TOKYO (Kyodo) -- More than 20 types of amino acids have been detected in samples Japan's Hayabusa2 space probe brought to Earth from an asteroid in late 2020, an official said Monday.
The acids discovered are very important substances for living things and could hold clues to understanding the origins of life, the education ministry official said.
In December 2020, a capsule that had been carried on a six-year mission by Hayabusa2 delivered more than 5.4 grams of surface material to Earth from the Ryugu asteroid, located over 300 million kilometers away.
The probe of Ryugu was aimed at unraveling the mysteries of the origin of the solar system and life. Previous analysis of the samples had suggested the presence of water and organic matter.
The full-fledged investigation of the sample was launched in 2021 by the Japan Aerospace Exploration Agency and research institutions nationwide including the University of Tokyo and Hiroshima University.
Amino acids are substances that make proteins and are indispensable for life.
Although it is not known how amino acids arrived on ancient Earth, one theory says they were brought by meteorites, with amino acids being detected in a meteorite found on Earth. But there is also a possibility that they were attached on the ground.
Hayabusa2 delivered the subsurface materials to Earth without them being exposed to outside air after collecting the samples that had not been weathered by sunlight or cosmic rays.
The discovery of amino acids showed for the first time that they exist on an asteroid in space.
Hayabusa2 left Earth in 2014 and reached its stationary position above Ryugu in June 2018 after traveling 3.2 billion km on an elliptical orbit around the sun for more than three years.
The probe touched down on the asteroid twice the following year, collecting the first-ever subsurface samples from an asteroid.