Ryugu asteroid sample return provides a natural laboratory for primordial chemical evolution

Abstract

The samples returned from near-Earth asteroid (162173) Ryugu provide a pristine record of the 4.6 billion years since the birth of the Solar System. The Hayabusa2 initial analysis team has integrated a range of analytical techniques to investigate Ryugu’s organic chemistry. Here, we highlight their latest findings, the potential questions which may be answered, and provide an overview of new prospects in the decade to come.

Primordial aqueous alteration recorded in water-soluble organic molecules from the carbonaceous asteroid (162173) Ryugu

“…We hope that the Bennu sample will reveal detailed information on chemical evolution and molecular chirality 6 , 11 , 40 , 54 , including widely diverse hydrophilic molecules in the asteroid history. Notably, the carbonate veins observed on some boulders at Bennu 55 are unique and should reveal interactions between pristine aqueous alteration processes, as discussed in this paper and other perspectives 7 , 53 , 56 . Therefore, we conclude here that carbonaceous asteroids are natural laboratories for observing realistic primordial molecular evolution in organic and inorganic contexts.…”

“…Pristine samples from the near-Earth asteroid (162173) Ryugu returned to Earth by the Hayabusa2 spacecraft provided a valuable opportunity to reveal the organic astrochemistry preserved for over 4.6 billion years in the Solar System 1 – 4 . This unique opportunity for investigating primordial organic molecules illuminates several scientific contexts involving carbonaceous asteroids, including the following questions 5 – 7 : What is the role of carbonaceous asteroids in the Solar System history? What are the origins and characteristics of the light elements, e.g., carbon (C), nitrogen (N), hydrogen (H), oxygen (O), and sulfur (S)?…”

Synthesis and applications of helical polymers with dynamic and static memories of helicity

“…The chiral amino acids detected in Ryugu were concluded to be approximately racemic based on the most advanced enantioseparation and detection technologies currently available, as well as by taking into account the possibility of terrestrial contamination on Earth. 120 ) As a result, the origin of homochirality on Earth remains unresolved, 121 ) but further analysis of samples from other comets and asteroids will provide a solution to this mystery.…”

The extraterrestrial search for our own chemical origins

“…the best of both worlds), we need sample return missions. So far, samples have been brought back from our moon 10 by the Apollo, Luna, and Chang’e-5 missions; the comet Wild 2/81P by Stardust; the near-Earth asteroids Ikotawa and Ryugu 11 by Hayabusa 1 and 2; and now from Bennu by OSIRIS-REX. Robotic missions delivering samples collected from extraterrestrial environments to clean terrestrial laboratories may be technically demanding, but it allows pristine samples to be interrogated with the most advanced, cutting-edge analytical techniques.…”