The Hayabusa2 mission successfully collected a sample from a near-Earth asteroid and returned it to Earth – as well as the first gas sample from deep space, according to the Japan Aerospace Exploration Agency, or JAXA.
The sample was dropped off on Earth by a capsule on December 6 in South Australia. Teams from JAXA were able to retrieve the capsule where it landed and conduct some preliminary tests of gas in the capsule before it was sent to Japan.
The gas was the first step in helping the researchers to confirm that the spacecraft successfully collected a sample from Ryugu in 2019 when the spacecraft visited the asteroid.
Researchers confirmed that the gas originated from Ryugu because their analysis of the gas shows that it is different from the atmospheric composition on Earth. Two separate analyses, one in Australia on December 7 and another between December 10 to 11 at the Extraterrestrial Sample Curation Center on the JAXA Sagamihara Campus, helped the teams arrive at the same result.
The gas likely came from the collected material on the surface and beneath the surface of the asteroid itself.
The researchers will continue opening the capsule containing the sample to understand more about the gas.
The team also confirmed that black sand grains are also inside the sample container, further confirmation that there is asteroid material inside the capsule.
By the end of 2021, JAXA will share tiny samples from Ryugu to six teams of scientists across the globe.
Meanwhile, Hayabusa2 continues on its path after flying by Earth in early December to drop off the capsule and will visit more asteroids in the future.
Hayabusa2 launched on December 3, 2014, and arrived at the near-Earth asteroid Ryugu in June 2018. The spacecraft collected one sample from the asteroid’s surface on February 22, 2019, then fired a copper “bullet” into the asteroid to create a 33-foot wide impact crater. A sample was collected from this crater on July 11, 2019.
Then, Hayabusa2 departed the asteroid in November 2019 and journeyed back to Earth.
Altogether, the mission’s science team believes 1 gram of material was collected, but they can’t be sure until they open it.
“One gram may sound small, but for us, one gram is huge,” said Masaki Fujimoto, deputy director general of the department of solar system sciences at JAXA, during an online briefing hosted by the Australian Science Media Centre. “It is enough to address our science questions.”
The agency’s first Hayabusa mission returned samples from the asteroid Itokawa to Earth in June 2010, but scientists said that due to failure of the spacecraft’s sampling device, they were only able to retrieve micrograms of dust from the asteroid.
“Ryugu is linked to the process that made our planet habitable,” Fujimoto said. “Earth was born dry; it didn’t begin with water. We think distant bodies like Ryugu came to the inner part of solar system, hit Earth, delivered water and made it habitable. That’s the fundamental question we’re after and we need samples to solve that.”
Hayabusa2 will fly by three asteroids between 2026 and 2031, eventually reaching the rapidly rotating micro-asteroid 1998 KY26 in July 2031 millions of miles from Earth. It will be the first flyby of this type of asteroid.
The NASA OSIRIS-REx mission recently collected a sample from another near-Earth asteroid, Bennu, that is similar in composition to Ryugu. In fact, based on early data from both missions, scientists working on both missions believe it’s possible these two asteroids once belonged to the same larger parent body before it was broken apart by an impact.
The Bennu sample will be returned to Earth by 2023.
Patrick Michel, director of research at the French National Centre for Scientific Research in Paris, is an investigator for both missions.
“It is really important to realize that no two asteroids are the same,” Michel told CNN in October. “Even if Bennu and Ryugu share some intriguing similarities and belong to the same category (primitive), they also have some very interesting differences. And these samples will occupy generations of researchers as a large amount will be kept for future generations that will benefit from the increase in technology and accuracy of the instruments used to analyze them.”