How we got here: Back in 2019, the Japan Aerospace Exploration Agency (JAXA) successfully collected samples of the near-Earth asteroid 162173 Ryugu using its Hayabusa2 spacecraft. The ship kept the samples in sealed containers and in November of the same year set off on a return voyage to Earth. In December 2020, as the ship flew by, it released test capsules that entered our atmosphere and were successfully detected in Australia. This week, we finally get to know what scientists have found from examining samples over the past year.
As a scientific warning Basic moments, two articles recently published on the subject indicate that Ryugu is dark and porous, and contains some of the oldest solar system materials scientists ever to get their hands on.
V first article notes that a C-type asteroid has an albedo (a measure of how much solar radiation it reflects) of 0.02. By comparison, most C-type asteroids fall in the 0.03 to 0.09 range. Asphalt is rated at 0.04. An albedo rating of 0.02 means that the asteroid reflects only two percent of all incoming solar radiation.
Ryugu also has a porosity of 46 percent, the conclusion says.
Scientists with second article presented their findings regarding the composition of the recovered material and found an extremely dark matrix, possibly dominated by phyllosilicates. Other minerals including carbonates, iron and volatiles have also been found in the matrix.
Further analysis will no doubt shed more light on the mysteries of Ryugu and perhaps help astronomers better understand the early days of our solar system.
Meanwhile, NASA is in the process of carrying out its own sample return mission. In October 2020, NASA’s OSIRIS-REx (Origin, Spectral Interpretation, Resource Identification, Safety, Regolith Explorer) spacecraft successfully took samples of the asteroid Bennu. The ship is expected to return a sample to Earth for analysis in late 2023.