The Rosetta mission around the comet 67P/Tchourioumov-Guérassimenko is nearing its end. After almost two years of good and loyal services, the probe Station spatiale européenne (ESA) is going to crash Friday on “Tchouri”. Now too far from the Sun to operate the solar panels, it cannot in fact continue its work of analysis. But if the sending of the robot Philae has ended in failure, the data harvesting by Rosetta on the other hand has been very good. Europe 1 makes the balance on this exceptional mission, which revolutionized our knowledge of comets, but also on the emergence of life in the Universe.
sand and ice. the First major contribution of the Rosetta mission, launched in 2004, it has challenged what scientists had assumed about the comets. Suspected to just be balls of dirty ice, now, through the exploration of Tchouri, “one does not think any of it”, writes Alain Cirou, consultant area of Europe 1 and editor-in-chief of the magazine Sky and Space. The comet to be explored by the european probe is in fact rather “a pack of icy sand”. “This is very very original, is that it is a conglomerate of tiny grains, more black than coal, while being very lightweight because there is water ice trapped by these same grains,” explains the specialist.
Two key elements for life. As Tchouri has melted as it approached the Sun, Rosetta, thanks to its ten onboard instruments has been able to photograph and analyse the fruit of its oil spills. Gas and geysers have some surprises for scientists. Two of the molecules discovered are the same of the key elements for the emergence of life : glycine, an amino acid, and phosphorus, a key element of the DNA. For Alain Cirou, these findings are of the comet “a precious object”. But for what reason ? “We know that comets are born in the periphery of the cloud protosolaire (the origin of the formation of the solar system, ed)”, but the novelty provided by the Rosetta mission, is that “these comets are carriers of a hardware primitive”, a kind of “messengers of the cosmos bearers of a complex chemistry”, explains Alain Cirou.
The Rosetta probe will get closer little by little comet Tchouri these next six weeks. © ESA/ROSETTA/NAVCAM / AFP
The cosmos, unsuspected resources. what is it that these discoveries are changing for us, Earthlings ? Not much since the scenario of the origin of life on Earth is not modified : comets and asteroids have bombarded the Earth in its infancy, bringing all the ingredients for that living organisms developed in the oceans. “This is like a cooking recipe,” says Alain Cirou. “On the one hand, the flour, eggs, oil… this that brought the comets. And the cook, represented by the Earth, has led to the preparation of the cake : the life”. But the Rosetta mission has confirmed that, “the cosmos is manufactured naturally these ingredients there are more than 5 billion years” when comets have appeared. A revolution, considers the expert. Because if the cosmos knows how to make alone as a great of the useful material to life, it is enough to hope that life exists elsewhere, on another planet.
And then ? In addition to masses of data collected by Rosetta as it remains to analyze, the scientists expect much of the mission Osirix-Rex launched on September 9 by the Nasa. This sensor must reach by August 2018 the comet Bennu, which revolves around the sun in 1.2 years. After doing an analysis substantially similar to that of Rosetta with Tchouri, it will have to be closer to Bennu to collect samples. Planned return to Earth in 2023 with the precious cargo. “It’s a permanent quest”, underlines Alain Cirou. And also a way to catch what the robot Philae, dropped on Tchouri by Rosetta in November 2015, has not been able to do. Having landed in an area too little sun to operate the solar panels, it has not been able to dig as planned the sub-soil of the comet. Not really a failure in the light of the success of stunning the mission as a whole. Of what to encourage the ESA to replace the cover ? “She will decide that at the end of the year if it starts or not in a mission to an asteroid,” says the specialist.
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