The Japanese space agency is nearing the end of its discovery journey, which aims to shed light on the earliest eons of the solar system and possibly give evidence of the origin of life on Earth.
But first he will have to go hunting for scavengers in the Australian outback.
This weekend, pieces of the asteroid will land in a barren region near Woomera, South Australia. They are sent to Earth by Hayabusa2, a robotic space probe launched by JAXA, the Japanese space agency, in 2014 to study an asteroid named Ryugu, a dark, carbon-rich rock just over half a mile wide.
In the coming years, Japan plans to return rocks from Phobos, a moon on Mars, and contribute to NASA’s Artemis program to send astronauts to Earth’s moon.
But the immediate challenge will be to search in the dark for a 16-inch-wide capsule containing asteroid samples somewhere in the hundreds of square miles in a region 280 miles north of Adelaide, the nearest major city.
“It’s really in the middle of nowhere,” said Shogo Tachibana, the lead researcher responsible for analyzing Hayabusa’s samples. He is part of a team of over 70 people from Japan who have arrived at Woomera to restore the capsule. The area used by the Australian military for testing provides a wide open space that is ideal for the return of an interplanetary probe.
The small return capsule separates from the main spacecraft about 12 hours before the planned landing, when it is about 125,000 miles from Earth. JAXA will broadcast live coverage of the capsule landing, starting at 11:30 a.m. Eastern Time on Saturday. (It will be hours before dawn in Australia on Sunday.)
The capsule is expected to hit the ground a few minutes before noon.
In an interview, Makoto Yoshikawa, the head of the mission, said there was uncertainty about 10 kilometers or about six miles to determine where the capsule would re-enter the atmosphere. At an altitude of six miles, the capsule will release a parachute and, where it will deviate on descent, will add to the uncertainty.
“The landing site depends on the wind that day,” said Dr. Yoshikawa. The area that searchers may need to cover could extend about 60 miles, he said.
The trace of the fireball of overheated air created by the re-entering capsule will help guide the recovery team, as will the capsule radio beacon. The task will become much more difficult if the lighthouse fails or if the parachute fails to deploy.
There is also haste. The team hopes to restore the capsule, perform an initial analysis and return it to Japan within 100 hours. Although the capsule is sealed, the concern is that the earth’s air will slowly flow inward. “There is no perfect seal,” said Dr. Tachibana.
Once the capsule is found, a helicopter will take it to a laboratory set up at the Australian Air Force Base in Woomera. There, the instrument will extract any gases in the capsule that may have been released from the asteroid rocks as they were shaken and broken during re-entry. Dr Yoshikawa said scientists would also like to see if they could detect any helium particles from the solar wind that hit the asteroid and embedded in the rocks.
The gases would also reassure scientists that Hayabusa2 has indeed successfully collected samples from Ryugu. A minimum of 0.1 grams or less than 1 / 280th ounce is required to declare success. The hope is that the spacecraft will return a few grams.
In Japan, the Hayabusa2 team will begin analyzing Ryugu samples. In about a year, some of the samples will be shared with other scientists for further study.
To collect these samples, Hayabusa2 arrived at the asteroid in June 2018. He conducted a series of studies, each with increasing technical complexity. He dropped probes on the surface of Ryugu, drilled a hole in the asteroid to peek into what lay beneath, and twice descended to the surface to catch small pieces of the asteroid, an operation that proved much more challenging 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 for Space and Astronautics, part of JAXA. “Insignificant bodies, who cares?” He said. “But if you’re serious about forming planetary systems, small bodies actually matter.”
The study of water trapped in minerals from Ryugu may suggest whether the water in the Earth’s oceans comes from asteroids and whether carbon-based molecules could have been building up lifelong building blocks.
Some of Ryugu’s samples will go to NASA, which is returning some rocks and soil from another asteroid with its OSIRIS-REX mission. The OSIRIS-REX spacecraft is exploring a smaller carbon-rich asteroid named Bennu and will launch back to Earth next spring, leaving the rock samples in September 2023.
Ryugu and Bennu turned out to be surprisingly similar in some respects, both looking like rotating peaks and with surfaces covered with stones but different in other ways. The rocks of Ryugu seem to contain much less water. The significance of the similarities and differences will become clear only after scientists study the rocks in more detail.
“When the OSIRIS-REX sample returns, we will have lessons learned from the Hayabusa2 mission,” said Harold Connelly Jr., a professor of geology at Rowan University in New Jersey and a scientist for the OSIRIS-REX mission. “The similarities and differences are absolutely fascinating.”
Dr. Connelly hopes to go to Japan next summer to participate in the Ryugu sample analysis.
Hayabusa2 is not Japan’s first planetary mission. In fact, its name points to the existence of Hayabusa, an earlier mission that returned samples from another asteroid, Itokawa. But this mission, which started in 2003 and returned in 2010, faced major technical problems. So did JAXA’s Akatsuki spacecraft, which is currently in orbit around Venus, which the Japanese agency was able to restore on a scientific mission after years of hardship. A Japanese mission to Mars also failed in 2003.
In contrast, Hayabusa2’s operations went almost flawlessly, although it retains the same overall design as its predecessor. “There aren’t really any big problems,” said Dr. Yoshikawa, 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 conducting numerous rehearsals to try to anticipate any unforeseen situations.
Japanese missions typically work with smaller budgets than NASA’s and therefore often carry fewer tools. The cost of Hayabusa2 is under $ 300 million, while the cost of OSIRIS-REX will be around $ 1 billion.
The dropping of the Ryugu samples is not the end of the Hayabusa2 mission. After the return capsule was released, the main spacecraft shifted course to avoid a collision with Earth that disappeared 125 miles away. It will now travel to another small asteroid, designated the 1998 KY26, which is only 100 feet in diameter but rotates quickly, completing one spin in less than 11 minutes.
Hayabusa2 will use two Earth flights to launch to KY26, finally arriving in 2031. It will conduct some astronomical experiments during its long journey into deep space, and the spacecraft is still carrying the last projectile, which can be used to test the surface of this cosmic rock.