The Japanese asteroid Hayabusa2 ends with a hunt in the far reaches of Australia


Japan’s space agency is nearing the end of a journey of discovery aimed at shedding light on the earliest eons of the solar system and possibly providing clues as to the origin of life on Earth.

First, however, you have to embark on a waste hunt on the Australian outskirts.

This weekend, pieces of an asteroid land in a barren region near Woomera, South Australia. These are Hayabusa2, a robotic space probe launched by JAXA, the Japanese space agency, in 2014 to explore an asteroid called Ryugu, a dark, carbon-rich rock just over half a mile wide.

The success of the mission and the science it produces will increase Japan’s status as a central player in deep space research, along with NASA, the European Space Agency and Russia. JAXA currently has a spacecraft in orbit around Venus, studying the hellish climate of the planet and collaborating with Europeans on a mission to Mercury.

In the coming years, Japan plans to bring rocks back from Phobos, the moon of Mars, and contribute to NASA’s Artemis program, which will send astronauts to the Earth’s moon.

But the immediate challenge in the darkness is finding a 16-inch-wide capsule that contains asteroid patterns, somewhere between hundreds of square miles north of Adelaide, 280 miles from the nearest big city.

“It’s actually in the middle of nowhere,” said Shogo Tachibana, senior researcher responsible for analyzing Hayabusa2 samples. He is a member of a team of more than 70 Japanese who came to Woomera to recover the capsule. The area used for testing by the Australian Army provides ample free space, ideal for the return of an interplanetary probe.

The small return capsule separated from the main spacecraft about 12 hours before the planned landing, when it was about 125,000 miles from Earth. JAXA will broadcast the capsule live on Saturday at 11:30 a.m. Eastern Time. (Sunday will be before dawn in Australia.)

The capsule is expected to land a few minutes before noon.

Makoto Yoshikawa, the manager of the mission, said in an interview that there is an uncertainty of about 10 kilometers, or about six miles, in determining when the capsule will be released back into the atmosphere. At a height of six miles, the capsule lowers a parachute and where it sinks down, increasing the uncertainty.

“The place of landing depends on the edge of the day,” Dr. Yoshikawa said. The area that search engines may need to cover could provide about 60 miles, he said.

The trajectory of the superheated air fireball created by the re-entering capsule as well as the capsule radio indicator help guide the recovery team. The task will be much more difficult if the transmitter fails or if the parachute is not installed.

There is also a little rush. The team hopes to get the capsule back, do the first analysis and pull it back to Japan within 100 hours. Even though the capsule is sealed, the problem is that the Earth’s air is slowly seeping in. “There is no perfect closure,” Dr. Tachibana said.

Once the capsule is found, a helicopter takes it to a laboratory set up at the Australian Air Force base in Woomera. An instrument recovers from the inside of the capsule any gas that the rocks of the asteroid could have released when they were shaken and broken during re-entry. Dr. Yoshikawa said scientists also want to know if they can detect helium solar wind particles that have slammed into the asteroid and embedded in the rocks.

The gases would also reassure scientists that Hayabusa2 has indeed successfully collected samples from Ryugu. At least 0.1 gram, or less than 1/280 ounce, is required to declare success. The hope is that the spaceship brought back more grams.

In Japan, the Hayabusa2 team begins analyzing Ryugu samples. After about a year, some of the samples will be shared with other scientists for further study.

In order to collect the samples, Hayabusa2 arrived at the asteroid in June 2018. He conducted a series of studies, each with increasing technical complexity. He dropped probes on Ryugu’s surface, blew a hole in the asteroid to see what was under it, and descended to the surface twice to grab the small pieces of the asteroid. This operation proved to be a much bigger challenge than expected due to the many stones on the surface.

Small worlds like Ryugu used to be of little interest to planetary scientists who focused on studying the planets, said Masaki Fujimoto, deputy director general of the Institute of Space and Astronomy, part of JAXA. – Smaller bodies, who cares? he said. “But if you are serious about the evolution of planetary systems, small bodies matter.”

Examining the water trapped in minerals from Ryugu could give hints if the water in the Earth’s oceans came from asteroids and if carbon-based molecules could have created a nucleus for life.

Some of the Ryugu samples will go to NASA, which will bring back some rocks and soil from another asteroid with the OSIRIS-REX mission. The OSIRIS-REX spacecraft has studied a smaller, carbon-rich asteroid called Bennu, and will return to Earth next spring, dropping its rock samples in September 2023.

Ryugu and Bennu proved surprisingly similar in some respects, both seeming to have braided tops and rock-covered surfaces, but differently in different ways. The rocks in Ryugu seem to contain much less water. The significance of the similarities and differences will only become clear if scientists study the rocks in more detail.

“When the OSIRIS-REX sample returns, we can learn the lessons of the Hayabusa2 mission,” said Harold C. Connolly Jr., a geology professor at Rowan University in New Jersey and an OSIRIS-REX mission sample scientist. “The similarities and differences are absolutely stunning.”

Dr. Connolly hopes to go to Japan next summer to participate in the analysis of ryugu samples.

Hayabusa2 is not Japan’s first planetary mission. Its name does refer to the existence of Hayabusa, an earlier mission that brought back samples from another asteroid, Itokawa. But this mission, launched in 2003 and returned in 2010, faced serious technical problems. So did the JAXA Akatsuki spacecraft, which is currently orbiting Venus, and which the Japanese agency has managed to put on a scientific mission after years of difficulty. A Japanese mission to Mars also failed in 2003.

In contrast, Hayabusa2’s operations went almost flawlessly, despite the fact that the same general design remained as its predecessor. “There are really no big issues,” said Dr. Yoshikawa, the head of the mission. – Of course, little ones.

He said the team had studied Hayabusa’s failures in detail and made changes as needed, as well as conducted a number of rehearsals to try to anticipate possible incidents.

Japanese missions typically operate on a smaller budget than NASA and therefore often carry fewer assets. Hayabusa2 will cost less than $ 300 million, while OSIRIS-REX will cost about $ 1 billion.

The dropping of Ryugu samples is not over on the Hayabusa2 mission. After releasing the returning capsule, the main spacecraft moved to avoid a collision with Earth, 125 miles missing. Now you’re going to travel to another asteroid, a tiny 1998 KY26 that is only 100 feet in diameter but spins fast and completes a turn in less than 11 minutes.

Hayabusa2 will fly itself with two flies of the Earth towards KY26, finally arriving in 2031. During its extended deep spaceflight, it conducts some astronomical experiments, and the spacecraft still carries one last projectile that it can use to test the spacecraft’s surface.