Curiosity got the most important result of its missions.
A photo from open sources “Curiosity” on Mars NASA / JPL-Caltech
A team of scientists and engineers managing Curiosity said at a press conference in Washington that ancient Mars was fit for the existence of life. In fact, this means that rover descending to the surface of the Red Planet in August last year, has already fulfilled its mission.
It should be noted right away that Curiosity is not going to stop there. In April, he goes into forced “vacation” caused by the fact that Mars will be obscured by the Sun and the connection with Earth will become impossible. After that, in May, scientists gather repeat drilling of sedimentary rocks (the same “John Klein”, stone selected for its unusual light streaks) and again to analyze the obtained samples. Maybe Curiosity will even carry out several such drills, but sooner or later he will continue your journey to the foot of Mount Sharp, located in the center of Gale Crater. In the meantime, the second phase of the research mission not started, it makes sense to summarize some of the rover’s stay on the surface of the red planet and think what do they mean results.
Historical excursion
From the very beginning of the exploration of Mars, the interest of scientists was riveted to the possibility of life on it. This is understandable: Mars is more all other planets are similar to Earth, and in the past, before The red planet managed to cool down, the similarities were even more significant.
Search for traces of life was carried out with the help of the “Vikings” – the most the first vehicles to successfully descend to the surface of Mars. They are, like the Curiosity, they were equipped with similar devices: mass spectrometer and gas chromatograph. However, the names are not must be confusing, because modern appliances are similar to those which were used in the seventies of the last century, unless principle of work and name.
With all the success of the “Vikings,” the search with their help for life was still, in a sense, a false start. Mars surface turned out to be sterile, and analysis of organic compounds gave conflicting results. Researchers of the Red Planet decided take a step back and do not biology, but geology.
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Viking Lander on NASA Mars
The logic that guided the researchers is simple: life requires the existence of liquid water, and before looking for traces of life, traces of water must be found. It was these tasks that were set before the next generation of descent vehicles, the Sojerner, Spirit, Opportunity, and Phoenix. Huge role in the search Orbital probes – Odyssey and MRO – played the waters. All these studies have established that the planet has large water reserves, and was previously covered by vast seas and had full river system.
However, skeptics rightly claimed, in itself a great the amount of water does not mean that it could be suitable for of life. The possibility of its existence in water depends on the chemical composition of the latter. If water is, for example, saturated salt solution, then hope to detect any microorganisms in such a solution is not necessary. therefore research aimed at studying the composition of water once covering Mars, became one of the most important tasks Curiosity.
Nuclear fuel geologist
How can I establish the composition of the water that once covered Mars? Scientists use an elegant indirect method for this – study of sedimentary rocks. Although now the surface of the planet lifeless, covered with iron oxides and subject to space irradiation, inside the sedimentary rocks you can find a planet such which she was when these rocks were just forming.
All previous devices could not do this, because not were equipped with tools capable of penetrating below the surface stone. Closest to the study of the internal structure of Martian rocks came up “Spirit”, equipped with special brushes – RAT. “Curiosity” is the first device that has full drill and is able to penetrate into the rock to a depth of five centimeters.
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Travel Map of Curiosity Mars NASA / JPL-Caltech
It should be mentioned here that this depth is not impressive for everyone. scientists. Strong cosmic radiation penetrates Mars rocks and at a depth of up to ten centimeters capable of destroying almost any organics. If engineers could make a drill more truly, one could, with good reason, hope for discovery of interesting compounds.
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Curiosity Landing Ground was once an estuary марсианской реки. NASA / JPL-Caltech
The way in which Curiosity explores ancient water Mars is associated with the mechanism of sedimentary rock formation. therefore the place intended for the landing of the rover was chosen specifically for this task.
Gale Crater, where the Curiosity sank, is the accumulation of rocks that were deposited at the bottom of the recess many millions of years. It is believed that at least some of this deposition time was formed from the water filling the crater. how this went on for a long time – a moot point, but in the end the water in the crater has disappeared, and in its center due to strong weathering Mount Sharpe formed. It actually is puff cake from sedimentary rocks and therefore contains information about millions years of Mars history. The foot of the mountain should be the end point Travel “Curiosity”.
The landing site of the device in Gale Crater was also not chosen. by chance, but determined during a long debate. It is not just a convenient platform, but of scientific interest: in a place where the rover descended on Mars, previously there was a river estuary, descending from the elevation of the crater. Like on Earth, the river should have been bring along silt and a suspension that can tell a lot about the nature of the river and the composition of the water. Even if during descent from something happened and he wouldn’t be able to go to Mount Sharp, Curiosity could have been quite productive time where it originally appeared. Fortunately, the landing was over successfully and did not have to resort to a backup scenario – the rover hit the road.
