National / Science & Health

Japan's Hayabusa2 probe succeeds in blasting out first man-made crater on an asteroid


Scientists have succeeded in creating what they called the first-ever artificial crater on an asteroid, a step toward shedding light on how the solar system evolved, the Japan Aerospace Exploration Agency said Thursday.

The announcement comes after the Hayabusa2 probe fired an explosive device April 5 at the Ryugu asteroid, around 340 million kilometers from Earth, to blast a crater in the surface and scoop up material, aiming to reveal more about the origins of life on Earth.

Yuichi Tsuda, Hayabusa2 project manager, told reporters they confirmed the crater from images captured by the probe located 1,700 meters (5,500 feet) from the asteroid’s surface.

“Creating an artificial crater with an impactor and observing it in detail afterward is a world-first attempt,” Tsuda said. “This is a big success.”

NASA’s Deep Impact probe succeeded in creating an artificial crater on a comet in 2005, but only for observation purposes.

The JAXA probe photographed the area hit by the projectile from a distance of 1.7 km, according to the agency, which compared images of the asteroid’s surface before and after the shooting of the metal bullet, and determined the presence of a man-made crater measuring about 10 meters across.

Masahiko Arakawa, a Kobe University professor involved in the project, said it was “the best day of his life.”

“We can see such a big hole a lot more clearly than expected,” he said.

JAXA scientists had previously predicted that the crater could be as large as 10 meters in diameter if the surface was sandy, or three meters if it was rocky.

“The surface is filled with boulders but yet we created a crater this big. This could mean there’s a scientific mechanism we don’t know or something special about Ryugu’s materials,” the professor said.

Rocks had been moved and dislodged from their previous location, while there was a dark area about 40 meters long on the surface, considered to be debris created from the impact.

Hayabusa2, which began its descent toward the asteroid Wednesday afternoon, captured images of its surface to determine the existence of the crater.

Hayabusa2 shot a copper “impact head” at Ryugu. The agency confirmed a burst of debris caused by the collision.

The aim of blasting the crater on Ryugu is to throw up “fresh” material from under the asteroid’s surface that could shed light on the early stages of the solar system.

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

In February, Hayabusa2 touched down briefly on Ryugu to collect surface samples and found hydrated minerals that will help scientists determine whether asteroids brought water to Earth as hypothesized.

The mission, with a price tag of around ¥30 billion, was launched in December 2014 from the Tanegashima Space Center in Kagoshima Prefecture, and Hayabusa2 reached Ryugu last June. It is scheduled to return to Earth with its samples in 2020.

Photos of Ryugu — which means “Dragon Palace” in Japanese and refers to a castle at the bottom of the ocean in an ancient Japanese tale — show the asteroid has a rough surface covered with boulders.

Although the initial plan was to focus the blast to within 200 meters of the target, the team said they had hit within 10 to 20 meters of it.

“There was a very high level of accuracy,” Tsuda said. “We were able to create a crater in the area we had aimed for.”

The team will continue to analyze the results and determine whether there is an appropriate area on Ryugu’s surface they can land the space probe on in order to collect a sample of rocks from the asteroid.

Asteroids like Ryugu are often likened to fossils holding the preserved traces of the time when the solar system was born. But the effects of solar winds have weathered Ryugu’s surface, making it necessary to dig deep under it in order to collect such materials.