Hayabusa-2 successfully touches down on asteroid Ryugu
The Japanese Aerospace Exploration Agency (JAXA) launched Hayabusa-2, its second asteroid sample return mission, in December 2014. It arrived at its destination, a carbonaceous near-Earth asteroid, in late June of 2018.
To ease sample collection, the spacecraft fired a bullet composed of metal tantalum at Ryugu’s surface with the goal of creating fragments small enough for collection in a receptacle known as a “sample horn.” This method was used after having been successfully tested on Earth.
Queen guitarist and astrophysicist Brian May, who has processed some images of Ryugu returned by the spacecraft, took part in a livestream of the event.
After firing the bullet, Hayabusa-2 lifted off Ryugu’s surface. Over the next two months, the spacecraft, which is equipped with many such bullets, is expected to conduct several more sample collection attempts using the same technique. The probe will also create an artificial crater on Ryugu, from which it will collect samples, by exploding a small impactor on the asteroid’s surface.
Hayabusa-2 has already dropped two rovers and a lander onto Ryugu to serve as landmarks, but did not itself touch down until now. One of these, the Mascot lander, photographed the asteroid’s dark surface, operating for 17 hours until its batteries died.
Like Ryugu, three quarters of the asteroids in the belt between Mars and Jupiter are carbonaceous, meaning they contain carbon molecules, which are organic and make up the building blocks of life. These molecules are not necessarily the product of biological activity; however, their presence intrigues scientists because asteroids like Ryugu may have brought organic matter to Earth, which could have played a role in the development of life.
Ryugu is also believed to have water ice and materials dating back to the solar system’s earliest days. Asteroids are remaining fragments from the original protoplanetary disk that surrounded the young Sun 4.5 billion years ago.
Scientists will not know how much of this and other samples were collected until Hayabusa-2 returns them to Earth in 2020.
This mission is the second asteroid sample return for JAXA, which successfully returned 1,500 sample particles from the asteroid Itokawa via its first Hayabusa lander in 2010. OSIRIS-REx, a NASA mission, is scheduled to retrieve samples from the asteroid Bennu in 2020 and return them to Earth in 2023.
Video courtesy of JAXA
Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.