Japanese space probe to bring asteroid dust to Earth

Call it a special delivery: After six years in space, Japan’s Hayabusa-2 probe is returning home, but only to release its rare asteroid samples before embarking on a new mission.

The refrigerator-sized probe, launched in December 2014, has already wowed scientists by landing and collecting material from an asteroid some 300 million kilometers (185 million miles) from Earth.

But its work isn’t done yet, with scientists from Japan’s JAXA space agency planning to extend its mission over a decade and target two new asteroids.

Before that mission can begin, Hayabusa-2 must leave his precious samples from the asteroid Ryugu, “dragon palace” in Japanese.

“The probe is now in excellent condition,” project manager Yuichi Tsuda said on Friday, hailing its return as “a rare event in human history.”

Scientists hope it will bring about 0.1 grams of material that will offer clues as to what the solar system looked like when it was born some 4.6 billion years ago.

The samples could shed light on “how matter is scattered throughout the solar system, why it exists on the asteroid and how it is connected to Earth,” Tsuda told reporters ahead of Sunday’s release.

The material is in a capsule that will separate from Hayabusa-2 as it is approximately 220,000 kilometers above the Earth and then crash into the South Australian desert.

The samples were collected during two crucial phases of the mission last year.

In the first, Hayabusa-2 landed on Ryugu to collect dust before firing an “impactor” to lift pristine material from beneath the surface. Months later, he landed to collect more samples.

“We may be able to obtain substances that will give us clues to the birth of a planet and the origin of life … I am very interested in seeing the substances,” mission leader Makoto Yoshikawa told reporters.

Protected from sunlight and radiation inside the capsule, the samples will be collected, processed, then flown to Japan.

Half of the material will be shared between JAXA, the US space agency NASA and other international organizations, and the rest will be kept for future study as advances in analytical technology are made.

Two new asteroid targets

After releasing its samples, Hayabusa-2 will complete a series of orbits around the sun for about six years, recording dust data in interplanetary space and observing exoplanets.

It will then approach the first of its target asteroids in July 2026.

The spacecraft won’t get that close to asteroid 2001 CC21, but scientists hope it will be able to photograph it completing a “high-speed flight”.

Getting that close could also help develop knowledge on how to protect Earth from asteroid impact.

Hayabusa-2 will then head towards its main target, 1998 KY26, a ball-shaped asteroid with a diameter of just 30 meters. When the spacecraft arrives on the asteroid in July 2031, it will be about 300 million kilometers from Earth

And the lens poses significant new challenges, not least because it rotates rapidly, rotating on its axis every 10 minutes or so.

Hayabusa-2 will observe and photograph the asteroid, but is unlikely to land and collect samples, as it likely won’t have enough fuel to bring them back to Earth.

However, even getting to the asteroid will be a challenge, said Seiichiro Watanabe, a project scientist on the Hayabusa-2 spacecraft and professor of planetary sciences at the University of Nagoya.

“He is like an athlete who scored two goals in a rugby world cup game trying to compete in the Olympics, 10 years after moving into figure skating,” he told reporters.

“We never expected Hayabusa-2 to serve another mission … but it’s a scientifically significant and fascinating plan.”

The mission extension carries risks, including the fact that Hayabusa-2’s equipment will degrade in deep space, but it also offers a rare and relatively inexpensive way to continue research.

The spacecraft is the successor to JAXA’s first asteroid explorer “Hayabusa”, which is Japanese for hawk.

That probe brought back dust samples from a smaller potato-shaped asteroid in 2010 after a seven-year odyssey and was hailed as a scientific triumph.

© 2020 AFP