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 Hayabusa2.
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 a.m.
Japan time, 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 personnel from the
Japan Aerospace Exploration Agency cheering and pumping their fists in
excitement.
A few hours later, JAXA confirmed the samples had been recovered, with help
from beacons emitted by the capsule as it plummeted to Earth after
separating from Hayabusa2 on Saturday, while the fridge-sized probe was some
220,000 km (137,000 miles) away.
“We found the capsule! Together with the parachute! Wow!,” the mission’s
Twitter account tweeted.
The capsule was recovered in the southern Australian desert, and will now be
processed before being sent to Japan.
The samples were collected by Hayabusa2, which launched in 2014, from the
asteroid Ryugu, some 300 million km from Earth.
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,” Hayabusa2 mission manager Makoto
Yoshikawa told reporters before the capsule arrived.
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 Hayabusa2
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.
“We’ve never had materials like this before … water and organic matters will
be subject to research, so this is a very valuable opportunity,” said Motoo
Ito, senior researcher at the Japan Agency for Marine-Earth Science and
Technology.
Half the Hayabusa2’s samples will be shared between JAXA, U.S. space agency
NASA and other international organizations, and the rest kept for future study
as advances are made in analytic technology.
The work isn’t over for Hayabusa2, which will now begin an extended mission
targeting two new asteroids.
It 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.
Hayabusa2 will then head toward its main target, 1998 KY26, a ball-shaped
asteroid with a diameter of just 30 meters. When the probe arrives at the
asteroid in July 2031, it will be approximately 300 million km 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 Hayabusa2 is unlikely to land and collect samples, as it probably won’t
have enough fuel to return them to Earth.
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Space & Astrophysics