Japan’s Aerospace Exploration Agency said its staff initially saw some black particles at the bottom of the capsule’s sample collector when they removed the container on Monday.
By Tuesday, scientists found more soil and gas samples in a compartment that stored those from the first of two Hayabusa landings on the asteroid last year.
“We have confirmed a fair amount of sand apparently collected from the asteroid Ryugu, along with gases,” JAXA Hayabusa2 project manager Yuichi Tsuda said in a video message during an online press conference.
“The samples from outside our planet, which we have always dreamed of, are now in our hands.”
Tsuda called the successful return of the asteroid’s gas and soil samples “an important scientific milestone.”
The 40-centimeter-diameter dish-shaped capsule was launched by Hayabusa2 from space to a predetermined location in a sparsely populated Australian desert on December 6 at the end of its six-year round trip to Ryugu, more than 300 million kilometers from Earth.
The capsule arrived in Japan last Tuesday for research that scientists hope will provide insight into the origins of the solar system and life on Earth.
Hirotaka Sawada, a JAXA scientist, was the first to look inside the capsule’s sample receiver.
Mr. Sawada said he was “almost speechless” with joy when he discovered that the samples inside included some that were, as expected, the size of dust, but also some the size of pebbles.
The soil samples in the photos shown in Tuesday’s presentation looked like piles of dark coffee grounds mixed with granules.
Sawada said the hermetically sealed capsule successfully recovered asteroid gases that are distinctly different from the air on Earth – a first sample of gas return from outer space. Kyushu University scientist Ryuji Okazaki said the gases could be related to minerals in the asteroid soil and that he hopes to identify the gaseous samples and determine their age.
Scientists hope that samples from the asteroid’s subsurface could provide information from billions of years ago that is not affected by space radiation and other environmental factors.
JAXA scientists say they are particularly interested in the organic materials in the samples to find out how they were distributed in the solar system and if they are related to life on Earth.
Sei-ichiro Watanabe, an earth and environment scientist at Nagoya University who works with JAXA, said having more sample material to work with than expected is great news as it will broaden the scope of the studies.
The samples came from two touchdowns Hayabusa2 made last year at Ryugu. The landings were more difficult than expected due to the extremely rocky surface of the asteroid.
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The first landing collected samples from Ryugu’s surface and the second from underground. Each was stored separately.
JAXA said it will search another compartment, used for a second landing, next week, and will continue an initial examination before further studies of the material.
Following the studies in Japan, some of the samples will be shared with NASA and other international space agencies for further research starting in 2022.
Hayabusa2, meanwhile, is now on an 11-year expedition to another asteroid to try to study possible defenses against meteorites that could fly toward Earth.