Japanese spacecraft touched down briefly on the Ryugu asteroid, fired a bullet, collected pieces of the ejected material and ascended from the space rock.

Yesterday (Feb. 21; Feb. 22 Japan time) the Hayabusa2 probe successfully landed on an asteroid 300 million kilometers away. The spacecraft fired a 0.2-ounce (5 grams) tantalum “bullet” into the boulder-strewn rock at close range, and collected pieces of the ejected material using its specialized “sampling horn,” JAXA officials said during a press conference yesterday evening.

A live webcast of the control room showed dozens of JAXA staff members nervously monitoring data ahead of the touchdown before exploding into applause after receiving a signal from Hayabusa2 that it had landed.

“We made a successful touchdown, including firing a bullet” into the Ryugu asteroid, Yuichi Tsuda, Hayabusa2 project manager, told reporters.

“We made the ideal touchdown in the best conditions,” he said.

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The mission will help us understand the origin of life and the solar system.

The asteroid might contain relatively large amounts of organic matter and water from some 4.6 billion years ago when the solar system was born.

JAXA scientists had expected to find a powdery surface on Ryugu. But tests showed that larger gravel covers the asteroid.

As a result, the team had to carry out a simulation to test whether the projectile would be capable of disturbing enough material to be collected by what scientists call a “sample horn,” which protrudes from the underside of the probe.

This video shows the success of a December 28 test, which green-lit the asteroid landing.

During a later mission, Hayabusa2 will eventually fire an “impactor” to blast out material from underneath Ryugu’s surface. Therefore, allowing the collection of “fresh” materials unexposed to millennia of wind and radiation.

By studying these samples scientists may find answers to some fundamental questions about life and the universe. It will also improve our understanding of whether elements from space helped give rise to life on Earth.

Engineers launched the Hayabusa2 mission in December 2014 and arrived at Ryugu in June of last year. The spacecraft will depart Ryugu in December 2019 and return to Earth by the end of 2020. Scientists such as John Bridges, a professor of planetary science at the University of Leicester, UK, will then analyze that precious cargo of samples.

Communication with the spacecraft

Scientists stop receiving signals from Hayabusa2 at times because its antennas don’t always point toward Earth.

Mission team members announced at about 6:30 p.m. EST (2330 GMT) yesterday that they have issued the order to fire the bullet, and that Hayabusa2 had moved away from Ryugu as planned. But it took a few more hours for them to confirm that the bullet had indeed fired, and that sample collection occurred.

Scientists originally scheduled the probe’s landing for last year. But it was pushed back after surveys found the asteroid’s surface was more rugged than initially thought. Thus, forcing JAXA to take more time to find a suitable landing site.

The mission had already made contact with the asteroid’s surface several times before today’s milestone: In September, the Hayabusa2 mothership dropped two tiny hopping rovers onto the rock, then did the same with a microwave-size lander called MASCOT a few weeks later.

MASCOT’s battery died after about 17 hours of surface work, slightly exceeding its planned operational life span. The two little solar-powered hoppers, named Owl and Hibou, are still going strong.


Astronomers first discovered Ryugu in 1999. It is named after Ryugu-jo, or dragon’s palace — a magical undersea palace in a Japanese folk tale.

However, this space rock, as dark as coal, is a C-type, or carbonaceous, asteroid, meaning it is full of carbon molecules known as organics including possibly amino acids, the building blocks of proteins. Such molecules are not always associated with biology and can form from chemical reactions in deep space, but asteroids could have seeded Earth with the organic matter that led to life.

About three-quarters of asteroids in the solar system fall into the C-type.

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Thumbnail image: Japan’s Hayabusa2 spacecraft captured this photo during its sample-grabbing descent toward the asteroid Ryugu on Feb. 21, 2019. The probe’s shadow is visible on the space rock’s surface. Credit: JAXA