It is a curious package that should land in the Woomera desert, in southern Australia, this Saturday, between 6 and 7 p.m. French time.
A “treasure box”, or “tamatebako” in Japanese, with dust from the asteroid Ryugu inside!
These should provide clues about the solar system when it was born 4.6 billion years ago, and the emergence of life on Earth.
Launched in December 2014, the Japanese probe Hayabusa 2 will therefore release this chamber into the atmosphere before leaving, if all goes without a hitch, towards another asteroid, 1998 KY26, for an arrival scheduled for 2031 ...
If this metal sled is ahead of Christmas, dropping the gift should be a formality, compared to the many times the actors on this mission have had to hold their breath in six years.
"For me, it was almost miraculous that everything worked", testifies astrophysicist Patrick Michel, member of the mission.
“When we arrived in Ryugu in June 2018, we really discovered something completely new.
These were the first detailed images of a carbonaceous asteroid that we discovered.
With, in addition, lots of assumptions we had made that turned out to be false, which was great for scientists like me because we had to rack our brains, but which complicated operations for the engineers ”, continues this research director at CNRS.
Hot shots
Among the surprises on arrival, an abundance of rocks.
Impossible to find a surface of more than 10 meters in which to land without risk, while the team had planned a margin of error of 50 m for the landing.
“We had to completely review the descent strategy on site in order to be able to increase the precision and go to less than 10 m”, explains Patrick Michel.
The first of the three descents intended for the collection of the samples was thus sacrificed to make an exercise.
The first harvest in February 2019 was not without a hitch either.
“I was in the operations room, I can tell you that we had one of these scares, remembers Patrick Michel.
At the start of the operation, which lasted 24 hours, we noticed that there was a bug in the navigation software: it gave a satellite position that was not correct.
We had to stop operations.
The Japanese went into the software, debugged it, sent it back, tested it.
It all took four hours.
And to make up for time, they descended at a much faster speed than initially expected.
"
Despite these heat waves, the Hayabusa 2 mission is a success, while the first of the name, completed in 2010, had encountered serial difficulties.
“When I was in Japan, we had Hayabusa's logbook.
In each place where there had been problems in the mission, we only ticked the good ones!
"
Jean-Pierre Bibring, French astrophysicist who will supervise the analysis of the samples, hails the “impressive efficiency” of the Japanese until the last step.
“The current trajectory has been defined with such precision that it makes it possible to aim at a point within a few kilometers in the Australian desert.
When you consider that all of this has been done for tens of millions of kilometers, it is truly remarkable.
"
View of the Woomera Desert, where the samples are to land.
AFP / Morgan Sette
More modest means than Osiris-Rex
It is difficult for Patrick Michel not to draw the parallel between Hayabusa 2 and the Osiris-Rex mission, from NASA, in which he is also collaborating and which must lead to the landing of a much larger sample of another asteroid, Bennu, in 2023.
Newsletter - Most of the news
Every morning, the news seen by Le Parisien
I'm registering
Your email address is collected by Le Parisien to enable you to receive our news and commercial offers.
Learn more
“With Osiris-Rex, we took two years, with a much larger team, to land and use a more complicated harvesting mechanism, allowing us to bring in a lot more.
While the Japanese did everything super fast: we arrived around Ryugu on June 27, 2018, without understanding what we were seeing, and in August, we already had to decide where we were going to harvest.
"
The surface of Ryugu.
ONC team
The information already gleaned allowed Patrick Michel to postulate that the two asteroids Ryugu and Bennu, with similar shapes close to that of a spinning top, would come from the destruction of the same celestial object.
But the carbonaceous compounds of Ryugu, the only ones for the moment in the process of being studied along with those of comet Tchouri, could also inform us about our origins and the foundations of the solar system.
Our idea of life challenged?
“We discovered that this material is mainly made from organic grains,” explains Jean-Pierre Bibring.
These grains presumably played a major role in what is called the emergence of life on Earth.
It is a similar material which was able, once sown in the primordial terrestrial oceans, to go towards the synthesis of living structures.
This is why we are very interested in all the missions that allow us to learn more about this material.
"
What if the living had not appeared suddenly but was rather the result of successive stages, dating back to the collapse of the cloud at the origin of the solar system?
Jean-Pierre Bibring considers it: “It is possible that the ideas which have been conveyed for centuries are called into question.
"
Patience!
Samples will start to be analyzed between late December and early January.
Jean-Pierre Bibring assures him: “As soon as there are important results, they will be immediately relayed to the general public.
»Developed under his leadership by the Institute of Space Astrophysics (IAS), the MicrOmega instrument will allow the composition of grains to be characterized by staying at a distance of a few centimeters, without touching them and therefore without altering them.
What is fortunate, in view of the supposedly very low volume, of the reported materials: 100 mg.
Patrick Michel is “betting that we will have a lot more”.
What if we believed in Santa Claus?