that it can locate an area. If all works out, the scientifically rich samples Hayabusa-2 would collect are slated to reenter the Earth's atmosphere in December 2020.
A prelude to asteroid mining?
Scientifically, Ryugu is an attractive candidate to researchers because it's thought to contain primitive materials that could shed light not only on the origins and evolution of our own solar system, but also life in general. For the nascent asteroid mining industry, the mission also stands as an interesting case study in the retrieval and return of samples back to Earth.
According to the Asterank website, operated by mining company Planetary Resources, Ryugu's rich composition of nickel, iron, cobalt, water, nitrogen, hydrogen and ammonia make it worth $82.76 billion.
For now, however, JAXA is just interested in analyzing as much of Ryugu before the Hayabus-2 fires its ion engines and begins its return trip back to Earth in December 2019.
"Learning about asteroids is important for the future of space exploration," project manager Hitoshi Kuninaka said in an interview with Spaceflight Now. "This is a difficult mission, but in order for humans to expand from Earth into space, it will be necessary to meet challenges. We need a lot of technology and information about the solar system, and Hayabusa2 will make a big step in these areas to help us be ready to plan and collaborate in the next step of space exploration."
Editor's note: This article has been updated since it was originally published in September 2018.