In a streak of light across the night sky, samples collected from a distant asteroid arrived on Earth on Sunday after being dropped off by Japanese space probe Hayabusa-2.
Scientists hope the precious samples, which are expected to amount to no more than 0.1 grams of material, could help shed light on the origin of life and the formation of the universe
The capsule carrying samples entered the atmosphere just before 2:30 am Japan time (1730 GMT Saturday), creating a shooting-star-like fireball as it entered Earth's atmosphere.
"Six years and it has finally come back to Earth," an official narrating a live broadcast of the arrival said, as images showed officials from Japan's space agency JAXA cheering and pumping their fists in excitement.
The capsule separated from Hayabusa-2 on Saturday, when the refrigerator-sized space probe that launched into space in 2014 was 220,000 kilometres (137,000 miles) away from Earth.
It landed in the southern Australian desert, where it will be recovered from an area spanning some 100 square kilometres, with search crews guided by beacons emitted as the capsule descended.
Scientists at the Royal Australian Air Force's (RAAF) Woomera Range Complex in South Australia closely monitored the capsule's descent.
Samples in the capsule were collected from the asteroid Ryugu, some 300 million kilometres from Earth during two crucial phases of Hayabusa-2's mission last year.
The probe collected both surface dust and pristine material from below the surface that was stirred up by firing an "impactor" into the asteroid.
The material collected from the asteroid is believed to be unchanged since the time the universe was formed.
Larger celestial bodies like Earth went through radical changes including heating and solidifying, changing the composition of the materials on their surface and below
But "when it comes to smaller planets or smaller asteroids, these substances were not melted, and therefore it is believed that substances from 4.6 billion years ago are still there," Hayabusa-2 mission manager Makoto Yoshikawa told reporters before the capsule arrived
- Samples with organic material? -
Scientists are especially keen to discover whether the samples contain organic matter, which could have helped seed life on Earth.
"We still don't know the origin of life on Earth and through this Hayabusa-2 mission, if we are able to study and understand these organic materials from Ryugu, it could be that these organic materials were the source of life on Earth," Yoshikawa said.
Once the samples are recovered, they will be processed in Australia and then flown back to Japan.
Half the material will be shared between JAXA, US space agency NASA and other international organisations, and the rest kept for future study as advances are made in analytic technology
- More tasks for Hayabusa-2 -
The work isn't over for Hayabusa-2, which was launched in December 2014.
The probe will now begin an extended mission targeting two new asteroids.
Hayabusa-2 will complete a series of orbits around the sun for around six years before approaching the first of its target asteroids -- named 2001 CC21 -- in July 2026.
The probe won't get that close, but scientists hope it will be able to photograph it and that the fly-by will help develop knowledge about how to protect Earth against asteroid impact.
Videographic presentation of the Hayabusa-2 mission
Hayabusa-2 will then head towards its main target, 1998 KY26, a ball-shaped asteroid with a diameter of just 30 metres. When the probe arrives at the asteroid in July 2031, it will be approximately 300 million kilometres from Earth.
It will observe and photograph the asteroid, no easy task given that it is spinning rapidly, rotating on its axis about every 10 minutes.
But Hayabusa-2 is unlikely to land and collect samples, as it probably won't have enough fuel to return them to Earth.
kh-sah/ch/acb
Japan capsule with asteroid samples retrieved in Australia
TOKYO — Japan’s space agency said its helicopter search team has retrieved a capsule, which is carrying asteroid samples that could explain the origin of life, that landed on a remote area in southern Australia as planned Sunday.
“The capsule collection work at the landing site was completed . . .," the space agency said in a tweet about four hours after the capsule landed. ”We practiced a lot for today ... it ended safe."
Hayabusa2 had successfully released the small capsule on Saturday and sent it toward Earth to deliver samples from a distant asteroid that could provide clues to the origin of the solar system and life on our planet, the Japan Aerospace Exploration Agency said.
Early Sunday the capsule briefly turned into a fireball as it reentered the atmosphere 120 kilometres (75 miles) above Earth. At about 10 kilometres (6 miles) above ground, a parachute was opened to slow its fall and beacon signals were transmitted to indicate its location.
“It was great ... It was a beautiful fireball, and I was so impressed," said JAXA's Hayabusa2 project manager Yuichi Tsuda as he celebrated the successful capsule return and safe landing from a command centre in Sagamihara, near Tokyo. “I've waited for this day for six years."
Beacon signals were detected, suggesting the parachute successfully opened and the capsule landed safely in a remote, sparsely populated area of Woomera, Australia, said JAXA official Akitaka Kishi.
About two hours after the capsule's reentry, JAXA said its helicopter search team found the capsule in the planned landing area. The retrieval of the pan-shaped capsule, about 40 centimetres (15 inches) in diameter, was completed about two hours later.
The fireball could be seen even from the International Space Station. A Japanese astronaut, Soichi Noguchi, who is now on a six-month mission there, tweeted: “Just spotted #hayabusa2 from #ISS! Unfortunately not bright enough for handheld camera, but enjoyed watching capsule!”
Hayabusa2 left the asteroid Ryugu, about 300 million kilometres (180 million miles) away, a year ago. After it released the capsule, it moved away from Earth to capture images of the capsule descending toward the planet as it set off on a new expedition to another distant asteroid.
The capsule descended from 220,000 kilometres (136,700 miles) away in space after it was separated from Hayabusa2 in a challenging operation that required precision control.
JAXA officials said they hoped to conduct a preliminary safety inspection at an Australian lab and bring the capsule back to Japan early next week.
Dozens of JAXA staff have been working in Woomera to prepare for the sample return. They set up satellite dishes at several locations in the target area inside the Australian Air Force test field to receive the signals.
Australian National University space rock expert Trevor Ireland, who was in Woomera for the arrival of the capsule, said he expected the Ryugu samples to be similar to the meteorite that fell in Australia near Murchison in Victoria state more than 50 years ago.
“The Murchison meteorite opened a window on the origin of organics on Earth because these rocks were found to contain simple amino acids as well as abundant water,” Ireland said. “We will examine whether Ryugu is a potential source of organic matter and water on Earth when the solar system was forming, and whether these still remain intact on the asteroid.”
Scientists say they believe the samples, especially ones taken from under the asteroid’s surface, contain valuable data unaffected by space radiation and other environmental factors. They are particularly interested in analyzing organic materials in the samples.
JAXA hopes to find clues to how the materials are distributed in the solar system and are related to life on Earth. Yoshikawa, the mission manager, said 0.1 gram of the dust would be enough to carry out all planned researches.
For Hayabusa2, it’s not the end of the mission it started in 2014. It is now heading to a small asteroid called 1998KY26 on a journey slated to take 10 years one way, for possible research including finding ways to prevent meteorites from hitting Earth.
So far, its mission has been fully successful. It touched down twice on Ryugu despite the asteroid’s extremely rocky surface, and successfully collected data and samples during the 1 1/2 years it spent near Ryugu after arriving there in June 2018.
In its first touchdown in February 2019, it collected surface dust samples. In a more challenging mission in July that year, it collected underground samples from the asteroid for the first time in space history after landing in a crater that it created earlier by blasting the asteroid’s surface.
Asteroids, which orbit the sun but are much smaller than planets, are among the oldest objects in the solar system and therefore may help explain how Earth evolved.
Ryugu in Japanese means “Dragon Palace,” the name of a sea-bottom castle in a Japanese folk tale.
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Mari Yamaguchi, The Associated Press