The Japanese spacecraft Hayabusa 2 is approaching its target, the Ryugu asteroid

If all goes as planned, two spacecraft will start curious close encounters with two asteroids separated by the end of August. Their goal: to recover samples that may contain organic materials dating from the birth of the solar system. These building blocks may be the key to understanding the origins of planets and life on Earth – and could also enrich future space prospectors.

Japan's Hayabusa2 probe is about to arrive at a kilometer asteroid called Ryugu in June. 27. On August 17, a NASA engine, OSIRIS-REx, is expected to arrive in view of an asteroid about 500 meters wide called Bennu. These space rocks will be the subject of about two years of sensor surveys and efforts to collect samples for scientists on Earth for analysis.

"There are going to be so many groups in the world going to be able to study the samples for decades to come," says Nancy Chabot, a global scientist at Johns Hopkins University's Applied Physics Lab, who "The new data, she says," will really revolutionize what we understand about the composition and composition of these early primitive solar system bodies. "Hayabusa2 and OSIRIS-REx will not be the ones First missions to recover a sample of asteroids.This honor went to Japan's first spacecraft Hayabusa, which in 2010 returned to Earth with a small sample of the asteroid Itokawa after an unforeseen crash on its surface. Itokawa is representative of so-called S-type asteroids, consisting mainly of stony materials.

In contrast, Ryugu and Bennu belong to the class of carbon asteroids (type C), or carbonaceous, the most common, the space of rocks in the solar system. Taken together, the samples delivered by OSIRIS-REx and Hayabusa2 could confirm that these asteroids have a composition similar to that of the "carbonaceous chondrite" meteorites discovered on Earth. Such meteorites contain organic compounds in addition to water trapped in hydrated minerals. But these meteorites may have been contaminated by the surface of the Earth. If the composition of the asteroids corresponds to that of the meteorites, it would suggest that the compounds could have been brought here from space.

Carboniferous meteorites "very well may have been, at least in part, the source of water on Earth and the According to a joint statement by Harold Connolly, co-investigator and scientist of the mission sample for OSIRIS-REx, and Shogo Tachibana, a mission sample scientist for Hayabusa.2 This hypothesis could be reinforced by bringing back the first virgin samples of carbon asteroids.

The launch of two very similar missions may seem redundant, but it could be instructive, says Mr. Chabot. "If the samples [from both asteroids] prove to be identical, it would tell us something very fundamental about how homogeneous materials were in the solar system "But my money is on the samples showing surprising differences."

Both missions also have distinct operational phases. and collecting samples, Hayabusa2 will attempt to place up to three robot rovers and a MASCOT lander of European construction on Ryugu to explore its surface. The Japanese mission also plans to fire a two kilogram copper projectile at the asteroid; in this way, scientists hope to create a crater that reveals its internal composition.

The first Hayabusa mission brought back less than a milligram of asteroid dust from its historic and heartbreaking journey. The new missions could recover a larger area of ​​virgin rocks, facilitating the sharing and analysis of samples by researchers.

Hayabusa2 aims to collect three samples from different locations in Ryugu, taking about 100 milligrams. OSIRIS-REx will attempt to collect up to two kilograms from one place on Bennu's surface. Scientists from both missions plan to exchange samples and cooperate closely throughout: Connolly even works on both OSIRIS-REx and Hayabusa 2.

These missions can also provide valuable information for mining operations d & # 39; asteroids. She is a scientific advisor to Planetary Resources, an asteroid mining company based in Redmond, Washington. She is one of the companies hoping to harvest minerals from space and water rocks, which they could convert into rocket fuel.

Hayabusa2 and OSIRIS-REx are not expected to return to Earth until 2020 and 2023, respectively, but the reward will certainly be worth the wait. Dozens of years later, many laboratories are collecting new scientific data on Apollo's lunar samples, as improved techniques and instruments allow researchers to reanalyze old specimens.