Martian Chronicles
The first goal of his journey was the crater area, which received name Glenelg. As shown by images using the orbital MRO apparatus, three geological types of the Martian intersect here the soil. The area is located just 400 meters from the landing site, but at the way to it, Curiosity made periodic stops and had already managed get some interesting results.
The first significant discovery was made after two months on Mars. September 27, it became known that the device found the bed of a dried-out stream. Of course, the water channels were found on Mars long before that, however, it was the Curiosity managed to be the first to find real pebbles – it almost never differed from earthly. Scientists were even able to estimate the speed of water in such a creek – they said, it was about one meter in give me a sec. The discovery once again confirmed the correct choice of place landing, but, of course, said nothing about the chemical composition Martian water.
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The bed of a dried-up stream on Mars (left) and on Earth (right) NASA / JPL-Caltech
In early October, the Curiosity team announced a study caught on the way to Glenelg stone “Jake Matievich.” This a small cobblestone became the first object that the rover simultaneously studied with two devices – ChemCam and APXS. First, most futuristic from an impressive set of tools vaporize a piece of rock with a laser beam and determine it chemical composition of the resulting glow. APXS allows more examine in detail the structure of a mineral by irradiating it alpha particles and watching their reflection.
“Jake” turned out to be an interesting object – it consisted mainly from feldspar and had a reduced content magnesium and iron – properties that were not previously found Spirit, nor Opportunity. However, Jake’s research they didn’t give anything to study water, because this stone had volcanic origin.
The next important step in the work of Curiosity was the study dusty Martian soil in X-ray diffraction CheMin spectrometer. This device gives much more information about minerals, as it explores not only their chemical composition, but also crystalline structure.
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“Джейк Матиевич” с точками облучения лазером.NASA/JPL-Caltech
The analysis showed that the soil is approximately half composed of amorphous volcanic sand, and the other half of the volume is weathering products of crystallized volcanic rocks – feldspar, pyroxene and olivine. In your message researchers compared such a soil to terrestrial volcanic rocks that are found in Hawaii. Not to say that these the results were unexpected, rather the opposite. More importantly, the rover in fact tested one of its most powerful instruments, intended, by and large, primarily for analysis drilling products.
While at the end of 2012, the rover was approaching Glenelg, on Earth There was a strange story related to his data. First mission supervisor John Grotzinger in a radio interview told about some data that “will go into history textbooks”, and then the head of the Jet Propulsion Laboratory (JPL, units NASA), bypassing official channels, told reporters that “Curiosity” (in his opinion, Grotzinger, discovered) on Mars organic matter. In the end, the story ended up being reliable it was possible to prove only the presence of perchlorate – a simple compound chlorine and oxygen. The same carbon compounds that were initially found to be the reaction products of perchlorate with carbon from the Earth.
Drilling
Finally, in mid-January 2013, six months after the beginning of work, Curiosity chose a target for the first drilling. Her turned out to be a stone called by researchers “John Klein” by named after one of the mission leaders who died in 2011. Even by the first photographs of the stone made it clear that the target was chosen unusual. “John Klein” contained a large number of white veins which, according to geologists, almost certainly constitute calcium sulfate, or, more simply, gypsum. The exact same veins found in terrestrial minerals – they form when water moves in the cracks.
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Ten Years of Progress: Researching the Spirit Stones (Left) and “Кьюриосити” (справа) NASA/JPL-Caltech
February 4, the rover drilled the surface of the John Klein and received samples from the depths of the stone. Rock powder obtained during drilling, went to the CheMin spectrometer and the largest instrument Mars rover – gas analyzer SAM (Sample Analisys at Mars). The test results became known only a month later.
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Clay minerals are formed in the channels of Pershoy rivers NASA/JPL-Caltech
Scientists found that approximately 20 percent of the investigated the stone consists of fine sedimentary rocks, the rest is part is occupied by volcanic minerals. This finely divided part is actually compacted clay that is almost no different from the one that can be found on Earth in beds of dried rivers. It is formed as a result of gradual sedimentation of suspended matter from water.
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Delivery of drilling products to the internal devices of the rover NASA/JPL-Caltech
The composition of the studied rocks indicated that the water from which they besieged, was quite ordinary, neutral and relatively unsalted. Perhaps she could even be drunk. But the most interesting was that sulfur was present in sedimentary rocks different chemical forms that could serve as an energy source for bacteria. Such microorganisms are well known on Earth – they they transfer one substance to another and extract energy from it. Studies have shown that they could exist on Mars.
Not so fast
It should be emphasized that the discovery of conditions suitable for life certainly does not mean the very existence of life (although lightness meteorite travel from planet to planet makes you think about this theme). Similarly, the presence of microorganisms is nothing says the existence of an energy source for them – still Curiosity has not received any clear evidence in the benefit of their existence. However, so far received the results look very encouraging and in this case sound how solid can be.
Alexander Ershov
Water Time Life Stones Mars Mars Rover Curiosity
